arXiv daily: Astrophysics of Galaxies

arXiv daily: Astrophysics of Galaxies (astro-ph.GA)

1.The growth history of local M33-mass bulgeless spiral galaxies

Authors:Xiaoyu Kang, Rolf-Peter Kudritzki, Fenghui Zhang

Abstract: NGC\,7793, NGC\,300, M33 and NGC\,2403 are four nearby undisturbed and bulgeless low-mass spiral galaxies with similar morphology and stellar mass. They are ideal laboratories to study disc formation scenarios and stellar mass growth histories. We construct a simple chemical evolution model by assuming that discs grow gradually with continuous metal-free gas infall and metal-enriched gas outflow. By means of the classical $\chi^{2}$ methodology, applied to the model predictions, the best combination of free parameters capable of reproducing the corresponding present-day observations is determined, i.e. the radial dependence of the infall timescale $\tau=0.1r/{R_{\rm d}}+3.4\,{\rm Gyr}$ ($R_{\rm d}$ is the disc scale-length) and the gas outflow efficiency $b_{\rm out}=0.2$. The model results are in excellent agreement with the general predictions of the inside-out growth scenario for the evolution of spiral galaxies. About 80\% of the stellar mass of NGC\,7793 is assembled within the last 8\,Gyr and 40\% within the last 4\,Gyr. By comparing the best-fitting model results of the three other galaxies we obtain similar results, 72\% (NGC\,300), 66\% (NGC\,2403) and 79\% (M33) stellar mass were assembled within the past $\sim\rm 8\,Gyr$ (i.e. $z\,=\,1$). These four disc galaxies simultaneously increase their sizes and stellar masses as time goes by and they grow in size at $\sim\,0.30$ times the rate at which they grow in mass. The scale-lengths of these four discs are now 20\% -- 25\% larger than at $z\,=\,1$. Our best-fitting model predicted the stellar mass-metallicity relation and the metallicity gradients, constrained by the observed metallicities from HII-regions emission line analysis, agree well with the observations measured from individual massive red and blue supergiant stars and population synthesis of SDSS galaxies.

2.Preprocessing in small groups: Three simulated galaxies interacting prior to cluster infall

Authors:Ewa L. Lokas

Abstract: The formation of galaxy clusters is a complicated process that probably involves the accretion of galaxies in groups, as observed in nearby clusters, such as Virgo and Fornax. The members of the groups undergo "preprocessing" prior to cluster infall, which affects their stellar populations and morphology. In this paper I present an extreme example of such an accretion event selected from the IllustrisTNG100 simulation. The group, composed of three full-sized disky galaxies and a number of smaller satellites, is accreted early, with the first pericenter around the cluster at redshift z=1.3. Before the infall, the three galaxies interact strongly in pairs within the group, which produces tidally induced bars in the two more massive ones. The interactions also lead to mass exchange and trigger some star formation activity resulting in temporary rejuvenation of their stellar populations. After infall, they all undergo seven pericenter passages around the cluster, experiencing strong mass loss in the dark matter and gas components, as well as reddening of the stellar populations. Their tidally induced bars are, however, preserved and even enhanced probably due to the loss of gas via ram-pressure stripping in the intracluster medium. The study demonstrates that group accretion can happen very early in cluster formation and proposes another scenario for the formation of tidally induced bars.

3.Kinetic Study of the Gas-Phase Reaction between Atomic Carbon and Acetone. Low Temperature Rate Constants and Hydrogen Atom Product Yields

Authors:Kevin M. Hickson, Jean-Christophe Loison, Valentine Wakelam

Abstract: The reactions of ground state atomic carbon, C(3P), are likely to be important in astrochemistry due to the high abundance levels of these atoms in the dense interstellar medium. Here we present a study of the gas-phase reaction between C(3P) and acetone, CH3COCH3. Experimentally, rate constants were measured for this process over the 50 to 296 K range using a continuous-flow supersonic reactor, while secondary measurements of H(2S) atom formation were also performed over the 75 to 296 K range to elucidate the preferred product channels. C(3P) atoms were generated by In-situ pulsed photolysis of carbon tetrabromide, while both C(3P) and H(2S) atoms were detected by pulsed laser induced fluorescence. Theoretically, quantum chemical calculations were performed to obtain the various complexes, adducts and transition states involved in the C(3P) + CH3COCH3 reaction over the 3A'' potential energy surface, allowing us to better understand the reaction pathways and help to interpret the experimental results. The derived rate constants are large, (2-3) x 10-10 cm3 s-1 , displaying only weak temperature variations; a result that is consistent with the barrierless nature of the reaction. As this reaction is not present in current astrochemical networks, its influence on simulated interstellar acetone abundances is tested using a gas-grain dense interstellar cloud model. For interstellar modelling purposes, the use of a temperature independent value for the rate constant, k(C+CH3COCH3 )= 2.2 x 10-10 cm3 s-1, is recommended. The C(3P) + CH3COCH3 reaction decreases gas-phase CH3COCH3 abundances by as much as two orders of magnitude at early and intermediate cloud ages.

4.The dusty heart of Circinus II. Scrutinizing the LM-band dust morphology using MATISSE

Authors:Jacob W. Isbell, Jörg-Uwe Pott, Klaus Meisenheimer, Marko Stalevski, Konrad R. W. Tristram, James Leftley, Daniel Asmus, Gerd Weigelt, Violeta Gámez Rosas, Romain Petrov, Walter Jaffe, Karl-Heinz Hofmann, Thomas Henning, Bruno Lopez

Abstract: In this paper we present the first-ever $L$- and $M$-band interferometric observations of Circinus, building upon a recent $N$-band analysis. We used these observations to reconstruct images and fit Gaussian models to the $L$ and $M$ bands. Our findings reveal a thin edge-on disk whose width is marginally resolved and is the spectral continuation of the disk imaged in the $N$ band to shorter wavelengths. Additionally, we find a point-like source in the $L$ and $M$ bands that, based on the $LMN$-band spectral energy distribution fit, corresponds to the $N$-band point source. We also demonstrate that there is no trace of direct sightlines to hot dust surfaces in the circumnuclear dust structure of Circinus. By assuming the dust is present, we find that obscuration of A$_{\rm V} \gtrsim 250$ mag is necessary to reproduce the measured fluxes. Hence, the imaged disk could play the role of the obscuring "torus" in the unified scheme of active galactic nuclei. Furthermore, we explored the parameter space of the disk + hyperbolic cone radiative transfer models and identify a simple modification at the base of the cone. Adding a cluster of clumps just above the disk and inside the base of the hyperbolic cone provides a much better match to the observed temperature distribution in the central aperture. This aligns well with the radiation-driven fountain models that have recently emerged. Only the unique combination of sensitivity and spatial resolution of the VLTI allows such models to be scrutinized and constrained in detail. We plan to test the applicability of this detailed dust structure to other MATISSE-observed active galactic nuclei in the future.

5.Discerning Parallax Amplitude in Astrometric Microlensing

Authors:Sedighe Sajadian, Arya Mahmoudzadeh, Setareh Moein

Abstract: Gravitational microlensing is a powerful method for discovering Isolated Stellar-Mass Black Holes(ISMBHs). These objects make long-duration microlensing events. To characterize these lensing objects by fully resolving the microlensing degeneracy, measurements of parallax and astrometric deflections are necessary. Microlensing events due to ISMBHs have considerable astrometric deflections, but small parallax amplitudes as $\pi_{\rm E} \propto 1/\sqrt{M_{\rm l}}$, where $M_{\rm l}$ is the lens mass. We numerically investigate the possibility of inferring parallax amplitude from astrometric deflection in microlensing events due to ISMBHs. The parallax amplitude in astrometric deflections is proportional to the relative parallax $\pi_{\rm{rel}}$, which means (i) does not strongly depend on $M_{\rm l}$, and (ii) increases in microlensing observations toward the Magellanic Clouds(MCs). We assume these events are potentially detected in upcoming microlensing surveys-(1): the \wfirst\ observations of the Galactic bulge (GB), and (2): the LSST observations of the Large MC(LMC)-, and the Extremely Large Telescope (ELT) follows up them with one data point every ten days. We evaluate the probability of inferring parallax amplitude from these observations by calculating the Fisher/Covariance matrices. For GB, the efficiencies for discerning parallax amplitudes with a relative error $<4\%$ through astrometric, and photometric observations are $3.8\%$, and $29.1\%$, respectively. For observations toward the LMC, these efficiencies are $41.1\%$, and $23.0\%$, respectively. Measuring parallax amplitude through astrometric deflections is plausible in the GB events with the lens distance $\lesssim 2.7$kpc, and in the LMC halo-lensing. The ELT telescope by monitoring long-duration microlensing events can detect astrometric deflections, and their parallax-induced deviations.

6.DUALZ -- Deep UNCOVER-ALMA Legacy High-$Z$ Survey

Authors:Seiji Fujimoto, Rachel Bezanson, Ivo Labbe, Gabriel Brammer, Sedona H. Price, Bingjie Wang, John R. Weaver, Yoshinobu Fudamoto, Pascal A. Oesch, Christina C. Williams, Pratika Dayal, Robert Feldmann, Jenny E. Greene, Joel Leja, Katherine E. Whitaker, Adi Zitrin, Sam E. Cutler, Lukas J. Furtak, Richard Pan, Iryna Chemerynska, Vasily Kokorev, Tim B. Miller, Hakim Atek, Pieter van Dokkum, Stephanie Juneau, Susan Kassin, Gourav Khullar, Danilo Marchesini, Michael Maseda, Erica J. Nelson, David J. Setton, Renske Smit

Abstract: We present the survey design and initial results of the ALMA Cycle~9 program of DUALZ, which aims to establish a joint ALMA and JWST public legacy field targeting the massive galaxy cluster Abell 2744. DUALZ features a contiguous $4'\times6'$ ALMA 30-GHz-wide mosaic in Band 6, covering areas of $\mu>2$ down to a sensitivity of $\sigma=32.7$~$\mu$Jy. Through a blind search, we identified 69 dust continuum sources at S/N $\gtrsim5.0$ with median redshift and intrinsic 1.2-mm flux of $z=2.30$ and $S_{\rm 1.2mm}^{\rm int}=0.24$~mJy. Of these, 27 have been spectroscopically confirmed, leveraged by the latest NIRSpec observations, while photometric redshift estimates are constrained by the comprehensive \hst, NIRCam, and ALMA data for the remaining sources. With priors, we further identify a \cii158~$\mu$m line emitter at $z=6.3254\pm0.0004$, confirmed by the latest NIRSpec spectroscopy. The NIRCam counterparts of the 1.2-mm continuum exhibit undisturbed morphologies, denoted either by disk or spheroid, implying the triggers for the faint mm emission are less catastrophic than mergers. We have identified 8 \hst-dark galaxies (F150W$>$27~mag, F150W$-$F444W$>$2.3) and 2 JWST-dark (F444W$>$30~mag) galaxy candidates among the ALMA continuum sources. The former includes face-on disk galaxies, hinting that substantial dust obscuration does not always result from inclination. We also detect a marginal dust emission from an X-ray-detected galaxy at $z_{\rm spec}=10.07$, suggesting an active co-evolution of the central black hole and its host. We assess the infrared luminosity function up to $z\sim10$ and find it consistent with predictions from galaxy formation models. To foster diverse scientific outcomes from the community, we publicly release reduced ALMA mosaic maps, cubes, and the source catalog (URL:\#DUALZ).

7.An Observationally Driven Multifield Approach for Probing the Circum-Galactic Medium with Convolutional Neural Networks

Authors:Naomi Gluck Yale University, Benjamin D. Oppenheimer University of Colorado Boulder, Daisuke Nagai Yale University, Francisco Villaescusa-Navarro Princeton University Center for Computational Astrophysics, Flatiron Institute, Daniel Angéles-Alcázar University of Connecticut Center for Computational Astrophysics, Flatiron Institute

Abstract: The circum-galactic medium (CGM) can feasibly be mapped by multiwavelength surveys covering broad swaths of the sky. With multiple large datasets becoming available in the near future, we develop a likelihood-free Deep Learning technique using convolutional neural networks (CNNs) to infer broad-scale physical properties of a galaxy's CGM and its halo mass for the first time. Using CAMELS (Cosmology and Astrophysics with MachinE Learning Simulations) data, including IllustrisTNG, SIMBA, and Astrid models, we train CNNs on Soft X-ray and 21-cm (HI) radio 2D maps to trace hot and cool gas, respectively, around galaxies, groups, and clusters. Our CNNs offer the unique ability to train and test on ''multifield'' datasets comprised of both HI and X-ray maps, providing complementary information about physical CGM properties and improved inferences. Applying eRASS:4 survey limits shows that X-ray is not powerful enough to infer individual halos with masses $\log(M_{\rm{halo}}/M_{\odot}) < 12.5$. The multifield improves the inference for all halo masses. Generally, the CNN trained and tested on Astrid (SIMBA) can most (least) accurately infer CGM properties. Cross-simulation analysis -- training on one galaxy formation model and testing on another -- highlights the challenges of developing CNNs trained on a single model to marginalize over astrophysical uncertainties and perform robust inferences on real data. The next crucial step in improving the resulting inferences on physical CGM properties hinges on our ability to interpret these deep-learning models.

8.Expanding on the Fundamental Metallicity Relation in Dwarf Galaxies with MUSE

Authors:Teodora-Elena Bulichi, Katja Fahrion, François Mernier, Michael Hilker, Ryan Leaman, Mariya Lyubenova, Oliver Müller, Nadine Neumayer, Ignacio Martin Navarro, Francesca Pinna, Marina Rejkuba, Laura Scholz-Diaz, Glenn van de Ven

Abstract: The mass-metallicity relation (MZR) represents one of the most important scaling relations in the context of galaxy evolution, comprising a positive correlation between stellar mass and metallicity (Z). The fundamental metallicity relation (FMR) introduces a new parameter, the star formation rate (SFR), in the dependence. While several studies found that Z is anti-correlated with the SFR at fixed mass, the validity of this statement has been questioned extensively and no widely-accepted consensus has been reached yet. With this work, we investigate the FMR in nine nearby, spatially-resolved, dwarf galaxies, using gas diagnostics on integral-field spectroscopic data of the Multi Unit Spectroscopic Explorer (MUSE), pushing such investigations to lower galaxy masses and higher resolutions. We find that both the MZR and FMR exhibit different behaviours within different star forming regions of the galaxies. We find that the SFR surface density - metallicity anti-correlation is tighter in the low-mass galaxies of our sample. For all the galaxies considered, we find a SFR surface density - stellar mass surface density correlation. We propose that the main reason behind these findings is connected to the accretion mechanisms of the gas fuelling star formation -- low-mass, metal-poor galaxies accrete pristine gas from the intergalactic medium, while in more massive and metal-enriched systems the gas responsible for star formation is recycled from previous star forming episodes.

1.Unravelling the Nuclear Dust Morphology of NGC 1365: A Two Phase Polar - RAT Model for the Ultraviolet to Infrared Spectral Energy Distribution

Authors:Subhashree Swain, P. Shalima, K. V. P. Latha

Abstract: We present a 3D radiative transfer model for the Spectral Energy Distribution (SED) of NGC 1365, which is a "changing look" Seyfert 1.8 type AGN. The SED from the ultraviolet (UV) to the infrared (IR) is constructed using archival data from the UVIT on-board $AstroSat$, along with IR data from the literature. The SKIRT radiative transfer code is used to model the SED and derive the geometry and composition of dust in this AGN. Similar to our earlier SED model of NGC 4151, the nuclear region of NGC 1365 is assumed to contain a ring or disk-like structure concentric to the accretion disk, composed of large (0.1$\mu$m - 1$\mu$m) graphite grains in addition to the two-phase dusty torus made up of ISM-type grains (Ring And Torus or RAT model). We also include, for the first time, an additional component of dusty wind in the form of a bipolar cone. We carry out a detailed analysis and derive the best-fit parameters from a $\chi^2 $ test to be $R_{\rm in,r}$ = 0.03 pc, $\sigma$ = 26$^\circ$ and $\tau$ = 20 for the assumed ring-torus-polar wind geometry. Our results suggest the presence of hot dust at a temperature T $\sim$ 1216 K at the location of the ring which absorbs and scatters the incident UV radiation and emits in the near-IR (NIR). In the mid-IR (MIR) the major contributors are the polar cone and warm dust with T $\sim$ 916 K at $R_{\rm in,t}$ = 0.1 pc. Not only are our model radii in agreement with IR interferometric observations, our study also reiterates the role of high resolution UV observations in constraining the dust grain size distribution in the nuclear regions of AGN.

2.Understanding Molecular Abundances in Star-Forming Regions Using Interpretable Machine Learning

Authors:Johannes Heyl, Joshua Butterworth, Serena Viti

Abstract: Astrochemical modelling of the interstellar medium typically makes use of complex computational codes with parameters whose values can be varied. It is not always clear what the exact nature of the relationship is between these input parameters and the output molecular abundances. In this work, a feature importance analysis is conducted using SHapley Additive exPlanations (SHAP), an interpretable machine learning technique, to identify the most important physical parameters as well as their relationship with each output. The outputs are the abundances of species and ratios of abundances. In order to reduce the time taken for this process, a neural network emulator is trained to model each species' output abundance and this emulator is used to perform the interpretable machine learning. SHAP is then used to further explore the relationship between the physical features and the abundances for the various species and ratios we considered. \ce{H2O} and CO's gas phase abundances are found to strongly depend on the metallicity. \ce{NH3} has a strong temperature dependence, with there being two temperature regimes (< 100 K and > 100K). By analysing the chemical network, we relate this to the chemical reactions in our network and find the increased temperature results in increased efficiency of destruction pathways. We investigate the HCN/HNC ratio and show that it can be used as a cosmic thermometer, agreeing with the literature. This ratio is also found to be correlated with the metallicity. The HCN/CS ratio serves as a density tracer, but also has three separate temperature-dependence regimes, which are linked to the chemistry of the two molecules.

3.Discovery of a molecular cloud possibly associated with the youngest Galactic SNR G1.9+0.3

Authors:Rei Enokiya, Hidetoshi Sano, Miroslav D. Filipovic, Rami Z. E. Alsaberi, Tsuyoshi Inoue And Tomoharu Oka

Abstract: The youngest known Galactic supernova remnant (SNR) G1.9+0.3 has high-velocity supernova shock beyond 10000 km s-1, and it is considered to be one of the major candidates of a PeVatron. Despite these outstanding properties, the surrounding interstellar matter of this object is poorly understood. We investigated the interstellar gas toward G1.9+0.3 using the 12CO(J=3-2) data with the angular resolution of 15" obtained by the CHIMPS2 survey by the James Clerk Maxwell Telescope, and discovered three individual clouds at -1, 7, and 45 km s-1. From its morphological and velocity structures, the -1 km s-1 cloud, having the largest velocity width >20 km s-1 and located at the distance of the Galactic Center, is possibly associated with the SNR. The associated cloud shows a cavity structure both in space and velocity and coincides well with the SNR. We found that the associated cloud has higher column densities toward three bright, radio synchrotron-emitted rims where the radial expansion velocity of the supernova shock is decelerated, and the cloud is faint in the other parts of the SNR. This is the first direct evidence indicating that the highly anisotropic expansion of G1.9+0.3 observed by previous studies results from the deceleration by the interaction between the supernova shock and surrounding dense interstellar medium.

4.Science opportunities for IMAP-Lo observations of ISN He, Ne and O

Authors:M. A. Kubiak, M. Bzowski, P. Swaczyna, E. Moebius, N. A. Schwadron, D. J. McComas

Abstract: Direct-sampling observations of interstellar neutral (ISN) species and their secondary populations inform on the physical state of the local interstellar medium and processes operating in the outer heliosheath. Such observations are performed from Earth's orbit by the IBEX-Lo experiment on board the Interstellar Boundary Explorer (IBEX) mission. IBEX ISN viewing is restricted to directions close to perpendicular to the Earth-Sun line, which limits the observations of interstellar species to several months during the year. A greatly improved data set will be possible for the upcoming IMAP mission due to a novel concept of putting the IMAP-Lo detector on a pivot platform that varies the angle of observation relative to the Sun-Earth line and the detector boresight, as planned for the IMAP-Lo instrument on the Interstellar Mapping and Acceleration Probe (IMAP) mission (McComas et al. 2018). Here we suggest a 2 year scenario for varying the viewing angle in such a way that all the necessary atom components can be observed sufficiently well to achieve the science goals of nominal IMAP mission. This scenario facilitates, among others, removal of the correlation of the inflow parameters of interstellar gas, unambiguous analysis of the primary and secondary populations of interstellar He, Ne and O, and determination of the ionization rates of He and Ne free of possible calibration bias. The scheme is operationally simple, provides a good counting statistics, and synergizes observations of interstellar species and heliospheric energetic neutral atoms.

5.EPOCHS VIII. An Insight into MIRI-selected Galaxies in SMACS-0723 and the Benefits of Deep MIRI Photometry in Revealing AGN and the Dusty Universe

Authors:Qiong Li, Christopher J. Conselice, Nathan Adams, James A. A. Trussler, Duncan Austin, Tom Harvey, Leonardo Ferreira, Joseph Caruana, Katherine Ormerod, Ignas Juodžbalis

Abstract: We present the analysis of the stellar population and star formation history of 181 MIRI selected galaxies at redshift 0-3.5 in the massive galaxy cluster field SMACS J0723.3-7327, commonly referred to as SMACS0723, using the James Webb Space Telescope (JWST) Mid-Infrared Instrument (MIRI). We combine the data with the JWST Near Infrared Camera (NIRCam) catalogue, in conjunction with the Hubble Space Telescope (HST) WFC3/IR and ACS imaging. We find that the MIRI bands capture PAH features and dust emission, significantly enhancing the accuracy of photometric redshift and measurements of the physical properties of these galaxies. The median photo-z's of galaxies with MIRI data are found to have a small 0.1% difference from spectroscopic redshifts and reducing the error by 20 percent. With MIRI data included in SED fits, we find that the measured stellar masses are unchanged, while the star formation rate is systematically lower by 0.1 dex. We also fit the median SED of active galactic nuclei (AGN) and star forming galaxies (SFG) separately. MIRI data provides tighter constraints on the AGN contribution, reducing the typical AGN contributions by ~14 percent. In addition, we also compare the median SED obtained with and without MIRI, and we find that including MIRI data yields steeper optical and UV slopes, indicating bluer colours, lower dust attenuation, and younger stellar populations. In the future, MIRI/MRS will enhance our understanding by providing more detailed spectral information and allowing for the study of specific emission features and diagnostics associated with AGN.

6.When and how does ram pressure stripping in low-mass satellite galaxies enhance star formation

Authors:Jingyao Zhu, Stephanie Tonnesen, Greg L Bryan

Abstract: We investigate how a satellite's star formation rate (SFR) and surviving gas respond to ram pressure stripping in various environments. Using a suite of high-resolution "wind-tunnel" simulations with radiative cooling, star formation, and supernovae feedback, we model the first infall orbit of a low-mass disk galaxy ($M_{*} = 10^{9.7} M_{\odot}$) in different host halos, ranging from Milky Way-like to cluster hosts. When the ram pressure is moderate, we find that the stripping satellite shows an enhanced SFR relative to the isolated control case, despite gas loss due to stripping. The SFR enhancement is caused, not directly by compression, but by ram pressure-driven mass flows, which can increase the dense gas fraction in the central disk regions. The spatially-resolved star formation main sequence and Kennicutt-Schmidt relations in our simulations are consistent with recent findings of the VERTICO and GASP surveys. Our results predict the environmental signals of RPS in future multiwavelength, high-angular resolution observations: the star formation and gas surface densities will be centralized, and symmetrically enhanced within the stripping radius.

1.Neutral Hydrogen content of dwarf galaxies in different environments

Authors:Hui-Jie Hu, Qi Guo, Pablo Renard, Hang Yang, Zheng Zheng, Yingjie Jing, Hao Chen, Hui Li

Abstract: Environments play an important role in galaxy formation and evolution, particularly in regulating the content of neutral gas. However, current HI surveys have limitations in their depth, which prevents them from adequately studying low HI content galaxies in high-density regions. In this study, we address this issue by employing the Five-hundred-meter Aperture Spherical radio Telescope (FAST) with extensive integration times to complement the relatively shallow Arecibo Legacy Fast Arecibo L-band Feed Array (ALFALFA) HI survey. This approach allows us to explore the gas content of dwarf galaxies across various environments. We observe a positive relationship between HI mass and stellar mass in dwarf galaxies, with a well-defined upper boundary for HI mass that holds true in both observations and simulations. Furthermore, we find a decrease in the HI-to-stellar mass ratio ($\rm M_{\rm HI}/M_*$) as the density of the environment increases, irrespective of whether it is determined by the proximity to the nearest group or the projected number density. Comparing our observations to simulations, we note a steeper slope in the relationship, indicating a gradual gas-stripping process in the observational data. Additionally, we find that the scaling relation between the $\rm M_{\rm HI}/M_*$ and optical properties can be improved by incorporating galaxy environments.

2.Gaia's brightest very metal-poor (VMP) stars: A metallicity catalogue of a thousand VMP stars from Gaia RVS spectra

Authors:Akshara Viswanathan, Else Starkenburg, Tadafumi Matsuno, Kim A. Venn, Nicolas F. Martin, Nicolas Longeard, Anke Ardern-Arentsen, Raymond G. Carlberg, Sebastien Fabbro, Georges Kordopatis, Martin Montelius, Federico Sestito, Zhen Yuan

Abstract: Context. Gaia DR3 has offered the scientific community a remarkable dataset of approximately one million spectra acquired with the Radial Velocity Spectrometer (RVS) in the Calcium II triplet region, that is well-suited to identify very metal-poor (VMP) stars. However, over 40% of these spectra have no released parameters by Gaia's GSP Spec pipeline in the domain of VMP stars, whereas VMP stars are key tracers of early Galactic evolution. Aims. We aim to provide spectroscopic metallicities for VMP stars using Gaia RVS spectra, thereby producing a catalogue of bright VMP stars distributed over the full sky that can serve as the basis to study early chemical evolution throughout the Galaxy. Methods. We select VMP stars using photometric metallicities from the literature and analyse the Gaia RVS spectra to infer spectroscopic metallicities for these stars. Results. The inferred metallicities agree very well with literature high-resolution metallicities with a median systematic offset of 0.1 dex and standard deviation of $\sim$0.15 dex. The purity of this sample in the VMP regime is $\sim$80% with outliers representing a mere $\sim$3%. Conclusions. We make available an all-sky catalogue of $\sim$1500 stars with reliable spectroscopic metallicities down to [Fe/H]$\sim$-4.0, of which $\sim$1000 are VMP stars. More than 75% of these stars have either no metallicity value in the literature to date or are flagged to be unreliable in their literature metallicity estimates. This catalogue of bright (G<13) VMP stars is three times larger than the current sample of well-studied VMP stars in the literature in this magnitude range, making it ideal for high-resolution spectroscopic follow-up and to study the properties of VMP stars in different parts of our Galaxy.

3.The Three Hundred: $M_{sub}-V_{circ}$ relation

Authors:Atulit Srivastava, Weiguang Cui, Massimo Meneghetti, Romeel Dave, Alexander Knebe, Antonio Ragagnin, Carlo Giocoli, Francesco Calura, Giulia Despali, Lauro Moscardini, Gustavo Yepes

Abstract: In this study, we investigate a recent finding based on strong lensing observations, which suggests that the sub-halos observed in clusters exhibit greater compactness compared to those predicted by $\Lambda$CDM simulations. To address this discrepancy, we performed a comparative analysis by comparing the cumulative mass function of sub-halos and the $M_{\text{sub}}$-$V_{\text{circ}}$ relation between observed clusters and 324 simulated clusters from The Three Hundred project, focusing on re-simulations using GADGET-X and GIZMO-SIMBA baryonic models. The sub-halos' cumulative mass function of the GIZMO-SIMBA simulated clusters agrees with observations, while the GADGET-X simulations exhibit discrepancies in the lower sub-halo mass range possibly due to its strong SuperNova feedback. Both GADGET-X and GIZMO-SIMBA simulations demonstrate a redshift evolution of the sub-halo mass function and the $V_{max}$ function, with slightly fewer sub-halos observed at lower redshifts. Neither the GADGET-X nor GIZMO-SIMBA(albeit a little closer) simulated clusters' predictions for the $M_{\text{sub}}$-$V_{\text{circ}}$ relation align with the observational result. Further investigations on the correlation between sub-halo/halo properties and the discrepancy in the $M_{\text{sub}}$-$V_{\text{circ}}$ relation reveals that the sub-halo's half mass radius and galaxy stellar age, the baryon fraction and sub-halo distance from the cluster's centre, as well as the halo relaxation state play important roles on this relation. Nevertheless, we think it is still challenging in accurately reproducing the observed $M_{\text{sub}}$-$V_{\text{circ}}$ relation in our current hydrodynamic cluster simulation under the standard $\Lambda$CDM cosmology.

4.The problem of dust attenuation in photometric decomposition of edge-on galaxies and possible solutions

Authors:Sergey Savchenko, Denis Poliakov, Aleksandr Mosenkov, Anton Smirnov, Alexander Marchuk, Vladimir Il'in, George Gontcharov, Jonah Seguine, Maarten Baes

Abstract: The presence of dust in spiral galaxies affects the ability of photometric decompositions to retrieve the parameters of their main structural components. For galaxies in an edge-on orientation, the optical depth integrated over the line-of-sight is significantly higher than for those with intermediate or face-on inclinations, so it is only natural to expect that for edge-on galaxies, dust attenuation should severely influence measured structural parameters. In this paper, we use radiative transfer simulations to generate a set of synthetic images of edge-on galaxies which are then analysed via decomposition. Our results demonstrate that for edge-on galaxies, the observed systematic errors of the fit parameters are significantly higher than for moderately inclined galaxies. Even for models with a relatively low dust content, all structural parameters suffer offsets that are far from negligible. In our search for ways to reduce the impact of dust on retrieved structural parameters, we test several approaches, including various masking methods and an analytical model that incorporates dust absorption. We show that using such techniques greatly improves the reliability of decompositions for edge-on galaxies.

5.Co-moving groups around massive stars in the Nuclear Stellar Disk

Authors:Á. Martínez-Arranz, R. Schödel, F. Nogueras-Lara, M. Hosek, F. Najarro

Abstract: During the last $\sim$ 30 Myr the nuclear stellar disk in the Galactic center has been the most prolific star forming region of the Milky Way when averaged by volume. Remarkably, the combined mass of the only three clusters present today in the nuclear stellar disk adds up to only $\sim$10\% of the total expected mass of young stars formed in this period. Several causes could explain this apparent absence of clusters and stellar associations. The stellar density in the area is so high that only the most massive clusters would be detectable against the dense background of stars. The extreme tidal forces reigning in the Galactic center could dissolve even the most massive of the clusters in just a few Myr. Close encounters with one of the massive molecular clouds, that are abundant in the nuclear stellar disk, can also rapidly make any massive cluster or stellar association dissolve beyond recognition. However, traces of some dissolving young clusters/associations could still be detectable as co-moving groups. It is our aim to identify so far unknown clusters or groups of young stars in the Galactic Center. We focus our search on known, spectroscopically identified massive young stars to see whether they can pinpoint such structures. We created an algorithm to detect over-densities in the five-dimensional space spanned by proper-motion, position on the plane of the sky and line-of-sight distances, using reddening as a proxy for the latter. Since co-moving groups must be young in this environment, proper motions provide a good means to search for young stars in the Galactic center. We found four co-moving groups around massive stars, two of which are very close in position and velocity to the Arches' most likely orbit

6.Spatially-resolved Spectroscopic Analysis of Ly$α$ Haloes: Radial Evolution of the Ly$α$ Line Profile out to 60 kpc

Authors:Yucheng Guo, Roland Bacon, Lutz Wisotzki, Thibault Garel, Jérémy Blaizot, Joop Schaye, Jorryt Matthee, Floriane Leclercq, Leindert Boogaard, Johan Richard, Anne Verhamme, Jarle Brinchmann, Léo Michel-Dansac, Haruka Kusakabe

Abstract: Deep MUSE observations have unveiled pervasive Ly$\alpha$ haloes (LAHs) surrounding high-redshift star-forming galaxies. However, the origin of the extended Ly$\alpha$ emission is still a subject of debate. We analyse the average spatial extent and spectral variation of the circumgalactic LAHs by stacking a sample of 155 Ly$\alpha$ emitters (LAEs) at redshift $3<z<4$ in the MUSE Extremely Deep Field (MXDF). With respect to the Ly$\alpha$ red peak of the target LAE, the Ly$\alpha$ line peak becomes increasingly more blueshifted out to a projected distance of at least 60 kpc, where the velocity offset is $\approx$ 250 km/s. This signal is observed in both the mean and median stacks, and is thus a generic property of the LAE sample with typical Ly$\alpha$ luminosity $\mathrm{\approx 10^{41.1} erg\,s^{-1}}$. We discuss multiple scenarios to explain the blueshift of the circumgalactic Ly$\alpha$ line. The most plausible one is a combination of outflows and inflows. In the inner region of the LAH, the Ly$\alpha$ photons are produced by the central star formation and then scattered within outflows. At larger radii, the infalling cool gas shapes the observed Ly$\alpha$ blueshift.

7.Spatially-resolved H$α$ and ionizing photon production efficiency in the lensed galaxy MACS1149-JD1 at a redshift of 9.11

Authors:J. Álvarez-Márquez, L. Colina, A. Crespo Gómez, P. Rinaldi, J. Melinder, G. Östlin, M. Annunziatella, A. Labiano, A. Bik, S. Bosman, T. R. Greve, G. Wright, A. Alonso-Herrero, L. Boogaard, R. Azollini, K. I. Caputi, L. Costantin, A. Eckart, M. GarcÍa-MarÍn, S. Gillman, J. Hjorth, E. Iani, O. Ilbert, I. Jermann, D. Langeroodi, R. Meyer, F. Peissker, P. Pérez-González, J. P. Pye, T. Tikkanen, M. Topinka, P. van der Werf, F. Walter, Th. Henning, T. Ray

Abstract: We present MIRI/JWST medium resolution spectroscopy (MRS) and imaging (MIRIM) of the lensed galaxy MACS1149-JD1 at a redshift of $z$=9.1092$\pm$0.0002 (Universe age about 530 Myr). We detect, for the first time, spatially-resolved H$\alpha$ emission in a galaxy at redshift above 9. The structure of the H$\alpha$ emitting gas consists of two clumps, S and N. The total H$\alpha$ luminosity implies an instantaneous star formation rate of 5.3$\pm$0.4 $M_{\odot}$ yr$^{-1}$ for solar metallicities. The ionizing photon production efficiency, $\log(\zeta_\mathrm{ion})$, shows a spatially-resolved structure with values of 25.55$\pm$0.03, 25.47$\pm$0.03, and 25.91$\pm$0.09 Hz erg$^{-1}$ for the integrated galaxy, and clumps S and N, respectively. The H$\alpha$ rest-frame equivalent width, EW$_{0}$(H$\alpha$), is 491$^{+334}_{-128}$ \'Angstrom for the integrated galaxy, but presents extreme values of 363$^{+187}_{-87}$ \'Angstrom and $\geq$1543 \'Angstrom for clumps S and N, respectively. The spatially-resolved ionizing photon production efficiency is within the range of values measured in galaxies at redshift above six, and well above the canonical value (25.2$\pm$0.1 Hz erg$^{-1}$). The extreme difference of EW$_{0}$(H$\alpha$) for Clumps S and N indicates the presence of a recent (few Myr old) burst in clump N and a star formation over a larger period of time (e.g. 100$-$200 Myr) in clump S. Finally, clump S and N show very different H$\alpha$ kinematics with velocity dispersions of 56$\pm$4 km s$^{-1}$ and 113$\pm$33 km s$^{-1}$, likely indicating the presence of outflows or increased turbulence in the clump N. The dynamical mass, $M_\mathrm{dyn}$= (2.4$\pm$0.5)$\times$10$^{9}$ $M_{\odot}$, is within the range previously measured with the spatially-resolved [OIII]88$\mu$m line.

8.Into the Mystic: ALMA ACA observations of the Mystic Mountains in Carina

Authors:Megan Reiter, P. D. Klaassen, L. Moser-Fischer, A. F. McLeod, D. Itrich

Abstract: We present new observations of the Mystic Mountains cloud complex in the Carina Nebula using the ALMA Atacama Compact Array (ACA) to quantify the impact of strong UV radiation on the structure and kinematics of the gas. Our Band~6 observations target CO, $^{13}$CO, and C$^{18}$O; we also detect DCN J=3-2 and $^{13}$CS J=5-4. A dendrogram analysis reveals that the Mystic Mountains are a coherent structure, with continuous emission over $-$10.5 km s$^{-1}$ $<$ v < $-$2 km s$^{-1}$. We perform multiple analyses to isolate non-thermal motions in the Mystic Mountains including computing the turbulent driving parameter, $b$, which indicates whether compressive or solenoidal modes dominate. Each analysis yields values similar to other pillars in Carina that have been observed in a similar way but are subject to an order of magnitude less intense ionizing radiation. We find no clear correlation between the velocity or turbulent structure of the gas and the incident radiation, in contrast to other studies targeting different regions of Carina. This may reflect differences in the initial densities of regions that go on to collapse into pillars and those that still look like clouds or walls in the present day. Pre-existing over-densities that enable pillar formation may also explain why star formation in the pillars appears more evolved (from the presence of jets) than in other heavily-irradiated but non-pillar-like regions. High resolution observations of regions subject to an array of incident radiation are required to test this hypothesis.

1.A severe challenge to the MOND phenomenology in our Galaxy

Authors:Man Ho Chan, Ka Chung Law

Abstract: Modified Newtonian Dynamics (MOND) is one of the most popular alternative theories of dark matter to explain the missing mass problem in galaxies. Although it remains controversial regarding MOND as a fundamental theory, MOND phenomenology has been shown to widely apply in different galaxies, which gives challenges to the standard $\Lambda$ cold dark matter model. In this article, we derive analytically the galactic rotation curve gradient in the MOND framework and present a rigorous analysis to examine the MOND phenomenology in our Galaxy. By assuming a benchmark baryonic disk density profile and two popular families of MOND interpolating functions, we show for the first time that the recent discovery of the declining Galactic rotation curve in the outer region ($R \approx 17-23$ kpc) can almost rule out the MOND phenomenology at more than $5\sigma$. This strongly supports some of the previous studies claiming that MOND is neither a fundamental theory nor a universal description of galactic properties.

2.Ionized regions in the central arcsecond of NGC 1068. YJHK spatially resolved spectroscopy

Authors:P. Vermot, B. Barna, S. Ehlerová, M. R. Morris, J. Palous, R. Wünsch

Abstract: Context. Several bright emission line regions have been observed in the central 100 parsecs of the active galaxy NGC 1068. Aims. We aim to determine the properties and ionization mechanism of three regions of NGC 1068: the nucleus (B) and two clouds located at 0.3" and 0.7" north of it (C and D). Methods. We combined SPHERE (0.95 - 1.65 um) and SINFONI (1.5 - 2.45 um) spectra for the three regions B, C, and D. We compared these spectra to several CLOUDY photoionization models and to the MAPPINGS III Library of Fast Radiative Shock Models. Results. The emission line spectra of the three regions are almost identical to each other and contribute to most of the emission line flux in the nuclear region. The emitting media contain multiple phases, the most luminous of which have temperatures ranging from 104.8 K to 106 K. Central photoionization models can reproduce some features of the spectra, but the fast radiative shock model provides the best fit to the data. Conclusions. The similarity between the three regions indicates that they belong to the same class of objects. Based on our comparisons, we conclude that they are shock regions located where the jet of the active galactic nucleus impacts massive molecular clouds.

3.FOREVER22: Gas and metal outflow from massive galaxies in protocluster regions

Authors:Naoki Harada, Hidenobu Yajima, Makito Abe

Abstract: We study gas and metal outflow from massive galaxies in protocluster regions at $z=3-9$ by using the results of the FOREVER22 simulation project. Our simulations contain massive haloes with $M_{\rm h} \gtrsim 10^{13}~\rm M_{\odot}$, showing high star formation rates of $> 100~\rm M_{\odot}~yr^{-1}$ and hosting supermassive black holes with $M_{\rm BH} \gtrsim 10^{8}~\rm M_{\odot}$. We show that the mass loading factor ($\eta_{\rm M}$) sensitively depends on the halo mass and it is $\eta_{\rm M} = 1.2~(9.2)$ for $M_{\rm h} = 10^{13}~(10^{11})~\rm M_{\odot}$. Once the halo mass exceeds $\sim 10^{12.5}~\rm M_{\odot}$, the outflow velocity of the gas rapidly decreases near a virial radius, and the gas returns to a galactic centre finally as a fountain flow. Also, the metal inflow and outflow rates sensitively depend on the halo mass and redshift. At $z=3$, the inflow rate becomes larger than the outflow one if $M_{\rm h} \gtrsim 10^{13.0}~\rm M_{\odot}$. Thus, we suggest that massive haloes cannot be efficient metal enrichment sources beyond virial radii that will be probed in future observations, e.g., studies of metal absorption lines with the Prime Focus Spectrograph on the Subaru telescope.

4.Gas-phase metallicity of local AGN in the GASP and MaNGA surveys: the role of ram-pressure stripping

Authors:Giorgia Peluso, Mario Radovich, Alessia Moretti, Matilde Mingozzi, Benedetta Vulcani, Bianca Poggianti, Antonino Marasco, Marco Gullieuszik

Abstract: Growing evidence in support of a connection between Active Galactic Nuclei (AGN) activity and the Ram-Pressure Stripping (RPS) phenomenon has been found both observationally and theoretically in the past decades. In this work, we further explore the impact of RPS on the AGN activity by estimating the gas-phase metallicity of nuclear regions and the mass-metallicity relation of galaxies at $z \leq$ 0.07 and with stellar masses $\log {\rm M}_* / {\rm M}_\odot \geq 9.0 $, either experiencing RPS or not. To measure oxygen abundances, we exploit Integral Field Spectroscopy data from the GASP and MaNGA surveys, photoionization models generated with the code CLOUDY and the code Nebulabayes to compare models and observations. In particular, we build CLOUDY models to reproduce line ratios induced by photoionization from stars, AGN, or a contribution of both. We find that the distributions of metallicity and [O III]$\lambda$5007 luminosity of galaxies undergoing RPS are similar to the ones of undisturbed galaxies. Independently of the RPS, we do not find a correlation between stellar mass and AGN metallicity in the mass range $\log {\rm M}_* / {\rm M}_\odot \geq 10.4$, while for the star-forming galaxies we observe the well-known mass-metallicity relation (MZR) between $ 9.0 \leq \log \ {\rm M}_* /{\rm M}_\odot \leq 10.8$ with a scatter mainly driven by the star-formation rate (SFR) and a plateau around $\log {\rm M}_* / {\rm M}_\odot \sim 10.5$. The gas-phase metallicity in the nuclei of AGN hosts is enhanced with respect to those of SF galaxies by a factor of $\sim$ 0.05 dex regardless of the RPS.

5.An in-depth view of the metallicity distribution of the Small Magellanic Cloud

Authors:Andrés E. Piatti

Abstract: The spatial metallicity distribution of star clusters in the Small Magellanic Cloud (SMC) has recently been found to correlate as a V-shaped function with the semi-major axis of an elliptical framework proposed to assume a projected galaxy flattening. We report results on the impact that the use of such a framework can produce on our understanding of the SMC formation and its chemical enrichment. We show that clusters with similar semi-major axes are placed at a very different distances from the SMC centre. The recently claimed bimodal metallicity distribution of clusters projected on the innermost SMC regions and the V-shaped metallicity gradient fade away when actual distances are used. Although a large dispersion prevails, clusters older than $\sim$ 1 Gyr exhibit a shallow metallicity gradient, caused by slightly different spatial distributions of clusters younger and older than $\sim$ 4 Gyr; the former being more centrally concentrated and having a mean metallicity ([Fe/H]) $\sim$ 0.15 dex more metal-rich than that of older clusters. This metallicity gradient does not show any dependence with the position angle, except for clusters placed beyond 11 kpc, which are located in the eastern side of the galaxy.

6.Median Surface Brightness Profiles of Lyman-$α$ Haloes in the MUSE Extremely Deep Field

Authors:Yucheng Guo, Roland Bacon, Lutz Wisotzki, Thibault Garel, Jérémy Blaizot, Joop Schaye, Johan Richard, Yohana Herrero Alonso, Floriane Leclercq, Leindert Boogaard, Haruka Kusakabe, John Pharo

Abstract: We present the median surface brightness profiles of diffuse Ly$\alpha$ haloes (LAHs) around star-forming galaxies by stacking 155 spectroscopically confirmed Ly$\alpha$ emitters (LAEs) at 3<z<4 in the MUSE Extremely Deep Field (MXDF), with median Ly$\alpha$ luminosity $\mathrm{L_{Ly\alpha} \approx 10^{41.1} erg\,s^{-1}}$. After correcting for a systematic surface brightness offset we identified in the datacube, we detect extended Ly$\alpha$ emission out to a distance of 270 kpc. The median Ly$\alpha$ surface brightness profile shows a power-law decrease in the inner 20 kpc, and a possible flattening trend at larger distance. This shape is similar for LAEs with different Ly$\alpha$ luminosities, but the normalisation of the surface brightness profile increases with luminosity. At distances larger than 50 kpc, we observe strong overlap of adjacent LAHs, and the Ly$\alpha$ surface brightness is dominated by the LAHs of nearby LAEs. We find no clear evidence of redshift evolution of the observed Ly$\alpha$ profiles when comparing with samples at 4<z<5 and 5<z<6. Our results are consistent with a scenario in which the inner 20 kpc of the LAH is powered by star formation in the central galaxy, while the LAH beyond a radius of 50 kpc is dominated by photons from surrounding galaxies.

7.Kinematics and Collimation of the Two-Sided Jets in NGC 4261: VLBI Study on Sub-parsec Scales

Authors:Xi Yan, Ru-Sen Lu, Wu Jiang, Thomas P. Krichbaum, Zhi-Qiang Shen

Abstract: We report multi-frequency VLBI studies of the sub-parsec scale structure of the two-sided jet in the nearby radio galaxy NGC 4261. Our analyses include new observations using the Source Frequency Phase Referencing technique with the Very Long Baseline Array at 44 and 88 GHz, as well as archival data at 15 and 43 GHz. Our results show an extended double-sided structure at 43/44 GHz and provide a clear image of the nuclear region at 88 GHz, showing a core size of $\sim$0.09 mas and a brightness temperature of $\sim1.3\times10^{9}$ K. Proper motions are measured for the first time in the two-sided jet, with apparent speeds ranging from $0.31\pm0.14\,c$ to $0.59\pm0.40\,c$ in the approaching jet and $0.32\pm0.14\,c$ in the receding jet. The jet-to-counter-jet brightness ratio allows us to constrain the viewing angle to between $\sim54^{\circ}$ and $84^{\circ}$ and the intrinsic speed to between $\sim0.30\,c$ and $0.55\,c$. We confirm the parabolic shape of the upstream jet on both sides of the central engine, with a power-law index of $0.56\pm0.07$. Notably, the jet collimation is found to be already completed at sub-parsec scales, with a transition location of about 0.61 pc, which is significantly smaller than the Bondi radius of 99.2 pc. This behavior can be interpreted as the initial confinement of the jet by external pressure from either the geometrically thick, optically thin advection-dominated accretion flows (ADAF) or the disk wind launched from it. Alternatively, the shape transition may also be explained by the internal flow transition from a magnetically dominated to a particle-dominated regime.

8.Can massive stars form in low mass clouds?

Authors:Jamie D. Smith, Sarah E. Jaffa, Martin G. H. Krause

Abstract: The conditions required for massive star formation are debated, particularly whether massive stars must form in conjunction with massive clusters. Some authors have advanced the view that stars of any mass (below the total cluster mass) can form in clusters of any mass with some probability (random sampling). Others pointed out that the scatter in the determinations of the most massive star mass for a given cluster mass was consistent with the measurement error, such that the mass of the most massive star was determined by the total cluster mass (optimal sampling). Here we investigate the relation between cluster mass (M\textsubscript{ecl}) and the maximum stellar mass (M\textsubscript{max}) using a suite of SPH simulations. Varying cloud mass and turbulence random seed results in a range of cluster masses which we compare with their respective maximum star masses. We find that more massive clusters will have, on average, higher mass stars with this trend being steeper at lower cluster masses ($M\textsubscript{max} \propto M\textsubscript{ecl}^{0.31}$ for $M\textsubscript{ecl}<500M\,_{\odot}$) and flattening at higher cluster masses ($M\textsubscript{max} \propto M\textsubscript{ecl}^{0.11}$ for $M\textsubscript{ecl}>500M\,_{\odot}$). This rules out purely stochastic star formation in our simulations. Significant scatter in the maximum masses with identical initial conditions also rules out the possibility that the relation is purely deterministic (that is that a given cluster mass will result in a specific maximum stellar mass). In conclusion our simulations disagree with both random and optimal sampling of the initial mass function.

1.A multiphase study of classical Cepheids in the Magellanic Clouds- Models and Observations

Authors:Kerdaris Kurbah, Shashi M. Kanbur, Sukanta Deb, Susmita Das, Mami Deka, Anupam Bhardwaj, Hugh Riley Randal, Selim Kalici

Abstract: This work presents the study of multiphase relations of classical Cepheids in the Magellanic Clouds for short periods (log P < 1) and long periods (log P > 1). From the analysis, it has been found that the multiphase relations obtained using the models as well as observations are highly dynamic with pulsational phase. The multiphase relations for short and long periods are found to display contrasting behaviour for both LMC and SMC. It has been observed that the multiphase relations obtained using the models agree better with the observations in the PC plane in most phases in comparison to the PL plane. Multiphase relations obtained using the models display a clear distinction among different convection sets in most phases. Comparison of models and observations in the multiphase plane is one way to test the models with the observations and to constrain the theory of stellar pulsation.

2.Magnetic Fields and Velocity Gradients in L1551: The Role of Stellar Feedback

Authors:Mingrui Liu, Yue Hu, Alex Lazarian

Abstract: Magnetic fields play a crucial role in star formation, yet tracing them becomes particularly challenging, especially in the presence of outflow feedback in protostellar systems. We targeted the star-forming region L1551, notable for its apparent outflows, to investigate the magnetic fields. These fields were probed using polarimetry observations from the Planck satellite at 353 GHZ/849 $\mu$m, the SOFIA/HAWC+ measurement at 214 $\mu$m, and the JCMT SCUPOL 850 $\mu$m survey. Consistently, all three measurements show that the magnetic fields twist towards the protostar IRS 5. Furthermore, we used the Velocity Gradients Technique (VGT) and the $^{12}$CO (J = 1-0) emission data to distinguish the magnetic fields directly associated with the protostellar outflows. These were then compared with the polarization results. Notably, in the outskirts of the region, these measurements generally align. However, as one approaches the center of IRS 5, the measurements tend to yield mostly perpendicular relative orientations. This suggests that the outflows might be dynamically significant from a scale of approximately $\sim0.2$ pc, causing the velocity gradient to change direction by 90 degrees. Furthermore, we discovered that the polarization fraction $p$ and the total intensity $I$ correlate as $p \propto I^{-\alpha}$. Specifically, $\alpha$ is approximately $1.044\pm0.06$ for SCUPOL and around $0.858\pm0.15$ for HAWC+. This indicates that the outflows could significantly impact the alignment of dust grains and magnetic fields in the L1551 region.

3.Astrometric VLBI observations of H$_2$O masers in an extreme OH/IR star candidate NSV17351

Authors:Akiharu Nakagawa, Atsushi Morita, Nobuyuki Sakai, Tomoharu Kurayama, Hiroshi Sudou, Gabor Orosz, Akito Yuda, Daichi Kaseda, Masako Matsuno, Shota Hamada, Toshihiro Omodaka, Yuji Ueno, Katsunori M. Shibata, Yoshiaki Tamura, Takaaki Jike, Ken Hirano, Mareki Honma

Abstract: Results of astrometric very long baseline interferometry (VLBI) observations towards an extreme OH/IR star candidate NSV17351 are presented. We used the VERA (VLBI Exploration of Radio Astrometry) VLBI array to observe 22\,GHz H$_2$O masers of NSV17351. We derived an annual parallax of 0.247$\pm$0.035 mas which corresponds to a distance of 4.05$\pm$0.59 kpc. By averaging the proper motions of 15 maser spots, we obtained the systemic proper motion of NSV17351 to be ($\mu_{\alpha}\cos{\delta}, \mu_{\delta}$)$^{\mathrm{avg}}$ $=$ ($-$1.19 $\pm$ 0.11, 1.30 $\pm$ 0.19) mas\,yr$^{-1}$. The maser spots spread out over a region of 20 mas $\times$ 30 mas, which can be converted to a spatial distribution of $\sim$80 au $\times$ $\sim$120 au at the source distance. Internal motions of the maser spots suggest an outward moving maser region with respect to the estimated position of the central star. From single dish monitoring of the H$_2$O maser emission, we estimate the pulsation period of NSV17351 to be 1122$\pm$24 days. This is the first report of the periodic activity of NSV17351, indicating that NSV17351 could have a mass of $\sim$4\,M$_{\odot}$. We confirmed that the time variation of H$_2$O masers can be used as a period estimator of variable OH/IR stars. Furthermore, by inspecting dozens of double-peaked H$_2$O maser spectra from the last 40 years, we detected a long-term acceleration in the radial velocity of the circumstellar matter to be $0.17\pm0.03$ km\,s$^{-1}$\,yr$^{-1}$ Finally, we determined the position and kinematics of NSV17351 in the Milky Way Galaxy and found that NSV17351 is located in an interarm region between the Outer and Perseus arms. We note that astrometric VLBI observations towards extreme OH/IR stars are useful samples for studies of the Galactic dynamics.

4.Investigating a Global Collapsing Hub-Filament Cloud G326.611+0.811

Authors:Yu-Xin He, Hong-Li Liu, Xin-Di Tang, Sheng-Li Qin, Jian-Jun Zhou, Jarken Esimbek, Si-Rong Pan, Da-Lei Li, Meng-Ke Zhao, Wei-Guang Ji, Toktarkhan Komesh

Abstract: We present the dynamics study toward the G326.611+0.811 (G326) hub-filament-system (HFS) cloud using the new APEX observations of both $^{13}$CO and C$^{18}$O (J = 2-1). The G326 HFS cloud constitutes a central hub and at least four hub-composing filaments that are divided into a major branch of filaments (F1, and F2) and a side branch (F3-F5). The cloud holds ongoing high-mass star formation as characterised by three massive dense clumps (i.e., 370-1100 $M_{\odot}$ and 0.14-0.16 g cm$^{-2}$ for C1-C3) with the high clump-averaged mass infalling rates ($>10^{-3}$ $M_{\odot}$ yr$^{-1}$) within in the major filament branch, and the associated point sources bright at 70 $\mu$m typical of young protostars. Along the five filaments, the velocity gradients are found in both $^{13}$CO and C$^{18}$O (J = 2-1) emission, suggesting that the filament-aligned gravitational collapse toward the central hub (i.e., C2) is being at work for high-mass star formation therein. Moreover, a periodic velocity oscillation along the major filament branch is revealed in both $^{13}$CO and C$^{18}$O (J = 2-1) emission with a characteristic wavelength of $\sim$3.5 pc and an amplitude of $\sim$0.31-0.38 km s$^{-1}$. We suggest that this pattern of velocity oscillation in G326 could arise from the clump-forming gas motions induced by gravitational instability. Taking into account the prevalent velocity gradients, the fragmentation of the major branch of filaments, and the ongoing collapse of the three massive dense clumps, it is indicative that G326 is a HFS undergoing global collapse.

5.High-resolution APEX/LAsMA $^{12}$CO and $^{13}$CO (3-2) observation of the G333 giant molecular cloud complex : II. Survival and gravitational collapse of dense gas structures under feedback

Authors:J. W. Zhou, F. Wyrowski, S. Neupane, I. Barlach Christensen, K. M. Menten, S. H. Li, T. Liu

Abstract: We investigate the physical properties of gas structures under feedback in the G333 complex using data of the 13CO (3-2) line in the LAsMA observation. We used the Dendrogram algorithm to identify molecular gas structures based on the integrated intensity map of the 13CO (3-2) emission, and extracted the average spectra of all structures to investigate their velocity components and gas kinematics. We derive the column density ratios between different transitions of the 13CO emission pixel-by-pixel, and find the peak values N(2-1)/N(1-0) ~ 0.5, N(3-2)/N(1-0) ~ 0.3, N(3-2)/N(2-1) ~ 0.5. These ratios can also be roughly predicted by RADEX for an average H$_2$ volume density of ~ 4.2 * 10$^3$ cm$^{-3}$. A classical virial analysis does not reflect the true physical state of the identified structures, and we find that external pressure from the ambient cloud plays an important role in confining the observed gas structures. For high column density structures, velocity dispersion and density show a clear correlation, while for low column density structures they do not, indicating the contribution of gravitational collapse to the velocity dispersion. For both leaf and branch structures, $\sigma-N*R$ always has a stronger correlation compared to $\sigma-N$ and $\sigma-R$. The scaling relations are stronger, and have steeper slopes when considering only self-gravitating structures, which are the structures most closely associated with the Heyer-relation. Although the feedback disrupting the molecular clouds will break up the original cloud complex, the substructures of the original complex can be reorganized into new gravitationally governed configurations around new gravitational centers. This process is accompanied by structural destruction and generation, and changes in gravitational centers, but gravitational collapse is always ongoing.

6.Andromeda's Parachute: Time Delays and Hubble Constant

Authors:Vyacheslav N. Shalyapin, Luis J. Goicoechea, Karianne Dyrland, Håkon Dahle

Abstract: The gravitational lens system PS J0147+4630 (Andromeda's Parachute) consists of four quasar images ABCD and a lensing galaxy. We obtained $r$-band light curves of ABCD in the 2017$-$2022 period from monitoring with two 2-m class telescopes. Applying state-of-the-art curve shifting algorithms to these light curves led to measurements of time delays between images, and the three independent delays relative to image D are accurate enough to be used in cosmological studies (uncertainty of about 4%): $\Delta t_{\rm{AD}}$ = $-$170.5 $\pm$ 7.0, $\Delta t_{\rm{BD}}$ = $-$170.4 $\pm$ 6.0, and $\Delta t_{\rm{CD}}$ = $-$177.0 $\pm$ 6.5 d, where image D is trailing all the other images. Our finely sampled light curves and some additional fluxes in the years 2010$-$2013 also demonstrated the presence of significant microlensing variations. From the measured delays relative to image D and typical values of the external convergence, recent lens mass models yielded a Hubble constant that is in clear disagreement with currently accepted values around 70 km s$^{-1}$ Mpc$^{-1}$. We discuss how to account for a standard value of the Hubble constant without invoking the presence of an extraordinary high external convergence.

7.EPOCHS VI: The Size and Shape Evolution of Galaxies since z ~ 8 with JWST Observations

Authors:K. Ormerod, C. J. Conselice, N. J. Adams, T. Harvey, D. Austin, J. Trussler, L. Ferreira, J. Caruana, G. Lucatelli, Q. Li, W. J. Roper

Abstract: We present the results of a size and structural analysis of 1395 galaxies at $0.5 \leq z \lesssim 8$ with stellar masses $\log \left(M_* / M_{\odot}\right)$ $>$ 9.5 within the JWST Public CEERS field that overlaps with the HST CANDELS EGS observations. We use GALFIT to fit single S\'ersic models to the rest-frame optical profile of our galaxies, which is a mass-selected sample complete to our redshift and mass limit. Our primary result is that at fixed rest-frame wavelength and stellar mass, galaxies get progressively smaller, evolving as $\sim (1+z)^{-0.71\pm0.19}$ up to $z \sim 8$. We discover that the vast majority of massive galaxies at high redshifts have low S\'ersic indices, thus do not contain steep, concentrated light profiles. Additionally, we explore the evolution of the size-stellar mass relationship, finding a correlation such that more massive systems are larger up to $z \sim 3$. This relationship breaks down at $z > 3$, where we find that galaxies are of similar sizes, regardless of their star formation rates and S\'ersic index, varying little with mass. We show that galaxies are more compact at redder wavelengths, independent of sSFR or stellar mass up to $z \sim 3$. We demonstrate the size evolution of galaxies continues up to $z \sim 8$, showing that the process or causes for this evolution is active at early times. We discuss these results in terms of ideas behind galaxy formation and evolution at early epochs, such as their importance in tracing processes driving size evolution, including minor mergers and AGN activity.

8.The impermanent fate of massive stars in AGN disks

Authors:Mohamad Ali-Dib, Douglas N. C. Lin

Abstract: Stars are likely to form or to be captured in AGN disks. Their mass reaches an equilibrium when their rate of accretion is balanced by that of wind. If the exchanged gas is well mixed with the stellar core, this metabolic process would indefinitely sustain an "immortal" state on the main sequence (MS) and pollute the disk with He byproducts. This theoretical extrapolation is inconsistent with the super-solar {\alpha} element and Fe abundances inferred from the broad emission lines in active AGNs with modest He concentration. We show this paradox can be resolved with a highly-efficient retention of the He ashes or the suppression of chemical blending. The latter mechanism is robust in the geometrically-thin, dense, sub-pc regions of the disk where the embedded-stars' mass is limited by the gap-formation condition. These stars contain a radiative zone between their mass-exchange stellar surface and the nuclear-burning core. Insulation of the core lead to the gradual decrease of its H fuel and the stars' equilibrium masses. These stars transition to their post-main-sequence (PostMS) tracks on a chemical evolution time scale of a few Myr. Subsequently, the triple-{\alpha} and {\alpha}-chain reactions generate {\alpha} and Fe byproducts which are released into their natal disks. These PostMS stars also undergo core collapse, set off type II supernova, and leave behind a few solar-mass residual black holes or neutron stars

9.A search for faint resolved galaxies beyond the Milky Way in DES Year 6: A new faint, diffuse dwarf satellite of NGC 55

Authors:M. McNanna, K. Bechtol, S. Mau, E. O. Nadler, J. Medoff, A. Drlica-Wagner, W. Cerny, D. Crnojevic, B. Mutlu-Pakdil, A. K. Vivas, A. B. Pace, J. L. Carlin, M. L. M. Collins, D. Martinez-Delgado, C. E. Martinez-Vazquez, N. E. D. Noel, A. H. Riley, D. J. Sand, A. Smercina, R. H. Wechsler, T. M. C. Abbott, M. Aguena, O. Alves, D. Bacon, C. R. Bom, D. Brooks, D. L. Burke, J. A. Carballo-Bello, A. Carnero Rosell, J. Carretero, L. N. da Costa, T. M. Davis, J. De Vicente, H. T. Diehl, P. Doel, I. Ferrero, J. Frieman, G. Giannini, D. Gruen, G. Gutierrez, R. A. Gruendl, S. R. Hinton, D. L. Hollowood, K. Honscheid, D. J. James, K. Kuehn, J. L. Marshall, J. Mena-Fernandez, R. Miquel, M. E. S. Pereira, A. Pieres, A. A. Plazas Malagon, J. D. Sakowska, E. Sanchez, D. Sanchez Cid, B. Santiago, I. Sevilla-Noarbe, M. Smith, G. S. Stringfellow, E. Suchyta, M. E. C. Swanson, G. Tarle, N. Weaverdyck, P. Wiseman

Abstract: We report results from a systematic wide-area search for faint dwarf galaxies at heliocentric distances from 0.3 to 2 Mpc using the full six years of data from the Dark Energy Survey (DES). Unlike previous searches over the DES data, this search specifically targeted a field population of faint galaxies located beyond the Milky Way virial radius. We derive our detection efficiency for faint, resolved dwarf galaxies in the Local Volume with a set of synthetic galaxies and expect our search to be complete to $M_V$ ~ $(-7, -10)$ mag for galaxies at $D = (0.3, 2.0)$ Mpc respectively. We find no new field dwarfs in the DES footprint, but we report the discovery of one high-significance candidate dwarf galaxy at a distance of $2.2\substack{+0.05\\-0.12}$ Mpc, a potential satellite of the Local Volume galaxy NGC 55, separated by $47$ arcmin (physical separation as small as 30 kpc). We estimate this dwarf galaxy to have an absolute V-band magnitude of $-8.0\substack{+0.5\\-0.3}$ mag and an azimuthally averaged physical half-light radius of $2.2\substack{+0.5\\-0.4}$ kpc, making this one of the lowest surface brightness galaxies ever found with $\mu = 32.3$ mag ${\rm arcsec}^{-2}$. This is the largest, most diffuse galaxy known at this luminosity, suggesting possible tidal interactions with its host.

1.On the encounter between the GASP galaxy JO36 and the radio plume of GIN 049

Authors:Alessandro Ignesti, Marisa Brienza, Benedetta Vulcani, Bianca M. Poggianti, Antonino Marasco, Rory Smith, Martin Hardcastle, Andrea Botteon, Ian D. Roberts, Jacopo Fritz, Rosita Paladino, Myriam Gitti, Anna Wolter, Neven Tomčić, Sean McGee, Alessia Moretti, Marco Gullieuszik, Alexander Drabent

Abstract: We report on the serendipitous discovery of an unprecedented interaction between the radio lobe of a radio galaxy and a spiral galaxy. The discovery was made thanks to LOFAR observations at 144 MHz of the galaxy cluster Abell 160 ($z=0.04317$) provided by the LOFAR Two-metre Sky Survey. The new low-frequency observations revealed that one of the radio plumes of the central galaxy GIN 049 overlaps with the spiral galaxy JO36. Previous studies carried out with MUSE revealed that the warm ionized gas in the disk of JO36, traced by the H$\alpha$ emission, is severely truncated with respect to the stellar disk. We further explore this unique system by including new uGMRT observations at 675 MHz to map the spectral index. The emerging scenario is that JO36 has interacted with the radio plume in the past 200-500 Myr. The encounter resulted in a positive feedback event for JO36 in the form of a star formation rate burst of $\sim14$ $M_\odot$ yr$^{-1}$. In turn, the galaxy passage left a trace in the radio-old plasma by re-shaping the old relativistic plasma via magnetic draping.

2.Polarized thermal emission from dust in a galaxy at redshift 2.6

Authors:J. E. Geach Hertfordshire, E. Lopez-Rodriguez KIPAC, Stanford, M. J. Doherty Hertfordshire, Jianhang Chen ESO, R. J. Ivison ESO, ASTRO 3D, DIAS, Edinburgh, G. J. Bendo Manchester, S. Dye Nottingham, K. E. K. Coppin Hertfordshire

Abstract: Magnetic fields are fundamental to the evolution of galaxies, playing a key role in the astrophysics of the interstellar medium and star formation. Large-scale ordered magnetic fields have been mapped in the Milky Way and nearby galaxies, but it is not known how early in the Universe such structures form. Here we report the detection of linearly polarized thermal emission from dust grains in a strongly lensed, intrinsically luminous galaxy that is forming stars at a rate more than a thousand times that of the Milky Way at redshift 2.6, within 2.5 Gyr of the Big Bang. The polarized emission arises from the alignment of dust grains with the local magnetic field. The median polarization fraction is of order one per cent, similar to nearby spiral galaxies. Our observations support the presence of a 5 kiloparsec-scale ordered magnetic field with a strength of around 500uG or lower, orientated parallel to the molecular gas disk. This confirms that such structures can be rapidly formed in galaxies, early in cosmic history.

3.Combined model for $\rm ^{15}N$, $\rm ^{13}C$, and spin-state chemistry in molecular clouds

Authors:O. Sipilä, L. Colzi, E. Roueff, P. Caselli, F. Fontani, E. Wirström

Abstract: We present a new gas-grain chemical model for the combined isotopic fractionation of carbon and nitrogen in molecular clouds, in which the isotope chemistry of carbon and nitrogen is coupled with a time-dependent description of spin-state chemistry. We updated the rate coefficients of some isotopic exchange reactions considered in the literature, and present here a set of new exchange reactions involving molecules substituted in $\rm ^{13}C$ and $\rm ^{15}N$ simultaneously. We apply the model to a series of zero-dimensional simulations representing a set of physical conditions across a prototypical prestellar core, exploring the deviations of the isotopic abundance ratios in the various molecules from the elemental isotopic ratios as a function of physical conditions and time. We find that the $\rm ^{12}C/^{13}C$ ratio can deviate from the elemental ratio by up to a factor of several depending on the molecule, and that there are highly time-dependent variations in the ratios. The $\rm HCN/H^{13}CN$ ratio, for example, can obtain values of less than 10 depending on the simulation time. The $\rm ^{14}N/^{15}N$ ratios tend to remain close to the assumed elemental ratio within $\sim$ ten per cent, with no clear trends as a function of the physical conditions. Abundance ratios between $\rm ^{13}C$-containing molecules and $\rm ^{13}C$+$\rm ^{15}N$-containing molecules show somewhat increased levels of fractionation due to the newly included exchange reactions, though still remaining within a few tens of per cent of the elemental $\rm ^{14}N/^{15}N$ ratio. Our results imply the existence of gradients in isotopic abundance ratios across prestellar cores, suggesting that detailed simulations are required to interpret observations of isotopically substituted molecules correctly, especially given that the various isotopic forms of a given molecule do not necessarily trace the same gas layers.

4.MeerKAT HI line observations of the nearby interacting galaxy pair NGC 1512/1510

Authors:E. Elson, M. Głowacki, R. Deane, N. Isaacs, X. Ndaliso

Abstract: We present MeerKAT HI line observations of the nearby interacting galaxy pair NGC 1512/1510. The MeerKAT data yield high-fidelity image sets characterised by an excellent combination of high angular resolution (~20") and and sensitivity (~0.08 Msun/pc^2), thereby offering the most detailed view of this well-studied system's neutral atomic hydrogen content, especially the HI co-located with the optical components of the galaxies. The stellar bulge and bar of NGC 1512 are located within a central HI depression where surface densities fall below 1 Msun/pc^2, while the galaxy's starburst ring coincides with a well-defined HI annulus delimited by a surface density of 3 Msun/pc^2. In stark contrast, the star-bursting companion, NGC 1510, has its young stellar population precisely matched to the highest HI over-densities we measure (~12.5 Msun/pc^2). The improved quality of the MeerKAT data warrants the first detailed measurements of the lengths and masses of the system's tidally-induced HI arms. We measure the longest of the two prominent HI arms to extend over ~27 kpc and to contain more than 30% of the system's total HI mass. We quantitatively explore the spatial correlation between HI and far-ultraviolet flux over a large range of HI mass surface densities spanning the outer disk. The results indicate the system's HI content to play an important role in setting the pre-conditions required for wide-spread, high-mass star formation. This work serves as a demonstration of the remarkable efficiency and accuracy with which MeerKAT can image nearby systems in HI line emission.

5.Forgotten treasures in the HST/FOC UV imaging polarimetric archives of active galactic nuclei. I. Pipeline and benchmarking against NGC~1068 and exploring IC~5063

Authors:Thibault Barnouin Observatoire Astronomique de Strasbourg, Université de Strasbourg, France, Frédéric Marin Observatoire Astronomique de Strasbourg, Université de Strasbourg, France, Enrique Lopez-Rodriguez Kavli Institute for Particle Astrophysics and Cosmolog, Stanford University, USA, Léo Huber Observatoire Astronomique de Strasbourg, Université de Strasbourg, France, Makoto Kishimoto Department of Astrophysics & Atmospheric Sciences, Kyoto Sangyo University, Japan

Abstract: Over its 13 years of operation (1990 -- 2002), the Faint Object Camera (FOC) on board the Hubble Space Telescope (HST) observed 26 individual active galactic nuclei (AGNs) in ultraviolet (UV) imaging polarimetry. However, not all of the observations have been reduced and analyzed or set within a standardized framework. We plan to reduce and analyze the AGN observations that have been neglected in the FOC archives using a consistent, novel, and open-access reduction pipeline of our own. We then extend the method to the full AGN sample, thus leading to potential discoveries in the near future. We developed a new pipeline in Python that will be able to reduce all the FOC observations in imaging polarimetry in a homogeneous way. Most of the previously published reduced observations are dispersed throughout the literature, with the range of different analyses and approaches making it difficult to fully interpret the FOC AGN sample. By standardizing the method, we have enabled a coherent comparison among the different observational sets. In this first paper of a series exploring the full HST/FOC AGN sample, we present an exhaustively detailed account of how to properly reduce the observational data. Current progress in data-analysis is implemented in and has provided state-of-the-art UV polarimetric maps. We compare our new maps to the benchmark AGN case of NGC~1068 and successfully reproduce the main results previously published, while pushing the polarimetric exploration of this AGN futher, thanks to a finer resolution and a higher signal-to-noise ratio (S/N) than previously reported. We also present, for the first time, an optical polarimetric map of the radio-loud AGN IC~5063 and we examine the complex interactions between the AGN outflows and the surrounding interstellar medium (ISM).

6.Estimating stellar population and emission line properties in S-PLUS galaxies

Authors:J. Thainá-Batista, R. Cid Fernandes, F. R. Herpich, C. Mendes de Oliveira, A. Werle, L. Espinosa, A. Lopes, A. V. Smith Castelli, L. Sodré, E. Telles, A. Kanaan, T. Ribeiro, W. Schoenell

Abstract: We present tests of a new method to simultaneously estimate stellar population and emission line (EL) properties of galaxies out of S-PLUS photometry. The technique uses the AlStar code, updated with an empirical prior which greatly improves its ability to estimate ELs using only the survey's 12 bands. The tests compare the output of (noise-perturbed) synthetic photometry of SDSS galaxies to properties derived from previous full spectral fitting and detailed EL analysis. For realistic signal-to-noise ratios, stellar population properties are recovered to better than 0.2 dex in masses, mean ages, metallicities and $\pm 0.2$ mag for the extinction. More importantly, ELs are recovered remarkably well for a photometric survey. We obtain input $-$ output dispersions of 0.05--0.2 dex for the equivalent widths of $[\mathrm{O}\,\rm{II}]$, $[\mathrm{O}\,\rm{III}]$, H$\beta$, H$\alpha$, $[\mathrm{N}\,\rm{II}]$, and $[\mathrm{S}\,\rm{II}]$, and even better for lines stronger than $\sim 5$ $\mathring{A}$. These excellent results are achieved by combining two empirical facts into a prior which restricts the EL space available for the fits: (1) Because, for the redshifts explored here, H$\alpha$ and $[\mathrm{N}\,\rm{II}]$ fall in a single narrow band (J0660), their combined equivalent width is always well recovered, even when $[\mathrm{N}\,\rm{II}]$/H$\alpha$ is not. (2) We know from SDSS that $W_{H\alpha+[\mathrm{N}\,\rm{II}]}$ correlates with $[\mathrm{N}\,\rm{II}]$/H$\alpha$, which can be used to tell if a galaxy belongs to the left or right wings in the classical BPT diagnostic diagram. Example applications to integrated light and spatially resolved data are also presented, including a comparison with independent results obtained with MUSE-based integral field spectroscopy.

7.New insight on the nature of cosmic reionizers from the CEERS survey

Authors:S. Mascia, L. Pentericci, A. Calabrò, P. Santini, L. Napolitano, P. Arrabal Haro, M. Castellano, M. Dickinson, P. Ocvirk, J. S. W. Lewis, R. Amorín, M. Bagley, R. N. J. Cleri, L. Costantin, A. Dekel, S. L. Finkelstein, A. Fontana, M. Giavalisco, N. A. Grogin, N. P. Hathi, M. Hirschmann, B. W. Holwerda, I. Jung, J. S. Kartaltepe, A. M. Koekemoer, R. A. Lucas, C. Papovich, P. G. Pérez-González, N. Pirzkal, J. R. Trump, S. M. Wilkins, L. Y. A. Yung

Abstract: The Epoch of Reionization (EoR) began when galaxies grew in abundance and luminosity, so their escaping Lyman continuum (LyC) radiation started ionizing the surrounding neutral intergalactic medium (IGM). Despite significant recent progress, the nature and role of cosmic reionizers are still unclear: in order to define them, it would be necessary to directly measure their LyC escape fraction ($f_{esc}$). However, this is impossible during the EoR due to the opacity of the IGM. Consequently, many efforts at low and intermediate redshift have been made to determine measurable indirect indicators in high-redshift galaxies so that their $f_{esc}$ can be predicted. This work presents the analysis of the indirect indicators of 62 spectroscopically confirmed star-forming galaxies at $6 \leq z \leq 9$ from the Cosmic Evolution Early Release Science (CEERS) survey, combined with 12 sources with public data from other JWST-ERS campaigns. From the NIRCam and NIRSpec observations, we measured their physical and spectroscopic properties. We discovered that on average $6<z<9$ star-forming galaxies are compact in the rest-frame UV ($r_e \sim $ 0.4 kpc), are blue sources (UV-$\beta$ slope $\sim $ -2.17), and have a predicted $f_{esc}$ of about 0.13. A comparison of our results to models and predictions as well as an estimation of the ionizing budget suggests that low-mass galaxies with UV magnitudes fainter than $M_{1500} = -18$ that we currently do not characterize with JWST observations probably played a key role in the process of reionization.

8.Ciii] λ1909 emission as an alternative to Lyα in the reionization era: the dependence of Ciii] and Lyα at 3 < z < 4 from the VANDELS survey

Authors:Mark H Cunningham University College London, Aayush Saxena University College London University of Oxford, Richard S Ellis University College London, Laura Pentricci INAF

Abstract: Ciii]{\lambda}{\lambda}1907, 1909 doublet emission line is a valuable tool for exploring early star-forming galaxies. It has been proposed as a potential alternative to the diminishing Ly{\alpha}{\lambda}1215.7 line for tracing galaxies during the Epoch of Reionization. In this study, we investigate the utility of the Ciii] line as a proxy for Ly{\alpha} in the reionization era by comparing the equivalent widths (EW) and velocity offsets of both emission lines. Our analysis focuses on star-forming galaxies at z \sim 3 - 4 from the VANDELS survey. We examined the spectra of 773 objects, identifying the rest-frame UV line Ciii]. Subsequently, we measured the EW of Ciii], Ly{\alpha}, and Heii. For objects displaying both Ciii] and Ly{\alpha} emission, the Ly{\alpha} velocity offsets was calculated. After removing 10 potential AGNs from our analysis, we detected Ciii] emission in 280/773 galaxies, with 139 receiving the highest confidence rating. The EW(Ciii]) had an average \sim 6 {\AA}, while EW(Ly{\alpha}) had an average \sim 18 {\AA}. Among the subset that showed both Ciii] and Ly{\alpha} (52/139), the average EW(Ciii]) was \sim 5 {\AA}, higher than those without Ly{\alpha} (EW(Ciii]) \sim 3 {\AA}). Additionally, all 52 galaxies in the Ciii] and Ly{\alpha} subset displayed a velocity shift ({\Delta}v_{Ly{\alpha}}), with average offset 533 km/s. This expanded dataset provides valuable insights, including a positive correlation between EW(Ciii]) and EW(Ly{\alpha}), confirming earlier findings. Furthermore, we report a promising anti-correlation between EW(Ciii]) and {\Delta}v_{Ly{\alpha}}, which may serve as a tool for inferring Ly{\alpha} properties and potentially detecting ionized bubbles at z \gt 6.

9.Possible Extragalactic Origins of Five LMC Globular Clusters: Proper Motion Deviations in Gaia DR3

Authors:Tamojeet Roychowdhury, Navdha Bhalla

Abstract: We use kinematic data of proper motions from Gaia of forty-two globular and open clusters from Large Magellanic Cloud (LMC) to explore the possibility of them having extragalactic origins. We find the difference between the proper motions of cluster stars and a surrounding patch of young LMC stars in each case. We find five globular clusters towards the north-east showing a high difference (> 0.11 mas/yr, or > 25 km/s). We also examine the statistical significance of this difference taking into account both measurement errors of cluster and surrounding stars as well as inherent dispersion of stellar motions in the local galactic environment. The five globular clusters (NGC 2005, NGC 2210, NGC 1978, Hodge 3 and Hodge 11) have mean proper motions that lie outside the 85% confidence interval of the mean of surrounding young stars, with a clear outlier (NGC 1978 outside 99.96% confidence) whose difference cannot be accounted for by statistical noise. A young cluster (NGC 2100) also fitting the criteria is ruled out owing to contrary evidence from literature. This indicates a possible interaction with a dwarf galaxy resulting in the accretion/disruption in path of the five globular clusters, or possibly one or more past merger(s) of smaller galaxy/galaxies with LMC from its north-eastern region. This direction also coincides with the location of Tarantula Nebula, suggesting the possibility of the interaction event or merger having triggered its star formation activity.

10.Quenching massive galaxies across cosmic time with the semi-analytic model SHARK v2.0

Authors:Claudia D. P. Lagos International Centre for Radio Astronomy Research ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions, ASTRO 3D Cosmic Dawn Center, Matias Bravo, Rodrigo Tobar, Danail Obreschkow, Chris Power, Aaron S. G. Robotham, Katy L. Proctor, Samuel Hansen, Angel Chandro-Gomez, Julian Carrivick

Abstract: We introduce version 2.0 of the SHARK semi-analytic model of galaxy formation after many improvements to the physics included. The most significant being: (i) a model describing the exchange of angular momentum (AM) between the interstellar medium and stars; (ii) a new active galactic nuclei feedback model which has two modes, a quasar and a radio mode, with the radio mode tied to the jet energy production; (iii) a model tracking the development of black hole (BH) spins; (iv) more sophisticated modelling of environmental effects on satellite galaxies; and (v) automatic parameter exploration using Particle Swarm Optimisation. We focus on two timely research topics: the structural properties of galaxies and the quenching of massive galaxies. For the former, SHARK v2.0 is capable of producing a more realistic stellar size-mass relation with a plateau marking the transition from disk- to bulge-dominated galaxies, and scaling relations between specific AM and mass that agree well with observations. For the quenching of massive galaxies, SHARK v2.0 produces massive galaxies that are more quenched than the previous version, reproducing well the observed relations between star formation rate (SFR) and stellar mass, and specific SFR and BH mass at $z=0$. SHARK v2.0 produces a number density of massive-quiescent galaxies >1dex higher than the previous version, in good agreement with JWST observations at $z\le 5$; predicts a stellar mass function of passive galaxies in reasonably good agreement with observations at $0.5<z<5$; and environmental quenching to already be effective at $z=5$.

11.De-noising of galaxy optical spectra with autoencoders

Authors:M. Scourfield, A. Saintonge, D. de Mijolla, S. Viti

Abstract: Optical spectra contain a wealth of information about the physical properties and formation histories of galaxies. Often though, spectra are too noisy for this information to be accurately retrieved. In this study, we explore how machine learning methods can be used to de-noise spectra and increase the amount of information we can gain without having to turn to sample averaging methods such as spectral stacking. Using machine learning methods trained on noise-added spectra - SDSS spectra with Gaussian noise added - we investigate methods of maximising the information we can gain from these spectra, in particular from emission lines, such that more detailed analysis can be performed. We produce a variational autoencoder (VAE) model, and apply it on a sample of noise-added spectra. Compared to the flux measured in the original SDSS spectra, the model values are accurate within 0.3-0.5 dex, depending on the specific spectral line and S/N. Overall, the VAE performs better than a principle component analysis (PCA) method, in terms of reconstruction loss and accuracy of the recovered line fluxes. To demonstrate the applicability and usefulness of the method in the context of large optical spectroscopy surveys, we simulate a population of spectra with noise similar to that in galaxies at $z = 0.1$ observed by the Dark Energy Spectroscopic Instrument (DESI). We show that we can recover the shape and scatter of the MZR in this "DESI-like" sample, in a way that is not possible without the VAE-assisted de-noising.

12.The viability of low-mass subhaloes as targets for gamma-ray dark matter searches

Authors:Alejandra Aguirre-Santaella, Miguel A. Sánchez-Conde

Abstract: In this work, we investigate the discovery potential of low-mass Galactic dark matter (DM) subhaloes for indirect searches of DM. We use data from the Via Lactea II (VL-II) N-body cosmological simulation, which resolves subhaloes down to $\mathcal{O}(10^4)$ solar masses and it is thus ideal for this purpose. First, we characterize the abundance, distribution and structural properties of the VL-II subhalo population in terms of both subhalo masses and maximum circular velocities. Then, we repopulate the original simulation with millions of subhaloes of masses down to about five orders of magnitude below the minimum VL-II subhalo mass (more than one order of magnitude in velocities). We compute subhalo DM annihilation astrophysical "J-factors" and angular sizes for the entire subhalo population, by placing the Earth at a random position but at the right galactocentric distance in the simulation. Thousands of these realizations are generated in order to obtain statistically meaningful results. We find that some nearby low-mass Galactic subhaloes, not massive enough to retain stars or gas, may indeed yield DM annihilation fluxes comparable to those expected from other, more massive and acknowledgeable DM targets like dwarf satellite galaxies. Typical angular sizes are of the order of the degree, thus subhaloes potentially appearing as extended sources in gamma-ray telescopes, depending on instrument angular resolution and sensitivity. Our work shows that low-mass Galactic subhaloes with no visible counterparts are expected to play a relevant role in current and future indirect DM search searches and should indeed be considered as excellent DM targets.

13.Gas Kinematics in the Magellanic-Type Galaxy NGC 7292

Authors:A. S. Gusev, A. V. Moiseev, S. G. Zheltoukhov

Abstract: The paper presents results of studying the kinematics of the ionized gas in the galaxy of the Large Magellanic Cloud type NGC 7292 obtained with the 2.5-m telescope of the Caucasian Mountain Observatory (CMO SAI MSU) and the 6-m BTA telescope of the Special Astrophysical Observatory (SAO RAS). Analysis of the velocity fields of the ionized and neutral hydrogen showed that the kinematic center of NGC 7292 located at the center of the bar, northwest of the photometric center of the galaxy (the southeastern end of the bar) previously taken as the center of NGC 7292. In addition to the circular rotation of the gas, the radial motions associated with the bar play a significant role in the kinematics of the disk. The observed perturbations of the gaseous-disk kinematics induced by the ongoing star formation do not exceed those caused by the bar. It is possible that part of the non-circular motions (at the southeastern end of the bar which is the brightest HII region) may be related to the effects of the capture of a dwarf companion or a gaseous cloud.

14.A morphological segmentation approach to determining bar lengths

Authors:Mitchell K. Cavanagh, Kenji Bekki, Brent A. Groves

Abstract: Bars are important drivers of galaxy evolution, influencing many physical processes and properties. Characterising bars is a difficult task, especially in large-scale surveys. In this work, we propose a novel morphological segmentation technique for determining bar lengths based on deep learning. We develop U-Nets capable of decomposing galaxy images into pixel masks highlighting the regions corresponding to bars and spiral arms. We demonstrate the versatility of this technique through applying our models to galaxy images from two different observational datasets with different source imagery, and to RGB colour and monochromatic galaxy imaging. We apply our models to analyse SDSS and Subaru HSC imaging of barred galaxies from the NA10 and SAMI catalogues in order to determine the dependence of bar length on stellar mass, morphology, redshift and the spin parameter proxy $\lambda_{R_e}$. Based on the predicted bar masks, we show that the relative bar scale length varies with morphology, with early type galaxies hosting longer bars. While bars are longer in more massive galaxies in absolute terms, relative to the galaxy disc they are actually shorter. We also find that the normalised bar length decreases with increasing redshift, with bars in early-type galaxies exhibiting the strongest rate of decline. We show that it is possible to distinguish spiral arms and bars in monochrome imaging, although for a given galaxy the estimated length in monochrome tends to be longer than in colour imaging. Our morphological segmentation technique can be efficiently applied to study bars in large-scale surveys and even in cosmological simulations.

15.B/PS bulges and barlenses from a kinematic viewpoint. I

Authors:Daria Zakharova, Iliya S. Tikhonenko, Natalia Ya. Sotnikova, Anton A. Smirnov

Abstract: A significant part of barred disc galaxies exhibits boxy/peanut-shaped structures (B/PS bulges) at high inclinations. Another structure also associated with the bar is a barlens, often observed in galaxies in a position close to face-on. At this viewing angle, special kinematic tests are required to detect a 3D extension of the bars in the vertical direction (B/PS bulges). We use four pure $N$-body models of galaxies with B/PS bulges, which have different bar morphology from bars with barlenses to the so-called face-on peanut bars. We analyse the kinematics of our models to establish how the structural features of B/PS bulges manifest themselves in the kinematics for galaxies at intermediate inclinations and whether these features are related to the barlenses. We apply the dissection of the bar into different orbital groups to determine which of them are responsible for the features of the LOSVD (line-of-sight velocity distribution), i.e., for the deep minima of the $h_4$ parameter along the major axis of the bar. As a result, we claim that for our models at the face-on position, the kinematic signatures of a `peanut' indeed track the vertical density distribution features. We conclude that orbits responsible for such kinematic signatures differ from model to model. We pay special attention to the barlens model. We show that orbits assembled into barlens are not responsible for the kinematic signatures of B/PS bulges. The results presented in this work are applicable to the interpretation of IFU observations of real galaxies.

16.A Photon Burst Clears the Earliest Dusty Galaxies: Modelling Dust in High-redshift Galaxies from ALMA to JWST

Authors:Daichi Tsuna, Yurina Nakazato, Tilman Hartwig

Abstract: The generation and evolution of dust in galaxies are important tracers for star formation, and can characterize the rest-frame ultraviolet to infrared emission from the galaxies. In particular understanding dust in high-redshift galaxies are important for observational cosmology, as they would be necessary to extract information on star formation in the early universe. We update the public semi-analytical model A-SLOTH (Ancient Stars and Local Observables by Tracing Halos) to model the evolution of dust, focusing on high-redshift star-forming galaxies with stellar masses of $\sim 10^8$--$10^{10}M_\odot$ observed by ALMA ($z\approx 7$) and JWST ($z\approx 11$). We find that these galaxies should qualitatively differ in their star formation properties; while the samples in ALMA are explained by dust growth in normal star-forming galaxies, the lack of dust in the samples by JWST requires dust ejection by radiation pressure due to recent highly efficient star-formation within a few 10 Myr, with order 100 times higher efficiency than normal galaxies calibrated by A-SLOTH. Depending on where the JWST galaxies locate on the luminosity function, their bursty star formation histories inferred from our model can have impacts for rates of star formation, supernova explosion, stellar feedback, and detectability of dusty, mature galaxies in the very early universe.

1.Discovery of compact disc Galaxies with High Surface Brightness in the Sloan Digital Sky Survey

Authors:Cheng-Yu Chen, Chorng-Yuan Hwang

Abstract: Compact disc galaxies (CDGs) with high surface brightness were identified in the Sloan Digital Sky Survey (SDSS) data. We determined the surface profiles of the CDGs and compared them to those of normal-sized disk galaxies (NDGs). The CDGs have higher central brightness and older stellar age than the NDGs. Furthermore, the brightness profiles of the CDGs fit a S{\'e}rsic model with $n \approx 2.11$ and have a zero $g^{\prime}-r^{\prime}$ color gradient on average. By contrast, the NDGs fit an exponential profile and have a negative color gradient on average. These results indicate that the structure and stellar population of the CDGs and NDGs differ. We suggest that the CDGs are ancient galaxies in the quenching phase following the initial central starburst.

2.Ultraluminous Quasars At High Redshift Show Evolution In Their Radio-Loudness Fraction In Both Redshift And Ultraviolet Luminosity

Authors:Philip Lah, Christopher A. Onken, Ray P. Norris, Francesco D'Eugenio

Abstract: We take a sample of 94 ultraluminous, optical quasars from the search of over 14,486 deg^2 by Onken et al. 2022 in the range 4.4<redshift<5.2 and match them against the Rapid ASKAP Continuum Survey (RACS) observed on the Australian Square Kilometre Array Pathfinder (ASKAP). From this most complete sample of the bright end of the redshift ~5 quasar luminosity function, there are 10 radio continuum detections of which 8 are considered radio-loud quasars. The radio-loud fraction for this sample is 8.5 \pm 2.9 per cent. Jiang et al. 2007 found that there is a decrease in the radio-loud fraction of quasars with increasing redshift and an increase with increasing absolute magnitude at rest frame 2500 Angstroms. We show that the radio-loud fraction of our quasar sample is consistent with that predicted by Jiang et al. 2007, extending their result to higher redshifts.

3.Gas phase Elemental abundances in Molecular cloudS (GEMS). IX. Deuterated compounds of H2S in starless cores

Authors:Marina Rodríguez-Baras, Gisela Esplugues, Asunción Fuente, Silvia Spezzano, Paola Caselli, Jean-Christophe Loison, Evelyne Roueff, David Navarro-Almaida, Rafael Bachiller, Rafael Martín-Doménech, Izaskun Jiménez-Serra, Leire Beitia-Antero, Romane Le Gal

Abstract: H2S is thought to be the main sulphur reservoir in the ice, being therefore a key molecule to understand sulphur chemistry in the star formation process and to solve the missing sulphur problem. The H2S deuterium fraction can be used to constrain its formation pathways. We investigate for the first time the H2S deuteration in a large sample of starless cores (SC). We use observations of the GEMS IRAM 30m Large Program and complementary IRAM 30m observations. We consider a sample of 19 SC in Taurus, Perseus, and Orion, detecting HDS in 10 and D2S in five. The H2S single and double deuterium fractions are analysed with regard to their relation with the cloud physical parameters, their comparison with other interstellar sources, and their comparison with deuterium fractions in early stage star-forming sources of c-C3H2, H2CS, H2O, H2CO, and CH3OH. We obtain a range of X(HDS)/X(H2S)~0.025-0.2 and X(D2S)/X(HDS)~0.05-0.3. H2S single deuteration shows an inverse relation with the cloud kinetic temperature. H2S deuteration values in SC are similar to those observed in Class 0. Comparison with other molecules in other sources reveals a general trend of decreasing deuteration with increasing temperature. In SC and Class 0 objects H2CS and H2CO present higher deuteration fractions than c-C3H2, H2S, H2O, and CH3OH. H2O shows single and double deuteration values one order of magnitude lower than those of H2S and CH3OH. Differences between c-C3H2, H2CS and H2CO deuterium fractions and those of H2S, H2O, and CH3OH are related to deuteration processes produced in gas or solid phases, respectively. We interpret the differences between H2S and CH3OH deuterations and that of H2O as a consequence of differences on the formation routes in the solid phase, particularly in terms of the different occurrence of the D-H and H-D substitution reactions in the ice, together with the chemical desorption processes.

4.The evolution of the cold gas fraction in nearby clusters ram-pressure stripped galaxies

Authors:Alessia Moretti, Paolo Serra, Cecilia Bacchini, Rosita Paladino, Mpati Ramatsoku, Bianca M. Poggianti, Benedetta Vulcani, Tirna Deb, Marco Gullieuszik, Jacopo Fritz, Anna Wolter

Abstract: Cluster galaxies are affected by the surrounding environment, which influences, in particular, their gas, stellar content and morphology. In particular, the ram-pressure exerted by the intracluster medium promotes the formation of multi-phase tails of stripped gas detectable both at optical wavelengths and in the sub-mm and radio regimes, tracing the cold molecular and atomic gas components, respectively. In this work we analyze a sample of sixteen galaxies belonging to clusters at redshift $\sim 0.05$ showing evidence of an asymmetric HI morphology (based on MeerKAT observations) with and without a star forming tail. To this sample we add three galaxies with evidence of a star forming tail and no HI detection. Here we present the galaxies $\rm H_{2}$ gas content from APEX observations of the CO(2-1) emission. We find that in most galaxies with a star forming tail the $\rm H_{2}$ global content is enhanced with respect to undisturbed field galaxies with similar stellar masses, suggesting an evolutionary path driven by the ram-pressure stripping. As galaxies enter into the clusters their HI is displaced but also partially converted into $\rm H_{2}$, so that they are $\rm H_{2}$ enriched when they pass close to the pericenter, i. e. when they develop the star forming tails that are visible in UV/B broad bands and in H$\alpha$ emission. An inspection of the phase-space diagram for our sample suggests an anticorrelation between the HI and $\rm H_{2}$ gas phases as galaxies fall into the cluster potential. This peculiar behaviour is a key signature of the ram-pressure stripping in action.

5.Faint [CI](1-0) emission in z $\sim$ 3.5 radio galaxies

Authors:S. Kolwa, C. De Breuck, J. Vernet, D. Wylezalek, W. Wang, G. Popping, A. W. S. Man, C. M. Harrison, P. Andreani

Abstract: We present Atacama Large Millimeter/sub-millimeter Array (ALMA) neutral carbon, [C I](1-0), line observations that probe molecular hydrogen gas (H$_2$) within seven radio galaxies at $z = 2.9 - 4.5$ surrounded by extended ($\gtrsim100$ kpc) Ly-$\alpha$ nebulae. We extract [C I](1-0) emission from the radio-active galactic nuclei (AGN) host galaxies whose positions are set by near-infrared detections and radio detections of the cores. Additionally, we place constraints on the galaxies' systemic redshifts via He II $\lambda$1640 lines seen with the Multi-Unit Spectroscopic Explorer (MUSE). We detect faint [C I] emission in four out of seven sources. In two of these galaxies, we discover narrow line emission of full width at half maximum $\lesssim100$ km s$^{-1}$ which may trace emission from bright kpc-scale gas clouds within the ISM. In the other two [C I]-detected galaxies, line dispersions range from $\sim100 - 600$ km s$^{-1}$ and may be tracing the rotational component of the cold gas. Overall, the [C I] line luminosities correspond to H$_2$ masses of M$_{\rm H_2,[C I]} \simeq (0.5 - 3) \times 10^{10} M_\odot$ for the detections and M$_{H_2,[C I]} < 0.65 \times 10^{10} M_\odot$ for the [C I] non-detections in three out of seven galaxies within the sample. The molecular gas masses in our sample are relatively low in comparison to previously reported measures for similar galaxies which are M$_{H_2,[C I]} \simeq (3 - 4) \times 10^{10}.$ Our results imply that the observed faintness in carbon emission is representative of a decline in molecular gas supply from previous star-formation epochs and/or a displacement of molecular gas from the ISM due to jet-powered outflows.

6.FAUST X: Formaldehyde in the Protobinary System [BHB2007] 11: Small Scale Deuteration

Authors:Lucy Evans, Charlotte Vastel, Francisco Fontani, Jaime Pineda, Izaskun Jiménez-Serra, Felipe Alves, Takeshi Sakai, Mathilde Bouvier, Paola Caselli, Cecilia Ceccarelli, Claire Chandler, Brian Svoboda, Luke Maud, Claudio Codella, Nami Sakai, Romane Le Gal, Ana López-Sepulcre, George Moellenbrock, Satoshi Yamamoto

Abstract: Context. Deuterium in H-bearing species is enhanced during the early stages of star formation, however, only a small number of high spatial resolution deuteration studies exist towards protostellar objects, leaving the small-scale structures unrevealed and understudied. Aims. We aim to constrain the deuterium fractionation ratios in a Class 0/I protostellar object in formaldehyde (H2CO), which has abundant deuterated isotopologues in this environment. Methods. We observed the Class 0/I protobinary system [BHB2007] 11, whose emission components are embedded in circumstellar disks that have radii of 2-3 au, using ALMA within the context of the Large Program FAUST. The system is surrounded by a complex filamentary structure connecting to the larger circumbinary disk. In this work we present the first study of formaldehyde D-fractionation towards this source with detections of H2CO 3(0,3)-2(0,2), combined with HDCO 4(2,2)-3(2,1), HDCO 4(1,4)-3(1,3) and D2CO 4(0,4)-3(0,3). These observations enable multiple velocity components associated with the methanol hotspots also uncovered by FAUST data, as well as the external envelope, to be resolved. In addition, based on the kinematics seen in the observations of the H2CO emission, we propose the presence of a second large scale outflow. Results. HDCO and D2CO are only found in the central regions of the core while H2CO is found more ubiquitously. From radiative transfer modelling, the column densities ranges found for H2CO, HDCO and D2CO are (3-8)x10$^{14}$ cm$^{-2}$, (0.8-2.9)x10$^{13}$ cm$^{-2}$ and (2.6-4.3)x10$^{12}$ cm$^{-2}$, respectively, yielding an average D/H ratio of 0.01-0.04. Following the results of kinematic modelling, the second large scale feature is inconsistent with a streamer-like nature and we thus tentatively conclude that the feature is an asymmetric molecular outflow launched by a wide-angle disk wind.

1.Strong [O III] λ5007 Compact Galaxies Identified from SDSS DR16 and Their Scaling Relations

Authors:Weiyu Ding, Hu Zou, Xu Kong, Yulong Gao, Fujia Li, Hongxin Zhang, Jiali Wang, Jie Song, Jipeng Sui, Jundan Nie, Suijian Xue, Weijian Guo, Yao Yao, Zhimin Zhou

Abstract: Green pea galaxies are a special class of star-forming compact galaxies with strong [O III]{\lambda}5007 and considered as analogs of high-redshift Ly{\alpha}-emitting galaxies and potential sources for cosmic reionization. In this paper, we identify 76 strong [O III]{\lambda}5007 compact galaxies at z < 0.35 from DR1613 of the Sloan Digital Sky Survey. These galaxies present relatively low stellar mass, high star formation rate, and low metallicity. Both star-forming main sequence relation (SFMS) and mass-metallicity relation (MZR) are investigated and compared with green pea and blueberry galaxies collected from literature. It is found that our strong [O III] {\lambda}5007 compact galaxies share common properties with those compact galaxies with extreme star formation and show distinct scaling relations in respect to those of normal star-forming galaxies at the same redshift. The slope of SFMS is higher, indicates that strong [O III]{\lambda}5007 compact galaxies might grow faster in stellar mass. The lower MZR implies that they may be less chemically evolved and hence on the early stage of star formation. A further environmental investigation confirms that they inhabit relatively low-density regions. Future largescale spectroscopic surveys will provide more details on their physical origin and evolution.

2.Influence of star-forming galaxy selection on the galaxy main sequence

Authors:W. J. Pearson, F. Pistis, M. Figueira, K. Małek, T. Moutard, D. Vergani, A. Pollo

Abstract: This work aims to determine how the galaxy main sequence (MS) changes using seven different commonly used methods to select the star-forming galaxies within VIPERS data over $0.5 \leq z < 1.2$. The form and redshift evolution of the MS will then be compared between selection methods. The star-forming galaxies were selected using widely known methods: a specific star-formation rate (sSFR), Baldwin, Phillips and Terlevich (BPT) diagram, 4000\AA\ spectral break (D4000) cut and four colour-colour cuts: NUVrJ, NUVrK, u-r, and UVJ. The main sequences were then fitted for each of the seven selection methods using a Markov chain Monte Carlo forward modelling routine, fitting both a linear main sequence and a MS with a high-mass turn-over to the star-forming galaxies. This was done in four redshift bins of $0.50 \leq z < 0.62$, $0.62 \leq z < 0.72$, $0.72 \leq z < 0.85$, and $0.85 \leq z < 1.20$. The slopes of all star-forming samples were found to either remain constant or increase with redshift, and the scatters were approximately constant. There is no clear redshift dependency of the presence of a high-mass turn-over for the majority of samples, with the NUVrJ and NUVrK being the only samples with turn-overs only at low redshift. No samples have turn-overs at all redshifts. Star-forming galaxies selected with sSFR and u-r are the only samples to have no high-mass turn-over in all redshift bins. The normalisation of the MS increases with redshift, as expected. The scatter around the MS is lower than the $\approx$0.3~dex typically seen in MS studies for all seven samples. The lack, or presence, of a high-mass turn-over is at least partially a result of the method used to select star-forming galaxies. However, whether a turn-over should be present or not is unclear.

3.GA-NIFS: JWST/NIRSpec IFU observations of HFLS3 reveal a dense galaxy group at z~6.3

Authors:G. C. Jones, H. Ubler, M. Perna, S. Arribas, A. J. Bunker, S. Carniani, S. Charlot, R. Maiolino, B. Rodriguez Del Pino, C. Willott, R. A. A. Bowler, T. Boker, A. J. Cameron, J. Chevallard, G. Cresci, M. Curti, F. D'Eugenio, N. Kumari, A. Saxena, J. Scholtz, G. Venturi, J. Witstok

Abstract: Massive, starbursting galaxies in the early Universe represent some of the most extreme objects in the study of galaxy evolution. One such source is HFLS3 (z~6.34), which was originally identified as an extreme starburst galaxy with mild gravitational magnification. Here, we present new observations of HFLS3 with the JWST/NIRSpec IFU in both low (PRISM/CLEAR; R~100) and high spectral resolution (G395H/290LP; R~2700), with high spatial resolution (~0.1") and sensitivity. Thanks to the combination of the NIRSpec data and a new lensing model with accurate spectroscopic redshifts, we find that the 3"x3" field is crowded, with a lensed arc (C, z=6.3425+/-0.0002), two galaxies to the south (S1 and S2, z=6.3592+/-0.0001), two galaxies to the west (W1, z=6.3550+/-0.0001; W2, z=6.3628+/-0.0001), and two low-redshift interlopers (G1, z=3.4806+/-0.0001; G2, z=2.00+/-0.01). We present spectral fits and morpho-kinematic maps for each bright emission line (e.g., [OIII]5007, Halpha, [NII]6584) from the R2700 data for all sources except G2. From a line ratio analysis, the galaxies in C are likely powered by star formation, while we cannot rule out or confirm the presence of AGN in the other high-redshift sources. We perform gravitational lens modelling, finding evidence for a two-source composition of the lensed central object and a comparable magnification factor (mu=2.1-2.4) to previous work. The projected distances and velocity offsets of each galaxy suggest that they will merge within the next ~1Gyr. Finally, we examine the dust extinction-corrected SFR of each z>6 source, finding that the total star formation (460+/-90 Msol/yr, magnification-corrected) is distributed across the six z~6.34-6.36 objects over a region of diameter ~11kpc. Altogether, this suggests that HFLS3 is not a single starburst galaxy, but instead is a merging system of star-forming galaxies in the Epoch of Reionization.

4.The Orion-Taurus ridge: a synchrotron radio loop at the edge of the Orion-Eridanus superbubble

Authors:Andrea Bracco, Marco Padovani, Juan D. Soler

Abstract: Large-scale synchrotron loops are recognized as the main source of diffuse radio-continuum emission in the Galaxy at intermediate and high Galactic latitudes. Their origin, however, remains rather unexplained. Using a combination of multi-frequency data in the radio band of total and polarized intensities, for the first time in this letter, we associate one arc -- hereafter, the Orion-Taurus ridge -- with the wall of the most prominent stellar-feedback blown shell in the Solar neighborhood, namely the Orion-Eridanus superbubble. We traced the Orion-Taurus ridge using 3D maps of interstellar dust extinction and column-density maps of molecular gas, $N_{\rm H_2}$. We found the Orion-Taurus ridge at a distance of 400\,pc, with a plane-of-the-sky extent of $180$\,pc. Its median $N_{\rm H_2}$ value is $(1.4^{+2.6}_{-0.6})\times 10^{21}$ cm$^{-2}$. Thanks to the broadband observations below 100 MHz of the Long Wavelength Array, we also computed the low-frequency spectral-index map of synchrotron emissivity, $\beta$, in the Orion-Taurus ridge. We found a flat distribution of $\beta$ with a median value of $-2.24^{+0.03}_{-0.02}$ that we interpreted in terms of depletion of low-energy ($<$ GeV) cosmic-ray electrons in recent supernova remnants ($10^5$ - $10^6$ yrs). Our results are consistent with plane-of-the-sky magnetic-field strengths in the Orion-Taurus ridge larger than a few tens of $\mu$G ($> 30 - 40 \,\mu$G). We report the first detection of diffuse synchrotron emission from cold-neutral, partly molecular, gas in the surroundings of the Orion-Eridanus superbubble. This observation opens a new perspective to study the multiphase and magnetized interstellar medium with the advent of future high-sensitivity radio facilities, such as the C-Band All-Sky Survey and the Square Kilometre Array.

5.Prospects for observing supermassive black hole binaries with the space-ground interferometer

Authors:A. M. Malinovsky Astro Space Center of P.N. Lebedev Physical Institute of RAS, Moscow, Russia, E. V. Mikheeva Astro Space Center of P.N. Lebedev Physical Institute of RAS, Moscow, Russia

Abstract: A list of candidates for \textit{supermassive binary black holes} (SMBBHs), compiled from available data on the variability in the optical range and the shape of the emission spectrum, is analysed. An artificial neural network is constructed to estimate the radiation flux at 240~GHz. For those candidate SMBBH for which the network building procedure was feasible, the criterion of the possibility of observing the source at the \textit{Millimetron Space Observatory} (MSO) was tested. The result is presented as a table of 17 candidate SMBBHs. Confirmation (or refutation) of the duality of these objects by means of observational data which could be commited on a space-ground interferometer with parameters similar to those of the MSO will be an important milestone in the development of the theory of galaxy formation.

6.PDRs4All II: JWST's NIR and MIR imaging view of the Orion Nebula

Authors:Emilie Habart, Els Peeters, Olivier Berné, Boris Trahin, Amélie Canin, Ryan Chown, Ameek Sidhu, Dries Van De Putte, Felipe Alarcón, Ilane Schroetter, Emmanuel Dartois, Sílvia Vicente, Alain Abergel, Edwin A. Bergin, Jeronimo Bernard-Salas, Christiaan Boersma, Emeric Bron, Jan Cami, Sara Cuadrado, Daniel Dicken, Meriem Elyajouri, Asunción Fuente, Javier R. Goicoechea, Karl D. Gordon, Lina Issa, Christine Joblin, Olga Kannavou, Baria Khan, Ozan Lacinbala, David Languignon, Romane Le Gal, Alexandros Maragkoudakis, Raphael Meshaka, Yoko Okada, Takashi Onaka, Sofia Pasquini, Marc W. Pound, Massimo Robberto, Markus Röllig, Bethany Schefter, Thiébaut Schirmer, Benoit Tabone, Alexander G. ~G. ~M. Tielens, Mark G. Wolfire, Marion Zannese, Nathalie Ysard, Marc-Antoine Miville-Deschenes, Isabel Aleman, Louis Allamandola, Rebecca Auchettl, Giuseppe Antonio Baratta, Salma Bejaoui, Partha P. Bera, John~H. ~Black, Francois~Boulanger, Jordy Bouwman, Bernhard Brandl, Philippe Brechignac, Sandra Brünken, Mridusmita Buragohain, rew Burkhardt, Alessandra Candian, Stéphanie Cazaux, Jose Cernicharo, Marin Chabot, Shubhadip Chakraborty, Jason Champion, Sean W. J. Colgan, Ilsa R. Cooke, Audrey Coutens, Nick L. J. Cox, Karine Demyk, Jennifer Donovan Meyer, Sacha Foschino, Pedro García-Lario, Lisseth Gavilan, Maryvonne Gerin, Carl A. Gottlieb, Pierre Guillard, Antoine Gusdorf, Patrick Hartigan, Jinhua He, Eric Herbst, Liv Hornekaer, Cornelia Jäger, Eduardo Janot-Pacheco, Michael Kaufman, Francisca Kemper, Sarah Kendrew, Maria S. Kirsanova, Pamela Klaassen, Sun Kwok, Álvaro Labiano, Thomas S. -Y. Lai, Timothy J. Lee, Bertrand Lefloch, Franck Le Petit, Aigen Li, Hendrik Linz, Cameron J. Mackie, Suzanne C. Madden, Joëlle Mascetti, Brett A. McGuire, Pablo Merino, Elisabetta R. Micelotta, Karl Misselt, Jon A. Morse, Giacomo Mulas, Naslim Neelamkodan, Ryou Ohsawa, Alain Omont, Roberta Paladini, Maria Elisabetta Palumbo, Amit Pathak, Yvonne J. Pendleton, Annemieke Petrignani, Thomas Pino, Elena Puga, Naseem Rangwala, Mathias Rapacioli, Alessandra Ricca, Julia Roman-Duval, Joseph~Roser, Evelyne Roueff, Gaël Rouillé, Farid Salama, Dinalva A. Sales, Karin Sandstrom, Peter Sarre, Ella Sciamma-O'Brien, Kris Sellgren, Sachindev S. Shenoy, David Teyssier, Richard D. Thomas, Aditya Togi, Laurent Verstraete, Adolf N. Witt, Alwyn Wootten, Henning Zettergren, Yong Zhang, Ziwei E. Zhang, Junfeng Zhen

Abstract: The JWST has captured the most detailed and sharpest infrared images ever taken of the inner region of the Orion Nebula, the nearest massive star formation region, and a prototypical highly irradiated dense photo-dissociation region (PDR). We investigate the fundamental interaction of far-ultraviolet photons with molecular clouds. The transitions across the ionization front (IF), dissociation front (DF), and the molecular cloud are studied at high-angular resolution. These transitions are relevant to understanding the effects of radiative feedback from massive stars and the dominant physical and chemical processes that lead to the IR emission that JWST will detect in many Galactic and extragalactic environments. Due to the proximity of the Orion Nebula and the unprecedented angular resolution of JWST, these data reveal that the molecular cloud borders are hyper structured at small angular scales of 0.1-1" (0.0002-0.002 pc or 40-400 au at 414 pc). A diverse set of features are observed such as ridges, waves, globules and photoevaporated protoplanetary disks. At the PDR atomic to molecular transition, several bright features are detected that are associated with the highly irradiated surroundings of the dense molecular condensations and embedded young star. Toward the Orion Bar PDR, a highly sculpted interface is detected with sharp edges and density increases near the IF and DF. This was predicted by previous modeling studies, but the fronts were unresolved in most tracers. A complex, structured, and folded DF surface was traced by the H2 lines. This dataset was used to revisit the commonly adopted 2D PDR structure of the Orion Bar. JWST provides us with a complete view of the PDR, all the way from the PDR edge to the substructured dense region, and this allowed us to determine, in detail, where the emission of the atomic and molecular lines, aromatic bands, and dust originate.

7.PDRs4All IV. An embarrassment of riches: Aromatic infrared bands in the Orion Bar

Authors:Ryan Chown, Ameek Sidhu, Els Peeters, Alexander G. G. M. Tielens, Jan Cami, Olivier Berne, Emilie Habart, Felipe Alarcon, Amelie Canin, Ilane Schroetter, Boris Trahin, Dries Van De Putte, Alain Abergel, Edwin A. Bergin, Jeronimo Bernard-Salas, Christiaan Boersma, Emeric Bron, Sara Cuadrado, Emmanuel Dartois, Daniel Dicken, Meriem El-Yajouri, Asuncion Fuente, Javier R. Goicoechea, Karl D. Gordon, Lina Issa, Christine Joblin, Olga Kannavou, Baria Khan, Ozan Lacinbala, David Languignon, Romane Le Gal, Alexandros Maragkoudakis, Raphael Meshaka, Yoko Okada, Takashi Onaka, Sofia Pasquini, Marc W. Pound, Massimo Robberto, Markus Rollig, Bethany Schefter, Thiebaut Schirmer, Silvia Vicente, Mark G. Wolfire, Marion Zannese, Isabel Aleman, Louis Allamandola, Rebecca Auchettl, Giuseppe Antonio Baratta, Salma Bejaoui, Partha P. Bera, John H. Black, Francois Boulanger, Jordy Bouwman, Bernhard Brandl, Philippe Brechignac, Sandra Brunken, Mridusmita Buragohain, Andrew Burkhardt, Alessandra Candian, Stephanie Cazaux, Jose Cernicharo, Marin Chabot, Shubhadip Chakraborty, Jason Champion, Sean W. J. Colgan, Ilsa R. Cooke, Audrey Coutens, Nick L. J. Cox, Karine Demyk, Jennifer Donovan Meyer, Sacha Foschino, Pedro Garcia-Lario, Lisseth Gavilan, Maryvonne Gerin, Carl A. Gottlieb, Pierre Guillard, Antoine Gusdorf, Patrick Hartigan, Jinhua He, Eric Herbst, Liv Hornekaer, Cornelia Jager, Eduardo Janot-Pacheco, Michael Kaufman, Francisca Kemper, Sarah Kendrew, Maria S. Kirsanova, Pamela Klaassen, Sun Kwok, Alvaro Labiano, Thomas S. -Y. Lai, Timothy J. Lee, Bertrand Lefloch, Franck Le Petit, Aigen Li, Hendrik Linz, Cameron J. Mackie, Suzanne C. Madden, Joelle Mascetti, Brett A. McGuire, Pablo Merino, Elisabetta R. Micelotta, Karl Misselt, Jon A. Morse, Giacomo Mulas, Naslim Neelamkodan, Ryou Ohsawa, Alain Omont, Roberta Paladini, Maria Elisabetta Palumbo, Amit Pathak, Yvonne J. Pendleton, Annemieke Petrignani, Thomas Pino, Elena Puga, Naseem Rangwala, Mathias Rapacioli, Alessandra Ricca, Julia Roman-Duval, Joseph Roser, Evelyne Roueff, Gael Rouillee, Farid Salama, Dinalva A. Sales, Karin Sandstrom, Peter Sarre, Ella Sciamma-O'Brien, Kris Sellgren, Sachindev S. Shenoy, David Teyssier, Richard D. Thomas, Aditya Togi, Laurent Verstraete, Adolf N. Witt, Alwyn Wootten, Henning Zettergren, Yong Zhang, Ziwei E. Zhang, Junfeng Zhen

Abstract: (Abridged) Mid-infrared observations of photodissociation regions (PDRs) are dominated by strong emission features called aromatic infrared bands (AIBs). The most prominent AIBs are found at 3.3, 6.2, 7.7, 8.6, and 11.2 $\mu$m. The most sensitive, highest-resolution infrared spectral imaging data ever taken of the prototypical PDR, the Orion Bar, have been captured by JWST. We provide an inventory of the AIBs found in the Orion Bar, along with mid-IR template spectra from five distinct regions in the Bar: the molecular PDR, the atomic PDR, and the HII region. We use JWST NIRSpec IFU and MIRI MRS observations of the Orion Bar from the JWST Early Release Science Program, PDRs4All (ID: 1288). We extract five template spectra to represent the morphology and environment of the Orion Bar PDR. The superb sensitivity and the spectral and spatial resolution of these JWST observations reveal many details of the AIB emission and enable an improved characterization of their detailed profile shapes and sub-components. While the spectra are dominated by the well-known AIBs at 3.3, 6.2, 7.7, 8.6, 11.2, and 12.7 $\mu$m, a wealth of weaker features and sub-components are present. We report trends in the widths and relative strengths of AIBs across the five template spectra. These trends yield valuable insight into the photochemical evolution of PAHs, such as the evolution responsible for the shift of 11.2 $\mu$m AIB emission from class B$_{11.2}$ in the molecular PDR to class A$_{11.2}$ in the PDR surface layers. This photochemical evolution is driven by the increased importance of FUV processing in the PDR surface layers, resulting in a "weeding out" of the weakest links of the PAH family in these layers. For now, these JWST observations are consistent with a model in which the underlying PAH family is composed of a few species: the so-called 'grandPAHs'.

8.On the accretion of a new group of galaxies onto Virgo: III. The stellar population radial gradients of dEs

Authors:Bahar Bidaran, Francesco La Barbera, Anna Pasquali, Glenn van de Ven, Reynier Peletier, Jesus Falcón-Barroso, Dimitri A. Gadotti, Agnieszka Sybilska, Eva K. Grebel

Abstract: Using MUSE data, we investigate the radial gradients of stellar population properties (namely age, [M/H], and the abundance ratio of $\alpha$ elements [$\alpha$/Fe]) for a sample of nine dwarf early-type (dE) galaxies with log(M$_{\star}$/M$_{\odot}$) $\sim$ 9.0 and an infall time onto the Virgo cluster of 2-3Gyr ago. We followed a similar approach as in Bidaran et al. (2022) to derive their stellar population properties and star formation histories (SFHs) through fitting observed spectral indices and full spectral fitting, respectively. We find that these nine dE galaxies have truncated [Mg/Fe]vs.[Fe/H] profiles than equally-massive Virgo dE galaxies with longer past infall times. Short profiles of three dE galaxies are the result of their intense star formation which has been quenched long before their accretion onto the Virgo cluster, possibly as a result of their group environment. In the remaining six dE galaxies, profiles mainly trace a recent episode of star burst within 0.4R$_{\rm e}$ which results in higher light-weighted [$\alpha$/Fe] values. The latter SFH peak can be due to ram pressure exerted by the Virgo cluster at the time of the accretion of the dE galaxies. Also, we show that younger, more metal-rich and less $\alpha$-enhanced stellar populations dominate their inner regions (i.e., < 0.4R$_{\rm e}$) resulting in mainly flat $\nabla_{\rm age}$, negative $\nabla_{\rm [M/H]}$ and positive $\nabla_{\rm [\alpha/Fe]}$. We find that with increasing log($\sigma_{\rm Re}$) of dE galaxies, $\nabla_{\rm age}$ and $\nabla_{\rm [\alpha/Fe]}$ flatten, and the latter correlation persists even after including early-type galaxies up to log($\sigma_{\rm Re}$ $\sim$ 2.5), possibly due to the more extended star formation activity in the inner regions of dEs, as opposed to more massive early-type galaxies.

9.VLBI Observations of a sample of Palomar-Green quasars II: characterising the parsec-scale radio emission

Authors:Ailing Wang, Tao An, Yingkang Zhang, Xiaopeng Cheng, Luis C. Ho, Kenneth I. Kellermann, Willem A. Baan

Abstract: This study uses multi-frequency Very Long Baseline Interferometry (VLBI) to study the radio emission from 10 radio-quiet quasars (RQQs) and four radio-loud quasars (RLQs). The diverse morphologies, radio spectra, and brightness temperatures observed in the VLBI images of these RQQs, together with the variability in their GHz spectra and VLBI flux densities, shed light on the origins of their nuclear radio emission. The total radio emission of RQQs appears to originate from non-thermal synchrotron radiation due to a combination of active galactic nuclei and star formation activities. However, our data suggest that the VLBI-detected radio emission from these RQQs is primarily associated with compact jets or corona, with extended emissions such as star formation and large-scale jets being resolved by the high resolution of the VLBI images. Wind emission models are not in complete agreement the VLBI observations. Unlike RLQs, where the parsec-scale radio emission is dominated by a relativistically boosted core, the radio cores of RQQs are either not dominant or are mixed with significant jet emission. RQQs with compact cores or core-jet structures typically have more pronounced variability, with flat or inverted spectra, whereas jet-dominated RQQs have steep spectra and unremarkable variability. Future high-resolution observations of more RQQs could help to determine the fraction of different emission sources and their associated physical mechanisms.

10.Constraining the geometry of the reflection nebula NGC 2023 with [O I]: Emission & Absorption

Authors:Bhaswati Mookerjea TIFR, Mumbai, India, Goeran Sandell IofA, Univ of Hawaii, Rolf Guesten MPIfR, Bonn, Helmut Wiesemeyer MPIfR, Bonn, Yoko Okada Uni of Cologne, Karl Jacobs Uni of Cologne

Abstract: We have mapped the NGC 2023 reflection nebula in the 63 and 145 micron transitions of [O I] and the 158 micron [C II] spectral lines using the heterodyne receiver upGREAT on SOFIA. The observations were used to identify the diffuse and dense components of the PDR traced by the [C II] and [O I] emission, respectively. The velocity-resolved observations reveal the presence of a significant column of low-excitation atomic oxygen, seen in absorption in the [O I] 63 micron spectra, amounting to about 20-60% of the oxygen column seen in emission in the [O I] 145 micron spectra. Some self-absorption is also seen in [C II], but for the most part it is hardly noticeable. The [C II] and [O I] 63 micron spectra show strong red- and blue-shifted wings due to photo evaporation flows especially in the southeastern and southern part of the reflection nebula, where comparison with the mid- and high-J CO emission indicates that the C+ region is expanding into a dense molecular cloud. Using a two-slab toy model the large-scale self-absorption seen in [O I] 63 micron is readily explained as originating in foreground low-excitation gas associated with the source. Similar columns have also been observed recently in other Galactic photon-dominated-regions (PDRs). These results have two implications: for the velocity-unresolved extra-galactic observations this could impact the use of [O I] 63 micron as a tracer of massive star formation and secondly the widespread self-absorption in [O I] 63 micron leads to underestimate of the column density of atomic oxygen derived from this tracer and necessitates the use of alternative indirect methods.

11.Unravelling multi-temperature dust populations in the dwarf galaxy Holmberg II

Authors:Olag Pratim Bordoloi Tezpur University, Napaam, Assam, India, Yuri A. Shchekinov Raman Research Institute, Bengaluru, India, P. Shalima Manipal Centre for Natural Sciences, Centre of Excellence, Manipal Academy of Higher Education, Manipal, Karnataka, India, M. Safonova Indian Institute of Astrophysics, Bengaluru, India, Rupjyoti Gogoi Tezpur University, Napaam, Assam, India

Abstract: Holmberg II - a dwarf galaxy in the nearby M81 group - is a very informative source of distribution of gas and dust in the interstellar discs. High-resolution observations in the infrared (IR) allows us to distinguish isolated star-forming regions, photodissociation (PDR) and HII regions, remnants of supernovae (SNe) explosions and, as such, can provide information about more relevant physical processes. In this paper we analyse dust emission in the wavelength range 4.5 to 160 micron using the data from IR space observatories at 27 different locations across the galaxy. We observe that the derived spectra can be represented by multiple dust populations with different temperatures, which are found to be independent of their locations in the galaxy. By comparing the dust temperatures with the far ultraviolet (FUV) intensities observed by the UVIT instrument onboard AstroSat, we find that for locations showing a 100 micron peak, the temperature of cold (20 to 30 K) dust grains show a dependence on the FUV intensities, while such dependence is not observed for the other locations. We believe that the approach described here can be a good tool in revealing different dust populations in other nearby galaxies with available high spatial resolution data.

12.MIDIS: JWST/MIRI reveals the Stellar Structure of ALMA-selected Galaxies in the Hubble-UDF at Cosmic Noon

Authors:Leindert A. Boogaard, Steven Gillman, Jens Melinder, Fabian Walter, Luis Colina, Göran Östlin, Karina I. Caputi, Edoardo Iani, Pablo Pérez-González, Paul van der Werf, Thomas R. Greve, Gillian Wright, Almudena Alonso-Herrero, Javier Álvarez-Márquez, Marianna Annunziatella, Arjan Bik, Sarah Bosman, Luca Costantin, Alejandro Crespo Gómez, Dan Dicken, Andreas Eckart, Jens Hjorth, Iris Jermann, Alvaro Labiano, Danial Langeroodi, Romain A. Meyer, Florian Peißker, John P. Pye, Pierluigi Rinaldi, Tuomo V. Tikkanen, Martin Topinka, Thomas Henning

Abstract: We present deep James Webb Space Telescope (JWST)/MIRI F560W observations of a flux-limited, ALMA-selected sample of 28 galaxies at z=0.5-3.6 in the Hubble Ultra Deep Field (HUDF). The data from the MIRI Deep Imaging Survey (MIDIS) reveal the stellar structure of the HUDF galaxies at rest-wavelengths of >1 micron for the first time. We revise the stellar mass estimates using new JWST photometry and find good agreement with pre-JWST analysis; the few discrepancies can be explained by blending issues in the earlier lower-resolution Spitzer data. At z~2.5, the resolved rest-frame near-infrared (1.6 micron) structure of the galaxies is significantly more smooth and centrally concentrated than seen by HST at rest-frame 450 nm (F160W), with effective radii of Re(F560W)=1-5 kpc and S\'ersic indices mostly close to an exponential (disk-like) profile (n~1), up to n~5 (excluding AGN). We find an average size ratio of Re(F560W)/Re(F160W)~0.7 that decreases with stellar mass. The stellar structure of the ALMA-selected galaxies is indistinguishable from a HUDF reference sample of galaxies with comparable MIRI flux density. We supplement our analysis with custom-made, position-dependent, empirical PSF models for the F560W observations. The results imply that an older and smoother stellar structure is in place in massive gas-rich, star-forming galaxies at Cosmic Noon, despite a more clumpy rest-frame optical appearance, placing additional constraints on galaxy formation simulations. As a next step, matched-resolution, resolved ALMA observations will be crucial to further link the mass- and light-weighted galaxy structures to the dusty interstellar medium.

1.Metal Enrichment due to Embedded Stars in AGN Discs

Authors:Jiamu Huang, Douglas N. C. Lin, Gregory Shields

Abstract: We separately assess elemental abundances in AGNs' broad and narrow emission line regions (BLR and NLR), based on a critical assessment of published results together with new photoionization models. We find 1) He/H enhancements in some AGN, exceeding what can be explained by normal chemical evolution and confirm 2) super-solar {\alpha} abundance, though to a lesser degree than previously reported. We also reaffirm 3) a N/O ratio consistent with secondary production; 4) solar or slightly sub-solar Fe abundance; and 5) red-shift independent metallicity, in contrast with galactic chemical evolution. We interpret 6) the larger metallicity in the BLR than NRL in terms of an in situ stellar evolution and pollution in AGN discs (SEPAD) model. We attribute: a) the redshift independence to the heavy element pollutants being disposed into the disc and accreted onto the central supermassive black hole (SMBH); b) the limited He excess to the accretion-wind metabolism of a top-heavy population of evolving massive main sequence stars; c) the super-solar CNO enrichment to the nuclear synthesis during their post-main-sequence evolution; d) the large N/O to the byproduct of multiple stellar generations; and e) the Mg, Si, and Fe to the ejecta of type II supernovae in the disc. These results provide supporting evidence for f) ongoing self-regulated star formation, g) adequate stellar luminosity to maintain marginal gravitational stability, h) prolific production of seeds and i) dense coexistence of subsequently-grown residual black hole populations in AGN discs.

2.On the galaxy counterpart and environment of the dusty Damped Lyman-$α$ Absorber at $z=2.226$ towards Q1218+0832

Authors:J. P. U. Fynbo, L. B. Christensen, S. J. Geier, K. E. Heintz, J. -K. Krogager, C. Ledoux, B. Milvang-Jensen, P. Møeller, S. Vejlgaard, J. Viuho, G. Östlin

Abstract: We report on further observations of the field of the quasar Q1218+0832. Geier et al. (2019) presented the discovery of the quasar resulting from a search for quasars reddened and dimmed by dust in foreground Damped Lyman-alpha Absorbers (DLAs). The DLA is remarkable by having a very large HI column density close to 10^22 cm^-2. Its dust extinction curve shows the 2175 AA-bump known from the Local Group. It also shows absorption from cold gas exemplified by CI and CO-molecules. We here present narrow-band observations of the field of Q1218+0832 and also use archival HST image to search for the galaxy counterpart of the DLA. No emission from the DLA galaxy is found neither in the narrow-band imaging nor in the HST image. In the HST image, we can probe down to an impact parameter of 0.3 arcsec and a 3-sigma detection limit of 26.8 mag per arcsec^2. In the narrow-band image, we probe down to 0 arcsec impact parameter and detect nothing down to a 3-sigma detection limit of about 3*10^-17 erg s^-1 cm^-2. We do detect a bright Lyman-alpha emitter 59 arcsec south of Q1218+0832 with a flux of 3*10^-16 erg s^-1 cm^-2. We conclude that the DLA galaxy must be located at very small impact parameter (<0.3 arcsec, 2.5 kpc) or is optically dark. Also, the DLA galaxy most likely is part of a galaxy group.

3.On the source counts of VLBI-detected radio sources and the prospects of all-sky surveys with current and next generation instruments

Authors:S. Rezaei, J. P. McKean, A. T. Deller, J. F. Radcliffe

Abstract: We present an analysis of the detection fraction and the number counts of radio sources imaged with Very Long Baseline Interferometry (VLBI) at 1.4 GHz as part of the mJIVE-20 survey. From a sample of 24,903 radio sources identified by FIRST, 4,965 are detected on VLBI-scales, giving an overall detection fraction of $19.9\pm2.9~$per cent. However, we find that the detection fraction falls from around 50 per cent at a peak surface brightness of $80~mJy~beam^{-1}$ in FIRST to around 8 per cent at the detection limit, which is likely dominated by the surface brightness sensitivity of the VLBI observations, with some contribution from a change in the radio source population. We also find that compactness at arcsec-scales is the dominant factor in determining whether a radio source is detected with VLBI, and that the median size of the VLBI-detected radio sources is 7.7 mas. After correcting for the survey completeness and effective sky area, we determine the slope of the differential number counts of VLBI-detected radio sources with flux densities $S_{\rm 1.4~GHz} > 1~mJy$ to be $\eta_{\rm VLBI} = -1.74\pm 0.02$, which is shallower than in the cases of the FIRST parent population ($\eta_{\rm FIRST} = -1.77\pm 0.02$) and for compact radio sources selected at higher frequencies ($\eta_{\rm JBF} = -2.06\pm 0.02$). From this, we find that all-sky ($3\pi~sr$) surveys with the EVN and the VLBA have the potential to detect $(7.2\pm0.9)\times10^{5}$ radio sources at mas-resolution, and that the density of compact radio sources is sufficient (5.3~deg$^{-2}$) for in-beam phase referencing with multiple sources (3.9 per primary beam) in the case of a hypothetical SKA-VLBI array.

4.The destiny of Dark Matter

Authors:Fabiano Tracanna, Steen H. Hansen

Abstract: The majority of baryons, which account for $15\%$ of the matter in the Universe, will end their lives as carbon and oxygen inside cold black dwarfs. Dark matter (DM) makes up the remaining $85\%$ of the matter in the universe, however, the fate of DM is unknown. Here we show that the destiny of purely gravitationally interacting DM particles follows one of two possible routes. The first possible route, the "radiation-destiny" scenario, is that massive DM particles lose sufficient energy through gravitational radiation causing them to spiral into a supermassive black hole that ultimately disappears through Hawking radiation. The second possible route, the "drifting-alone" destiny, applies to lighter DM particles, where only the central DM halo region spirals into the central BH which is then Hawking radiated away. The rest of the DM halo is ripped apart by the accelerated expansion of the Universe.

5.How widespread are aromatic cycles in cold clouds?

Authors:M. Agundez, N. Marcelino, B. Tercero, J. Cernicharo

Abstract: We report the detection of large hydrocarbon cycles toward several cold dense clouds. We observed four sources (L1495B, Lupus-1A, L483, and L1527) in the Q band (31-50 GHz) using the Yebes 40m radiotelescope. Using the line stack technique, we find statistically significant evidence of benzonitrile (C6H5CN) in L1495B, Lupus-1A, and L483 at the 31.8 sigma, 15.0 sigma, and 17.2 sigma levels, respectively, while there is no hint of C6H5CN in the fourth source, L1527. The column densities derived are in the range (1.8-4.0)e12 cm-2, which is somewhat below the value derived toward the cold dense cloud TMC-1. When we analyse together all the benzonitrile abundances derived toward cold clouds in this study and in the literature, a clear trend emerges in which the higher the abundance of HC7N, the more abundant C6H5CN is. This indicates that aromatic cycles are specially favored in those interstellar clouds where long carbon chains are abundant, which suggests that the chemical processes that are responsible for the formation of linear carbon chains are also behind the synthesis of aromatic rings. We also searched for cycles other than benzonitrile, and found evidence of indene (C9H8), cyclopentadiene (C5H6), and 1-cyano cyclopentadiene (1-C5H5CN) at the 9.3 sigma, 7.5 sigma, and 8.4 sigma, respectively, toward L1495B, which shows the strongest signal from C6H5CN. The relative abundances between the various cycles detected in L1495B are consistent, within a factor of three, to those found previously in TMC-1. It is therefore likely that not only C6H5CN but also other large aromatic cycles are abundant in clouds rich in carbon chains.

6.Circumgalactic Ly$α$ emission around submillimeter-bright galaxies with different quasar contributions

Authors:Vale González Lobos, Fabrizio Arrigoni Battaia, Seok-Jun Chang, Max Gronke, Guinevere Kauffmann, Chian-Chou Chen, Hai Fu, Aura Obreja, Emanuele P. Farina

Abstract: We present VLT/MUSE observations targeting the extended Lyman-$\alpha$ (Ly$\alpha$) emission of five high-redshift ($z\sim$3-4) submillimeter galaxies (SMGs) with increasing quasar (QSO) radiation: two SMGs, two SMGs hosting a QSO, and one SMG hosting a QSO with a SMG companion (QSO+SMG). These sources should be located in dark matter halos of comparable masses (average mass of $M_{\rm DM}\sim10^{12.2}\,{\rm M}_\odot$). We quantify the luminosity and extent of the Ly$\alpha$ emission, together with its kinematics, and examine four Ly$\alpha$ powering mechanisms: photoionization from QSOs/star formation, shocks by galactic/QSO outflows, gravitational cooling radiation, and Ly$\alpha$ photons resonant scattering. We find a variety of Ly$\alpha$ luminosities and extents, with the QSO+SMG system displaying the most extended and bright nebula, followed by the SMGs hosting a QSO, and finally the undetected circumgalactic medium (CGM) of SMGs. This diversity implies that gravitational cooling is unlikely to be the main powering mechanism. We show that photoionization from the QSO and QSO outflows can contribute to power the emission for average densities $n_{\rm H}>0.5\,$cm$^{-3}$. Moreover, the observed Ly$\alpha$ luminosities scale with the QSO's budget of Ly$\alpha$ photons modulo the dust content in each galaxy, highlighting a possible contribution from resonant scattering of QSO's radiation in powering the nebulae. We find larger Ly$\alpha$ linewidths (FWHM$\gtrsim 1200\,$km$\,$s$^{-1}$) than usually reported around radio-quiet systems, pointing to large-scale outflows. A statistical survey targeting similar high-redshift massive systems with known host properties is needed to confirm our findings.

7.On the dominant role of wind in the quasar feedback mode in the late stage evolution of massive elliptical galaxies

Authors:Bocheng Zhu, Feng Yuan, Suoqing Ji, Yingjie Peng, Luis C. Ho

Abstract: In this paper we investigate the role of AGN feedback on the late stage evolution of elliptical galaxies by performing high-resolution hydrodynamical simulation in the {\it MACER} framework. By comparing models that take into account different feedback mechanisms, namely AGN and stellar feedback, we find that AGN feedback is crucial in keeping the black hole in a low accretion state and suppressing the star formation. We then compare the energy from AGN radiation and wind deposited in the galaxy and find that only wind can compensate for the radiative cooling of the gas in the galaxy. Further, we investigate which plays the dominant role, the wind from the cold (quasar) or hot (radio) feedback modes, by examining the cumulative energy output and impact area to which the wind can heat the interstellar medium and suppress star formation. Our results indicate that first, although AGN spends most of its time in hot (radio) mode, the cumulative energy output is dominated by the outburst of the cold mode. Second, only the impact area of the cold-mode wind is large enough to heat the gas in the halo, while the hot-mode wind is not. Additionally, the cold-mode wind is capable of sweeping up the material from stellar mass loss. These results indicate the dominant role of cold-mode wind. The limitations of our model, including the absence of jet feedback, are discussed.

8.The dawn is quiet here: Rise in [$α$/Fe] is a signature of massive gas accretion that fueled proto-Milky Way

Authors:Boquan Chen, Yuan-Sen Ting, Michael Hayden

Abstract: The proto-Milky Way epoch forms the earliest stars in our Galaxy and sets the initial conditions for subsequent disk formation. Recent observations from APOGEE and H3 surveys showed that the [$\alpha$/Fe] ratio slowly declined between [Fe/H] $=-3$ and $-1.3$ until it reached the lowest value ($\sim 0.25$) among the selected in situ metal-poor stars that most likely formed during the proto-Galaxy epoch. [$\alpha$/Fe] rose to meet the traditional high value commonly associated with the thick disk population at [Fe/H] $=-1$. It was suggested that the rise in [$\alpha$/Fe] could be caused by an increase in the star formation efficiency (SFE), known as the "simmering" phase scenario. However, gas inflow also plays a vital role in shaping the star formation history and chemical evolution of galaxies. We investigate this unexpected [$\alpha$/Fe]-rise with a statistical experiment involving a galactic chemical evolution (GCE). Our model has five free parameters: the mass of the initial reservoir of the cold interstellar medium (ISM) at birth, the frequency of Type Ia supernovae (SNe Ia), the cooling timescale of the warm ISM, the SFE, and the inflow rate of fresh gas. The last two free parameters were allowed to change after [$\alpha$/Fe] reached its lowest value, dividing the proto-Galaxy epoch into two phases. We find that the rise in [$\alpha$/Fe] is caused by a large inflow of fresh gas and conclude that the [$\alpha$/Fe]-rise is a signature of the cold mode accretion whose materials formed the prototype Milky Way preceding disk formation. Although the SFE is essential in regulating the chemical evolution, it does not necessarily increase to facilitate the [$\alpha$/Fe]-rise.

9.JWST reveals widespread CO ice and gas absorption in the Galactic Center cloud G0.253+0.015

Authors:Adam Ginsburg, Ashley T. Barnes, Cara D. Battersby, Alyssa Bulatek, Savannah Gramze, Jonathan D. Henshaw, Desmond Jeff, Xing Lu, E. A. C. Mills, Daniel L. Walker

Abstract: We report JWST NIRCam observations of G0.253+0.015, the molecular cloud in the Central Molecular Zone known as The Brick, with the F182M, F187N, F212N, F410M, F405N, and F466N filters. We catalog 56,146 stars detected in all 6 filters using the crowdsource package. Stars within and behind The Brick exhibit prodigious absorption in the F466N filter that is produced by a combination of CO ice and gas. In support of this conclusion, and as a general resource, we present models of CO gas and ice and CO$_2$ ice in the F466N, F470N, and F410M filters. Both CO gas and ice may contribute to the observed stellar colors. We show, however, that CO gas does not absorb the Pf$\beta$ and Hu$\epsilon$ lines in F466N, but that these lines show excess absorption, indicating that CO ice is also present and contributes to observed F466N absorption. The most strongly absorbed stars in F466N are extincted by $\sim$ 2 magnitudes, corresponding to $>$ 80\% flux loss. This high observed absorption requires very high column densities of CO, requiring total CO column that is in tension with standard CO abundance and/or gas-to-dust ratios. There is therefore likely to be a greater CO/H$_2$ ratio (X$_{CO} > 10^{-4}$) and more dust per H$_2$ molecule ($>0.01$) in the Galactic Center than the Galactic disk. Ice and/or gas absorption is observed even in the cloud outskirts, implying that additional caution is needed when interpreting stellar photometry in filters that overlap with ice bands throughout our Galactic Center. The widespread CO absorption in our Galactic Center hints that significant ice absorption is likely present in other galactic centers.

10.A FUV and optical study of star formation in closely interacting galaxies: star forming rings, tidal arms and nuclear outflows

Authors:Jyoti Yadav IIA, Mousumi Das IIA, Sudhanshu Barway IIA, Francoise Combes Obs-Paris, LERMA

Abstract: We present a study of the morphology of star formation and the associated nuclear activity in a sample of 8 closely interacting southern galaxies, which are in different stages of interaction, starting with nearly merged nuclei that have one prominent bulge to more widely spaced interacting galaxies. We have used Far-Ultraviolet (FUV) observations from the Ultraviolet Imaging telescope (UVIT), near-Infrared observations from the infrared survey facility telescope (IRSF) and archival optical data from the VLT/MUSE integral field spectrograph. Analysing resolved stellar populations across the disk of the interacting galaxies can provide unique insights into how interactions affect galaxy properties, such as morphology, star formation rates and chemical composition. We take advantage of the unprecedented capabilities of MUSE and UVIT to carry out a highly detailed spatially and spectrally resolved study of star formation rate, star formation histories, metallicity and AGN activity in the sample of eight interacting galaxies which are in different stages of interaction. Most of our sample galaxies are gas-rich and show evidence of recent, massive star formation in tidal tails, rings and spiral arms. This is evident from their FUV and H$\alpha$ emissions, which trace young, massive star-forming regions. We compared the star formation rate in the barred and unbarred galaxies in our sample and found that the barred galaxies do not show significant enhancement in star formation rate or large-scale difference in star formation morphology compared to unbarred galaxies. IC5250 and NGC7733N, show extended nuclear outflows of size $\sim$ 5 kpc and 8 kpc respectively.

1.Dynamical Influence of a Central Massive Object on Double-Barred Galaxies: Self-Destruction Mechanism of Secondary Bars

Authors:Naoki Nakatsuno Kagoshima University, Junichi Baba Kagoshima University

Abstract: Double-barred galaxies exhibit sub-kpc secondary stellar bars that are crucial for channeling gases towards a central massive object (CMO) such as a supermassive black hole or a nuclear star cluster. Recent $N$-body simulations have uncovered a novel galaxy evolution scenario wherein the mass of the CMO increases owing to the secondary bar, resulting in the eventual destruction of the latter. Consequently, the CMO mass growth halts, thus suggesting a maximum CMO mass of $\approx 10^{-3}$ of the stellar mass of the galaxy. This study focused on backbone orbit families, particularly double-frequency orbits, within double-barred galaxies. Consequently, the dynamic influence of a CMO on these orbits was investigated. The results of the study revealed the emergence of a new orbital resonance within the central region of the galaxy upon the introduction of a CMO. Orbits subjected to this resonance become chaotic and fail to support the secondary bar, ultimately resulting in the destruction of the entire structure. This is partly because of the inability of the secondary bar to obtain support from the newly generated orbit families following the appearance of resonance. Through the estimation of the condition of secondary bar destruction in realistic double-bar galaxies with varying pattern speeds, the results of the study established that such destruction occurred when the CMO mass reached $\approx 10^{-3}$ of the galaxy mass. Furthermore, a physical explanation of the galaxy evolution scenario was provided, thereby elucidating the interaction between the CMO and the secondary bar. The understanding of the co-evolution of the secondary bar and the CMO, based on stellar orbital motion, is a crucial step towards future observational studies of stars within the bulge of the Milky Way.

2.Theoretical Analysis of Random Scattering Induced by Microlensing

Authors:Wenwen Zheng, Hou-Zun Chen, Xuechun Chen, Guoliang Li

Abstract: Theoretical investigations into the deflection angle caused by microlenses offer a direct path to uncovering principles of the cosmological microlensing effect. This work specifically concentrates on the the probability density function (PDF) of the light deflection angle induced by microlenses. We have made several significant improvements to the widely used formula from Katz et al. First, we update the coefficient from 3.05 to 1.454, resulting in a better fit between the theoretical PDF and our simulation results. Second, we developed an elegant fitting formula for the PDF that can replace its integral representation within a certain accuracy, which is numerically divergent unless arbitrary upper limits are chosen. Third, to facilitate further theoretical work in this area, we have identified a more suitable Gaussian approximation for the fitting formula.

3.Evidence for a large off-centered galactic outflow and its connection to the extraplanar diffuse ionized gas in IC 1553

Authors:Lukas Dirks, Ralf-Jürgen Dettmar, Dominik J. Bomans, Peter Kamphuis, Ulrich Schilling

Abstract: Aims. We analyze a MUSE optical integral field spectrum of the star-forming edge-on galaxy IC 1553 in order to study its extraplanar diffuse ionized gas (eDIG) and the processes shaping its disk-halo interface. Methods. We extracted the optical emission line properties from the integral field spectrum and generated the commonly used emission line diagnostic diagrams in order to analyze the ionization conditions and the distribution of the eDIG. Furthermore, we performed gravitational potential fitting to investigate the kinematics of a suspected galactic outflow. Results. We find that the eDIG scale height has a maximum value of approximately 1.0 kpc and decreases roughly linearly with the radial distance from the galactic center in projection. The ionization state of the eDIG is not consistent with a pure photoionization scenario and instead requires a significant contribution from shock ionization. This, in addition to the gas kinematics, strongly suggests the presence of a galactic scale outflow, the origin of which lies at least 1.4 kpc away from the galactic center. The inferred shock velocity in the eDIG of approximately 225 km s-1 is comparable to the escape velocity estimated from our potential modelling. The asymmetric distribution of currently star-forming clusters produces a range of different ionization conditions in the eDIG. As a result, the vertical emission line profiles vary quantitatively and qualitatively along the major axis of the galaxy. This analysis illustrates that it is crucial in studies of the eDIG to use observations that take the spatial and kinematical distributions into account, such as those done with integral field units, to form an accurate picture of the relevant physical properties.

4.Multiple imaging of the quasar 2005+403 formed by anisotropic scattering

Authors:T. A. Koryukova ASC LPI, A. B. Pushkarev CrAO, ASC LPI, S. Kiehlmann FORTH, UoC, A. C. S. Readhead Caltech

Abstract: We report on the low Galactic latitude ($b=4.3^\circ$) quasar 2005$+$403, the second active galactic nuclei, in which we detected a rare phenomenon of multiple imaging induced by refractive-dominated scattering. The manifestation of this propagation effect is revealed at different frequencies ($\lesssim8$ GHz) and epochs of VLBA observations. The pattern formed by anisotropic scattering is stretched out along the line of constant Galactic latitude with a local $\mathrm{PA}\approx40^\circ$ showing one-two sub-images, often on either side of the core. Analysing the multi-frequency VLBA data ranging from 1.4 to 43.2 GHz, we found that both the angular size of the apparent core component and the separation between the primary and secondary core images follow a $\lambda^2$ dependence, providing convincing evidence for a plasma scattering origin for the multiple imaging. Based on the OVRO long-term monitoring data at 15 GHz obtained for 2005$+$403, we identified the characteristic flux density excursions occurred in April-May 2019 and attributed to an extreme scattering event (ESE) associated with the passage of a plasma lens across the line of sight. Modeling the ESE, we determined that the angular size of the screen is 0.4 mas and it drifts with the proper motion of 4.4 mas yr$^{-1}$. Assuming that the scattering screen is located in the highly turbulent Cygnus region, the transverse linear size and speed of the lens with respect to the observer are 0.7 AU and 37 km s$^{-1}$, respectively.

5.Are there any extragalactic high speed dark matter particles in the Solar neighborhood?

Authors:Isabel Santos-Santos, Nassim Bozorgnia, Azadeh Fattahi, Julio F. Navarro

Abstract: We use the APOSTLE suite of cosmological hydrodynamical simulations of the Local Group to examine the high speed tail of the local dark matter velocity distribution in simulated Milky Way analogues. The velocity distribution in the Solar neighborhood is well approximated by a generalized Maxwellian distribution sharply truncated at a well-defined maximum ``escape" speed. The truncated generalized Maxwellian distribution accurately models the local dark matter velocity distribution of all our Milky Way analogues, with no evidence for any separate extragalactic high-speed components. The local maximum speed is well approximated by the terminal velocity expected for particles able to reach the Solar neighborhood in a Hubble time from the farthest confines of the Local Group. This timing constraint means that the local dark matter velocity distribution is unlikely to contain any high-speed particles contributed by the Virgo Supercluster ``envelope", as argued in recent works. Particles in the Solar neighborhood with speeds close to the local maximum speed can reach well outside the virial radius of the Galaxy, and, in that sense, belong to the Local Group envelope posited in earlier work. The local manifestation of such envelope is thus not a distinct high-speed component, but rather simply the high-speed tail of the truncated Maxwellian distribution.

1.White Dwarf--White Dwarf collisions in AGN discs via close encounters

Authors:Yan Luo USTC, Xiao-Jun Wu USTC, Shu-Rui Zhang USTC, Jian-Min Wang IHEP, Luis C. Ho PKU, Ye-Fei Yuan USTC

Abstract: White dwarfs (WDs) in active galactic nucleus (AGNs) discs might migrate to the inner radii of the discs and form restricted three-body systems with two WDs moving around the central supermassive black hole (SMBH) in close orbits. These systems could be dynamical unstable, which can lead to very close encounters or direct collisions. In this work, we use N-body simulations to study the evolution of such systems with the different initial orbital separation $p$, relative orbital inclination $\Delta{i}$ and SMBH mass $M$. It is found that the close encounters of WDs mainly occur at $1.1R_{\rm H} \lesssim p \lesssim 2\sqrt{3}R_{\rm H}$, where $R_{\rm H}$ is the mutual Hill radius. For $p<1.1R_{\rm H}$, the majority of WDs move in horseshoe or tadpole orbits, and only few of them with small initial orbital phase difference undergo close encounters. For $p=3.0R_{\rm H}$, WD-WD collisions occur in most of the samples within a time of $10^5P_1$, and considerable collisions occur within a time of $t<62P_1$ for small orbital radii, where $P_1$ is the orbital period. The peak of the closest separation distribution increase and the WD-WD collision fraction decreases with an increase of the relative inclination. The closest separation distribution is similar in cases with the different SMBH mass, but the WD-WD collision fraction decreases as the mass of SMBHs increases. According to our estimation, the event rate of the cosmic WD-WD collision in AGN discs is about $300{\rm Gpc^{-3}yr^{-1}}$, roughly $1\%$ of the one of the observed type Ia supernova. The corresponding electromagnetic emission signals can be observed by large surveys of AGNs.

2.Identification of the simplest sugar-like molecule glycolaldehyde towards the hot molecular core G358.93-0.03 MM1

Authors:Arijit Manna, Sabyasachi Pal, Serena Viti, Sekhar Sinha

Abstract: Glycolaldehyde (CH$_{2}$OHCHO) is the simplest monosaccharide sugar in the interstellar medium, and it is directly involved in the origin of life via the 'RNA world' hypothesis. We present the first detection of glycolaldehyde (CH$_{2}$OHCHO) towards the hot molecular core G358.93-0.03 MM1 using the Atacama Large Millimeter/Submillimeter Array (ALMA). The calculated column density of CH$_{2}$OHCHO towards G358.93-0.03 MM1 is (1.52$\pm$0.9)$\times$10$^{16}$ cm$^{-2}$ with an excitation temperature of 300$\pm$68.5 K. The derived fractional abundance of CH$_{2}$OHCHO with respect to H$_{2}$ is (4.90$\pm$2.92)$\times$10$^{-9}$, which is consistent with that estimated by existing two-phase warm-up chemical models. We discuss the possible formation pathways of CH$_{2}$OHCHO within the context of hot molecular cores and hot corinos and find that CH$_{2}$OHCHO is likely formed via the reactions of radical HCO and radical CH$_{2}$OH on the grain surface of G358.93-0.03 MM1.

3.Inferring the presence of very massive stars in local star-forming regions

Authors:Fabrice Martins LUPM, CNRS & Montpellier University, Daniel Schaerer Geneva University IRAP, CNRS, Rui Marques-Chaves Geneva University, Ankur Upadhyaya Geneva University

Abstract: We present a study aiming at detecting VMS in local star-forming region from the imprint they leave on the integrated UV and optical light. We analyzed a sample of 27 star-forming regions and galaxies in the local Universe. We selected sources with a metallicity close to that of the LMC. We defined empirical criteria to distinguish sources dominated by VMS and Wolf-Rayet stars (WR), using template spectra of VMS- and WR-dominated regions. We subsequently built population synthesis models with an updated treatment of VMS. We show that the UV range alone is not sufficient to distinguish between VMS- and WR-dominated sources. The region of the WR bumps in the optical breaks the degeneracy. In particular, the morphology of the blue bump at 4640-4686 A is a key diagnostic. Beyond the prototypical R136 region we identify two galaxies showing clear signatures of VMS. In two other galaxies or regions the presence of VMS can be suspected, as already discussed in the literature. The stellar population is clearly dominated by WR stars in seven other sources. The most recent BPASS population synthesis models can neither account for the strong HeII 1640 emission, nor for the shape of the blue bump in VMS- and WR-dominated sources. Our models that include VMS more realistically reproduce the UV-optical spectra of VMS-dominated sources. We conclude that VMS are present in some local star-forming regions, but that separating them from WR-dominated populations requires optical spectroscopy with a high signal-to-noise ratio. A high equivalent width of HeII 1640 is not a sufficient condition for identifying VMS. Populations synthesis models need to take VMS into account by incorporating not only evolutionary tracks, but also dedicated spectral libraries. Finally, we stress that the treatment of WR stars needs to be improved as well.

4.Explaining the oblate morphology of dwarf spheroidals with Wave Dark Matter perturbations

Authors:Riccardo Della Monica, Ivan de Martino, Tom Broadhurst

Abstract: We investigate whether the oblate, spheroidal morphology of common dwarf spheroidal galaxies (dSph) may result from the slow relaxation of stellar orbits within a halo of Wave Dark Matter ($\psi$DM) when starting from an initial disk of stars. Stellar orbits randomly walk over a Hubble time, perturbed by the pervasive "granular" interference pattern of $\psi$DM, that fully modulates the dark matter density on the de Broglie scale. Our simulations quantify the level of stellar disk thickening over the Hubble time, showing that distribution of stars is predicted to become an oblate spheroid of increasing radius, that plausibly accounts for the morphology of dSph galaxies. We predict a low level of residual rotation remains after a Hubble time at the 1-3 km/s level, depending on orientation, that compares with recent claims of rotation for some well studied local dSph galaxies. This steady internal dynamical evolution may be witnessed directly with JWST for well resolved dwarf galaxies, appearing more oblate with look back time and tending to small disks of young stars at high redshift.

5.Scalar Field Dark Matter: Impact of Supernovae-driven blowouts on the soliton structure of low mass dark matter halos

Authors:Victor H. Robles, J. L. Zagorac, N. Padmanabhan

Abstract: We present the first study on the gravitational impact of supernova feedback in an isolated soliton and a spherically symmetric dwarf SFDM halo of virial mass $1\times 10^{10}\mathrm{M_\odot}$. We use a boson mass $m=10^{-22}\mathrm{eV/c^2}$ and a soliton core $r_c \approx 0.7$kpc, comparable to typical half-light radii of Local Group dwarf galaxies. We simulate the rapid gas removal from the center of the soliton by a concentric external time-dependent Hernquist potential. We explore two scenarios of feedback blowouts: i) a massive single burst, and ii) multiple consecutive blowouts injecting the same total energy to the system, including various magnitudes for the blowouts in both scenarios. In all cases, we find one single blowout has a stronger effect on reducing the soliton central density. Feedback leads to central soliton densities that oscillate quasi-periodically for an isolated soliton and stochastically for a SFDM halo. The range in the density amplitude depends on the strength of the blowout, however we observe typical variations of a factor of $\geqslant$2. One important consequence of the stochastic fluctuating densities is that, if we had no prior knowledge of the system evolution, we can only know the configuration profile at a specific time within some accuracy. By fitting soliton profiles at different times to our simulated structures, we found the (1-$\sigma$) scatter of their time-dependent density profiles. For configurations within the 1$\sigma$ range, we find the inferred boson mass is typically less than 20\% different from the real value used in our simulations. Finally, we compare the observed dynamical masses of field dwarf galaxies in our Local Group with the implied range of viable solitons from our simulations and find good agreement.

6.The puzzling properties of the MACS1149-JD1 galaxy at z=9.11

Authors:Massimo Stiavelli, Takahiro Morishita, Marco Chiaberge, Claudio Grillo, Piero Rosati, Stefan Schuldt, Michele Trenti, Tommaso Treu

Abstract: We analyze new JWST NIRCam and NIRSpec data on the redshift 9.11 galaxy MACS1149-JD1. Our NIRCam imaging data reveal that JD1 comprises three spatially distinct components. Our spectroscopic data indicate that JD1 appears dust-free but is already enriched, $12 + \log {\rm (O/H) } = 7.875^{+0.042}_{-0.045}$. We also find that the Carbon and Neon abundances in JD1 are below the solar abundance ratio. Particularly the Carbon under-abundance is suggestive of recent star formation where Type~II supernovae have already enriched the ISM in Oxygen but intermediate mass stars have not yet enriched the ISM in Carbon. A recent burst of star formation is also revealed by the star formation history derived from NIRCam photometry. Our data do not reveal the presence of a significant amount of old populations, resulting in a factor of $\sim7\times$ smaller stellar mass than previous estimates. Thus, our data support the view that JD1 is a young object.

1.The mid-infrared variability of the SDSS optical quasars

Authors:Hongtao Wang, Yong Shi

Abstract: Based on the Seventh Data Release (DR7) quasar catalog from the Sloan Digital Sky Survey, we investigate the variability of optical quasars in W1, W2, W3 and W4 bands of the Wide-field Infrared Survey Explorer (WISE) and the Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE). Adopting the structure function method, we calculate the structure function ($\rm\delta t$=1 yr) which shows no obvious correlations with the bolometric luminosity, the black hole mass and the Eddington ratio. The ensemble structure functions in W1 and W2 bands show that the SF slopes are steeper than those in previous studies which may be caused by different cadence and observational epoch number. We further investigate the relation of variability amplitude $\sigma_m$ between mid-infrared band and optical band, but no obvious correlation is found. No correlation is found between W1-W2 and g-r color. We think the mid-infrared emission of quasars may be smoothed out by the extended dust distribution, thus leading to no obvious correlation. For the radio-loud quasar sub-sample, we further analyze the relation between the variability amplitude in the mid-infrared band and the radio luminosity at 6 cm, but no obvious correlations are found, which indicate the mid-infrared emission contributed from the synchrotron radiation of the relativistic jet is very weak.

2.Numerical models of planetary nebulae with different episodes of mass ejection: the particular case of HuBi 1

Authors:Ary Rodríguez-González, Miriam Peña, Liliana Hernández-Martínez, Francisco Ruiz-Escobedo, Alejandro Raga, Grazyna Stasinka, Jorge Ivan Castorena

Abstract: We have studied the evolution of HuBi 1-like planetary nebulae, considering several stages of mass injection. We have carried out numerical ionization+1D hydrodynamics+atomic/ionic rate models with our code Coral 1D to reproduce planetary nebulae that present multiple shells produced by different ejection events around the ionizing source. Furthermore, we are interested in comparing numerical simulations with H$\alpha$ and [NII]$\lambda$6584 emission structures and the position-velocity diagrams observed in HuBi 1. This object also has a phase where it has drastically decreased the injection of ionized photons ejected from the source. The result of these different stages of ejection is a nebula with intense [NII] line emission in the inner part of the planetary nebula and an extended HII recombination line emission around the central zone. The model for HuBi 1 shows the capability of our code to explain the hydrodynamical and photoionization evolution in ionization nebulae. This is our first step with a 1D code to study these two physical phenomena at the same time.

3.Tracing obscured galaxy build-up at high redshift using deep radio surveys

Authors:Stergios Amarantidis, Jose Afonso, Israel Matute, Duncan Farrah, A. M. Hopkins, Hugo Messias, Ciro Pappalardo, N. Seymour

Abstract: A fundamental question of extra-galactic astronomy that is yet to be fully understood, concerns the evolution of the star formation rate (SFR) and supermassive black hole (SMBH) activity with cosmic time, as well as their interplay and how it impacts galaxy evolution. A primary focus that could shed more light on these questions is the study of merging systems, comprising highly star-forming galaxies (SFGs) and active galactic nuclei (AGN) at the earliest stages of galactic formation. However, it is essential to explore complementary selection methods across multiple wavelengths. The primary objective of this study is to conduct a comprehensive analysis of a sample of high-redshift ($z>3$) far-infrared (far-IR) and radio-emitting galaxies in the highest possible spatial resolution. In order to select the galactic population of our interest, we selected galaxies that present relatively compact radio morphologies at 1.4 GHz as well as a far-IR spectrum that peaks in flux at $\lambda \geq 350 \, \mu m$. For these selection criteria, we used the COSMOS and ECDF-S fields, which provide high spectral and spatial resolution at a multi-wavelength scale. We derived a sample of eight galaxies that were identified either photometrically or spectroscopically at $z>3$ from literature studies and by our team. A thorough investigation of available optical, near-IR, and millimetre (mm) imaging reveals a possible merging scenario in five out of eight cases in our sample. Additionally, available multi-wavelength photometry strongly suggests active star formation at the $10^3 \, M_{\odot}/yr$ level in massive systems co-hosting an active SMBH. Comparison of these results with previous studies, suggests that our selection method preferentially identifies galaxies hosting an active SMBH, as well as a strong SFG component, resulting in high SFR and IR luminosity.

4.Star Formation at the Epoch of Reionization with CANUCS: The ages of stellar populations in MACS1149-JD1

Authors:Maruša Bradač, Victoria Strait, Lamiya Mowla, Kartheik G. Iyer, Gaël Noirot, Chris Willott, Gabe Brammer, Roberto Abraham, Yoshihisa Asada, Guillaume Desprez, Vince Estrada-Carpenter, Anishya Harshan, Nicholas S. Martis, Jasleen Matharu, Adam Muzzin, Gregor Rihtaršič, Ghassan T. E. Sarrouh, Marcin Sawicki

Abstract: We present measurements of stellar populations properties of a z = 9.1 gravitationally lensed galaxy MACS1149-JD1 using deep JWST NIRISS slitless spectroscopy as well as NIRISS and NIRCam imaging from the CAnadian NIRISS Unbiased Cluster Survey (CANUCS). The galaxy is split into four components. Three magnified (${\mu}$ ~ 17) star-forming components are unresolved, giving intrinsic sizes of < 50pc. In addition, the underlying extended component contains the bulk of the stellar mass, formed the majority of its stars ~ 50Myr earlier than the other three components and is not the site of the most active star formation currently. The NIRISS and NIRCam resolved photometry does not confirm a strong Balmer break previously seen in Spitzer. The NIRISS grism spectrum has been extracted for the entire galaxy and shows a clear continuum and Lyman-break, with no Lyman-${\alpha}$ detected.

5.\HI{} 21cm observations and dynamical modelling of the thinnest galaxy: FGC 2366

Authors:K. Aditya, Arunima Banerjee, Peter Kamphuis, Aleksandr Mosenkov, Dmitry Makarov, Sviatoslav Borisov

Abstract: Superthin galaxies are bulgeless low surface brightness galaxies with unusually high major-to-minor axes ratio of the stellar disc, i.e.,$10<a/b<20$. We present Giant Metrewave Radio Telescope (GMRT) \HI{} 21cm radio-synthesis observations of FGC 2366, the thinnest galaxy known with $a/b=21.6$. Employing the 3-D tilted-ring modelling using Fully Automated TiRiFiC (FAT), we determine the structure and kinematics of the \HI{} gas disc, obtaining an asymptotic rotational velocity equal to 100 \kms and a total \HI{} mass equal to 10$^9 M_{\odot}$. Using $z$-band stellar photometry, we obtain a central surface brightness of 22.8 mag ${\rm{arcsec}}^{-2}$, a disc scale length of 2.6 kpc, and a scaleheight of 260 pc. Next, we determine the dark matter density profile by constructing a mass model and find that an NFW dark matter halo best fits the steeply-rising rotation curve. With the above mass inventory in place, we finally construct the dynamical model of the stellar disc of FGC 2366 using the stellar dynamical code "AGAMA". To identify the key physical mechanisms responsible for the superthin vertical structure, we carry out a Principal Component Analysis of the data corresponding to all the relevant dynamical parameters and $a/b$ for a sample of superthin and extremely thin galaxies studied so far. We note that the first two principal components explain 80$\%$ of the variation in the data, and the significant contribution is from the compactness of the mass distribution, which is fundamentally responsible for the existence of superthin stellar discs.

6.Objects in JWST's mirrors are closer than they appear

Authors:Stephen Serjeant, Tom J. L. C. Bakx

Abstract: The James Webb Space Telescope (JWST) has revealed extremely distant galaxies at unprecedentedly early cosmic epochs from its deep imaging using the technique of photometric redshift estimation, with its subsequent spectroscopy confirming their redshifts unambiguously, demonstrating the ability of JWST to probe the earliest galaxies, one of its major scientific goals. However, as larger samples continue to be followed up spectroscopically, it has become apparent that nearly all photometric redshifts at these epochs are biased high with confidence >>99%, for as yet unclear reasons. Here we show that this is the same statistical effect that was predicted in different contexts by Sir Arthur Eddington in 1913, in that there exist more lower redshift galaxies to be scattered upwards than the reverse. The bias depends on the shape of the intrinsic redshift distribution, but as an approximate heuristic, all ultra-high photometric redshift estimates must be corrected downwards by up to one standard deviation.

7.CECILIA: The Faint Emission Line Spectrum of z~2-3 Star-forming Galaxies

Authors:Allison L. Strom, Gwen C. Rudie, Ryan F. Trainor, Gabriel B. Brammer, Michael V. Maseda, Menelaos Raptis, Noah S. J. Rogers, Charles C. Steidel, Yuguang Chen, David R. Law

Abstract: We present the first results from CECILIA, a Cycle 1 JWST NIRSpec/MSA program that uses ultra-deep ~30 hour G235M/F170LP observations to target multiple electron temperature-sensitive auroral lines in the spectra of 33 galaxies at z~1-3. Using a subset of 23 galaxies, we construct two ~600 object-hour composite spectra, both with and without the stellar continuum, and use these to investigate the characteristic rest-optical (5700-8500 Angstrom) spectrum of star-forming galaxies at the peak epoch of cosmic star formation. Emission lines of eight different elements (H, He, N, O, Si, S, Ar, and Ni) are detected, with most of these features observed to be <3% the strength of H-alpha. We report the characteristic strength of three auroral lines ([NII]5756, [SIII]6313, and [OII]7322,7332), as well as other semi-strong and faint emission lines, including forbidden [NiII]7380,7414 and the OI 8449 recombination line, some of which have never before been observed outside of the local universe. Using these measurements, we find T_e[NII]=13630+/-2540$ K, representing the first measurement of electron temperature using [NII] in the high-redshift universe. We also see evidence for broad line emission with a FWHM of ~544 km/s; the broad component of H-alpha is 6.01-28.31% the strength of the narrow component and likely arises from star-formation driven outflows. Finally, we briefly comment on the feasibility of obtaining large samples of faint emission lines using JWST in the future.

1.AMUSE-antlia I: Nuclear X-ray properties of early-type galaxies in a dynamically young galaxy cluster

Authors:Zhensong Hu, Yuanyuan Su, Zhiyuan Li, Kelley M. Hess, Ralph P. Kraft, William R. Forman, Paul E. J. Nulsen, Sarrvesh S. Sridhar, Andra Stroe, Junhyun Baek, Aeree Chung, Dirk Grupe, Hao Chen, Jimmy A. Irwin, Christine Jones, Scott W. Randall, Elke Roediger

Abstract: To understand the formation and growth of supermassive black holes (SMBHs) and their co-evolution with host galaxies, it is essential to know the impact of environment on the activity of active galactic nuclei (AGN). We present new Chandra X-ray observations of nuclear emission from member galaxies in the Antlia cluster, the nearest non-cool core and the nearest merging galaxy cluster, residing at D = 35.2 Mpc. Its inner region, centered on two dominant galaxies NGC 3268 and NGC 3258, has been mapped with three deep Chandra ACIS-I pointings. Nuclear X-ray sources are detected in 7/84 (8.3%) early-type galaxies (ETG) and 2/8 (25%) late-type galaxies with a median detection limit of 8x10^38 erg/s. All nuclear X-ray sources but one have a corresponding radio continuum source detected by MeerKAT at the L-band. Nuclear X-ray sources detected in early-type galaxies are considered as the genuine X-ray counterpart of low-luminosity AGN. When restricted to a detection limit of logLx(erg/s) > 38.9 and a stellar mass of 10 < log Ms(Msun) <11.6, 6/11 (54.5%) ETG are found to contain an X-ray AGN in Antlia, exceeding the AGN occupation fraction of 7/39 (18.0%) and 2/12 (16.7%) in the more relaxed, cool core clusters, Virgo and Fornax, respectively, and rivaling that of the AMUSE-Field ETG of 27/49 (55.1%). Furthermore, more than half of the X-ray AGN in Antlia are hosted by its younger subcluster, centered on NGC 3258. We believe that this is because SMBH activity is enhanced in a dynamically young cluster compared to relatively relaxed clusters.

2.Milky Way globular clusters on cosmological timescales. III. Interaction rates

Authors:Maryna Ishchenko, Margaryta Sobolenko, Peter Berczik, Chingis Omarov, Olexander Sobodar, Mukhagali Kalambay, Denis Yurin

Abstract: Aims. We carry out the self-consistent dynamic evolution of the orbital structure of Milky Way globular clusters. This allows us to estimate possible and probable close passages and even collisions of the clusters with each other. Methods. We reproduced the orbits of 147 globular clusters in 10 Gyr lookback time using our own high-order N-body parallel dynamic phi-GPU code. The initial conditions (three coordinates and three velocities for the present time) were derived from the Gaia DR3 catalogue. The galaxy is represented by five external potentials from the IllustrisTNG-100, whose masses and sizes of the disk and halo components are similar to the physical values of the Milky Way at present. Results. We present a statistical analysis of the cumulative close passages rate: About ten close passages with relative distances shorter than 50 pc for every billion years for each of the five external potentials. We present the 22 most reliable collision pairs with a good probability. As an example: Terzan 4 versus Terzan 2 (49%), Terzan 4 versus NGC 6624 (44%), Terzan 4 versus Terzan 5 (40%), Terzan 4 versus NGC 6440 (40%), and Terzan 4 versus Liller 1 (42%). The most active globular cluster in the collision sense is Terzan 4, which has 5.65 collision events on average (averaged over all individual 1000 initial condition realisations). Most collisions are located inside the Galactic disk and form two ring-like structures. The first ring-like structure has the highest collision number density at 1 kpc, and the second sturcture has a maximum at 2 kpc. Conclusions. Based on our numerical simulations, we can conclude that the few dozen Milky Way globular clusters probably undergo some close encounters and even possible collisions during their lifetimes, which can significantly affect their individual dynamical evolution and possibly even their stellar content.

3.Uncovering a Massive z~7.65 Galaxy Hosting a Heavily Obscured Radio-Loud QSO Candidate in COSMOS-Web

Authors:Erini Lambrides, Marco Chiaberge, Arianna Long, Daizhong Liu, Hollis B. Akins, Andrew F. Ptak, Irham Taufik Andika, Alessandro Capetti, Caitlin M. Casey, Jaclyn B. Champagne, Katherine Chworowsky, Olivia R. Cooper, Xuheng Ding, Andreas L. Faisst, Maximilien Franco, Steven Gillman, Ghassem Gozaliasl, Kirsten R. Hall, Santosh Harish, Christopher C. Hayward, Michaela Hirschmann, Taylor A. Hutchison, Knud Jahnke, Shuowen Jin, Jeyhan S. Kartaltepe, Anton M. Koekemoer, Vasily Kokorev, Sinclaire M. Manning, Crystal L. Martin, Jed McKinney, Colin Norman, Masafusa Onoue, Brant E. Robertson, Marko Shuntov, John D. Silverman, Massimo Stiavelli, Benny Trakhtenbrot, Eleni Vardoulaki, Jorge A. Zavala, Natalie Allen, Olivier Ilbert, Henry Joy McCracken, Louise Paquereau, Jason Rhodes, Sune Toft

Abstract: In this letter, we report the discovery of the highest redshift, heavily obscured, radio-loud QSO candidate selected using JWST NIRCam/MIRI, mid-IR, sub-mm, and radio imaging in the COSMOS-Web field. Using multi-frequency radio observations and mid-IR photometry, we identify a powerful, radio-loud (RL), growing supermassive black hole (SMBH) with significant spectral steepening of the radio SED ($f_{1.32 \mathrm{GHz}} \sim 2$ mJy, $q_{24\mu m} = -1.1$, $\alpha_{1.32-3\mathrm{GHz}}=-1.2$, $\Delta \alpha = -0.4$). In conjunction with ALMA, deep ground-based observations, ancillary space-based data, and the unprecedented resolution and sensitivity of JWST, we find no evidence of QSO contribution to the UV/optical/NIR data and thus infer heavy amounts of obscuration (N$_{\mathrm{H}} > 10^{23}$ cm$^{-2}$). Using the wealth of deep UV to sub-mm photometric data, we report a singular solution photo-z of $z_\mathrm{phot}$ = 7.65$^{+0.4}_{-0.3}$ and estimate an extremely massive host-galaxy ($\log M_{\star} = 11.92 \pm 0.06\,\mathrm{M}_{\odot}$). This source represents the furthest known obscured RL QSO candidate, and its level of obscuration aligns with the most representative but observationally scarce population of QSOs at these epochs.

4.Initial conditions of star formation at $\lesssim$2000 au: physical structure and NH$_{3}$ depletion of three early-stage cores

Authors:Yuxin Lin, Silvia Spezzano, Jaime E. Pineda, Jorma Harju, Anika Schmiedeke, Sihan Jiao, Hauyu Baobab Liu, Paola Caselli

Abstract: Pre-stellar cores represent a critical evolutionary phase in low-mass star formation. We aim to unveil the detailed thermal structure and density distribution of three early-stage cores, starless core L1517B, and prestellar core L694-2 and L429, with the high angular resolution observations of the NH$_{3}$ (1,1) and (2,2) inversion transitions obtained with VLA and GBT. In addition, we explore where/if NH$_{3}$ depletes in the central regions. Applying the mid-infrared extinction method to the $\textit{Spitzer}$ 8$~\mu$m map we obtain a high angular resolution hydrogen column density map, and derive the gas density profile to assess the variation of NH$_{3}$ abundance as a function of gas volume density. The measured temperature profiles of L429 and L1517B show a minor decrease towards the core center, dropping from $\sim$9\~K to below 8\~K, and $\sim$11 K to 10 K, while L694-2 has a rather uniform temperature distribution around $\sim$9 K. Among the three cores, L429 has the highest central gas density, close to sonic velocity line-width, and largest localised velocity gradient, all indicative of an advanced evolutionary stage. We resolve that the abundance of NH$_{3}$ becomes two times lower in the central region of L429, occurring around a gas density of 4.4$\times$10$^{4}$$~cm^{-3}$. Compared to Ophiuchus/H-MM1 which shows an even stronger drop of the NH$_{3}$ abundance at 2$\times$10$^{5}$$~cm^{-3}$, the abundance variations of the three cores plus Ophiuchus/H-MM1 suggest a progressive NH$_{3}$ depletion with increasing central density of the core.

5.Tracing Dense Gas in Six Resolved GMCs of the Andromeda Galaxy

Authors:Jan Forbrich, Charles J. Lada, Jérôme Pety, Glen Petitpas

Abstract: We present dense-gas--tracing molecular observations of six resolved Giant Molecular Clouds (GMCs) in the Andromeda Galaxy (M31). Using the NOEMA interferometer, we observed the transitions of HCN(1-0), HCO$^+$(1-0), and HNC(1-0), as well as $^{13}$CO(1-0) and 100 GHz continuum emission. This complements our earlier work with the Submillimeter Array (SMA), including resolved dust continuum detections of these clouds at 230 GHz. In this work, we first compare different continuum measurements to conclude that the average free-free contamination of the observed flux is 71% at 3 mm but only 13% at 1 mm, confirming that emission at 3 mm is less reliable than that at 1 mm for calculating dust masses of star-forming clouds. While the $^{13}$CO emission is more extended than both HCN and HCO$^+$ emission, which in turn is more extended than HNC emission, we find that both HCN and HCO$^+$ are spatially coincident with, and similarly extended as, the 230 GHz dust emission. This suggests that both the 230 GHz dust continuum and most importantly the HCN emission traces the dense gas component of these GMCs. From comparison of the molecular emission with dust masses derived from the 230 GHz continuum emission, we obtain the first direct measurements of the dust-mass-to-light ratios ($\alpha^\prime_{HCN}$ and $\alpha^\prime_{HCO^+}$) in GMCs of an external galaxy. For HCN, the result is broadly similar to a measurement in the local Perseus cloud suggesting that these are indeed dense gas conversion factors. A larger cloud sample will be required to assess whether HCN is tracing comparable cloud-scale density regimes across the environments of M31.

1.Predicting the Yields of $z$ > 6.5 Quasar Surveys in the Era of Roman and Rubin

Authors:Wei Leong Tee, Xiaohui Fan, Feige Wang, Jinyi Yang, Sangeeta Malhotra, James E. Rhoads

Abstract: Around 70 $z>6.5$ luminous quasars have been discovered, strongly biased toward the bright end, thus not providing a comprehensive view on quasar abundance beyond cosmic dawn. We present the predicted results of Roman/Rubin high-redshift quasar survey, yielding 3 times more, $2-4$ magnitudes deeper quasar samples, probing high-redshift quasars across broad range of luminosities, especially faint quasars at $L_\mathrm{bol}\sim 10^{10}\;L_{\odot}$ or $M_\mathrm{1450} \sim-22$ that are currently poorly explored. We include high-$z$ quasars, galactic dwarfs and low-$z$ compact galaxies with similar colors as quasar candidates. We create mock catalogs based on population models to evaluate selection completeness and efficiency. We utilize classical color dropout method in $z$ and $Y$ bands to select primary quasar candidates, followed up with Bayesian selection method to identify quasars. We show that overall selection completeness $> 80\%$ and efficiency $\sim 10\%$ at $6.5<z<9$, with 180 quasars at $z>6.5$, 20 at $z > 7.5$ and 2 at $z > 8.5$. The quasar yields depend sensitively on the assumed quasar luminosity shape and redshift evolution. Brown dwarf rejection through proper motion up to 50$\%$ can be made for stars brighter than 25 mag, low-$z$ galaxies dominate at fainter magnitude. Our results show that Roman/Rubin are able to discover a statistical sample of the earliest and faintest quasars in the Universe. The new valuable datasets worth follow up studies with James Webb Space Telescope and Extremely Large Telescopes, to determine quasar luminosity function faint end slope and constraint the supermassive black holes growth in the early Universe.

2.Constraining Circumgalactic Turbulence with QSO Absorption-line Measurements

Authors:Brad Koplitz, Edward Buie II, Evan Scannapieco

Abstract: Our knowledge of the circumgalactic medium (CGM) is mostly based on quasar absorption-line measurements. These have uncovered a multiphase medium that is likely highly turbulent, but constraints of this turbulence are limited to measurements of the non-thermal width of absorption-line components ($b_{turb}$) and the line-of-sight velocity dispersion between components ($\sigma_{LOS}$). Here we analyze a suite of CGM simulations to determine how well these indirect measures are related to the underlying CGM. Our simulations track the non-equilibrium evolution of all commonly observed ions, and consist of two main types: small-scale simulations of regions of homogeneous CGM turbulence and global simulations of inhomogeneous turbulence throughout a galactic halo. From each simulation, we generate mock spectra of Si II, Si IV, C IV, and O VI, which allow us to directly compare $b_{turb}$ and $\sigma_{LOS}$ to the true line-of-sight turbulence ($\sigma_{1D}$). In the small-scale simulations, $b_{turb}$ is only weakly correlated with $\sigma_{1D}$, likely because it measures random motions within individual warm CGM clouds, which do not sample the overall random motions. Meanwhile, $\sigma_{LOS}$ and $\sigma_{1D}$ are strongly correlated, with $\sigma_{1D}\approx\sigma_{LOS}+10$ km s$^{-1}$ in the densest regions we simulated, though, the strength of this correlation depended weakly on the gas phase being probed. Our large-scale simulations also indicate that $b_{turb}$ and $\sigma_{1D}$ are largely uncorrelated, and that $\sigma_{1D}\approx\sigma_{LOS}+10$ kms$^{-1}$ on average, although it varies along individual sightlines. Moreover, the $\sigma_\mathrm{LOS}$ distributions from our global simulations are similar to recent observations, suggesting that this quantity may provide useful constraints on circumgalactic turbulence regardless of the axis probed.

1.Probing magnetic fields in the circumgalactic medium using polarization data from MIGHTEE

Authors:K. Böckmann, M. Brüggen, V. Heesen, A. Basu, S. P. O'Sullivan, I. Heywood, M. Jarvis, A. Scaife, J. Stil, R. Taylor, N. J. Adams, R. A. A. Bowler, M. N. Tudorache

Abstract: The detection and study of magnetic fields surrounding galaxies is important to understand galaxy evolution since magnetic fields are tracers for dynamical processes in the circumgalactic medium (CGM) and can have a significant impact on the evolution of the CGM. The Faraday rotation measure (RM) of the polarized light of background radio sources passing through the magnetized CGM of intervening galaxies can be used as a tracer for the strength and extent of magnetic fields around galaxies. We use rotation measures observed by the MIGHTEE-POL (MeerKAT International GHz Tiered Extragalactic Exploration POLarisation) survey by MeerKAT in the XMM-LSS and COSMOS fields to investigate the RM around foreground star-forming galaxies. We use spectroscopic catalogs of star-forming and blue cloud galaxies to measure the RM of MIGHTEE-POL sources as a function of the impact parameter from the intervening galaxy. We then repeat this procedure using a deeper galaxy catalog with photometric redshifts. For the spectroscopic star-forming sample we find a redshift-corrected |RM| excess of 5.6 +/- 2.3 rad m-2 which corresponds to a 2.5 sigma significance around galaxies with a median redshift of z = 0.46 for impact parameters below 130 kpc only selecting the intervenor with the smallest impact parameter. Making use of a photometric galaxy catalog and taking into account all intervenors with Mg < -13.6 mag, the signal disappears. We find no indication for a correlation between redshift and RM, nor do we find a connection between the total number of intervenors to the total |RM| . We have presented tentative evidence that the CGM of star-forming galaxies is permeated by coherent magnetic fields within the virial radius. We conclude that mostly bright, star-forming galaxies with impact parameters less than 130 kpc significantly contribute to the RM of the background radio source.

2.Rest-Frame Near-Infrared Radial Light Profiles up to z=3 from JWST/NIRCam: Wavelength Dependence of the Sérsic Index

Authors:Marco Martorano, Arjen van der Wel, Eric F. Bell, Marijn Franx, Katherine E. Whitaker, Angelos Nersesian, Sedona H. Price, Maarten Baes, Katherine A. Suess, Erica J. Nelson, Tim B. Miller, Rachel Bezanson, Gabriel Brammer

Abstract: We examine the wavelength dependence of radial light profiles based on S\'ersic index $n$ measurements of 1067 galaxies with M$_*\geq$ 10$^{9.5}$M$_\odot$ and in the redshift range $0.5 < z < 3$. The sample and rest-frame optical light profiles are drawn from CANDELS$+$3D-HST; rest-frame near-infrared light profiles are inferred from CEERS JWST/NIRCam imaging. $n$ shows only weak dependence on wavelength, regardless of redshift, galaxy mass and type: on average, star-forming galaxies have $n = 1-1.5$ and quiescent galaxies have $n = 3-4$ in the rest-frame optical and near-infrared. The strong correlation at all wavelengths between $n$ and star-formation activity implies a physical connection between the radial stellar mass profile and star-formation activity. The main caveat is that the current sample is too small to discern trends for the most massive galaxies (M$_* > 10^{11}M_\odot$).

3.Looking into the faintEst WIth MUSE (LEWIS): on the nature of ultra-diffuse galaxies in the Hydra-I cluster.I. Project description and preliminary results

Authors:Enrichetta Iodice, Michael Hilker, Goran Doll, Marco Mirabile, Chiara Buttitta, Johanna Hartke, Steffen Mieske, Michele Cantiello, Giuseppe D'Ago, Duncan A. Forbes, Marco Gullieuszik, Marina Rejkuba, Marilena Spavone, Chiara Spiniello, Magda Arnaboldi, Enrico M. Corsini, Laura Greggio, Jesus Falcón-Barroso, Katja Fahrion, Jacopo Fritz, Antonio La Marca, Maurizio Paolillo, Maria Angela Raj, Roberto Rampazzo, Marc Sarzi, Giulio Capasso

Abstract: Looking into the faintEst WIth MUSE (LEWIS) is an ESO large observing programme aimed at obtaining the first homogeneous integral-field spectroscopic survey of 30 extremely low-surface brightness (LSB) galaxies in the Hydra I cluster of galaxies, with MUSE at ESO-VLT. The majority of LSB galaxies in the sample (22 in total) are ultra-diffuse galaxies (UDGs). The distribution of systemic velocities Vsys ranges between 2317 km/s and 5198 km/s and is centred on the mean velocity of Hydra I (Vsys = 3683 $\pm$ 46 km/s). Considering the mean velocity and the velocity dispersion of the cluster, 17 out of 20 targets are confirmed cluster members. To assess the quality of the data and demonstrate the feasibility of the science goals, we report the preliminary results obtained for one of the sample galaxies, UDG11. For this target, we derived the stellar kinematics, including the 2-dimensional maps of line-of-sight velocity and velocity dispersion, constrained age and metallicity, and studied the globular cluster (GC) population hosted by the UDG. Results are compared with the available measurements for UDGs and dwarf galaxies in literature. By fitting the stacked spectrum inside one effective radius, we find that UDG11 has a velocity dispersion $\sigma = 20 \pm 8$ km/s, it is old ($10\pm1$ Gyr), metal-poor ([M/H]=-1.17$\pm$0.11 dex) and has a total dynamical mass-to-light ratio M$/L_V\sim 14$, comparable to those observed for classical dwarf galaxies. The spatially resolved stellar kinematics maps suggest that UDG11 does not show a significant velocity gradient along either major or minor photometric axes. We find two GCs kinematically associated with UDG11. The estimated total number of GCs in UDG11, corrected for the spectroscopic completeness limit, is $N_{GC}= 5.9^{+2.2}_ {-1.8}$, which corresponds to a GC specific frequency of $S_N = 8.4^{+3.2}_{-2.7}$.

4.Ultra diffuse galaxies in the Hydra I cluster from the LEWIS Project: Phase-Space distribution and globular cluster richness

Authors:Duncan Forbes, Jonah Gannon, Enrichetta Iodice, Michael Hilker, Goran Doll, Chiara Buttitta, Antonio La Marca, Magda Arnaboldi, Michele Cantiello, G. D'Ago, Jesus Falcon Barroso, Laura Greggio, Marco Gullieuszik, Johanna Hartke, Steffen Mieske, Marco Mirabile, Roberto Rampazzo, Marina Rejkuba, Marilena Spavone, Chiara Spiniello, Giulio Capasso

Abstract: Although ultra diffuse galaxies (UDGs) are found in large numbers in clusters of galaxies, the role of the cluster environment in shaping their low surface brightness and large sizes is still uncertain. Here we examine a sample of UDGs in the Hydra I cluster (D = 51 Mpc) with new radial velocities obtained as part of the LEWIS (Looking into the faintest with MUSE) project using VLT/MUSE data. Using a phase-space, or infall diagnostic, diagram we compare the UDGs to other known galaxies in the Hydra I cluster and to UDGs in other clusters. The UDGs, along with the bulk of regular Hydra I galaxies, have low relative velocities and are located near the cluster core, and thus consistent with very early infall into the cluster. Combining with literature data, we do not find the expected trend of GC-rich UDGs associated with earlier infall times. This result suggests that quenching mechanisms other than cluster infall should be further considered, e.g. quenching by strong feedback or in cosmic sheets and filaments. Tidal stripping of GCs in the cluster environment also warrants further modelling.

5.Constraining the assembly time of the stellar haloes of nearby Milky Way-mass galaxies through AGB populations

Authors:Benjamin Harmsen, Eric F. Bell, Richard D'Souza, Antonela Monachesi, Roelof S. de Jong, Adam Smercina, In Sung Jang, Benne W. Holwerda

Abstract: The star formation histories (SFHs) of galactic stellar haloes offer crucial insights into the merger history of the galaxy and the effects of those mergers on their hosts. Such measurements have revealed that while the Milky Way's most important merger was 8-10 Gyr ago, M31's largest merger was more recent, within the last few Gyr. Unfortunately, the required halo SFH measurements are extremely observationally expensive outside of the Local Group. Here we use asymptotic giant branch (AGB) stars brighter than the tip of the red giant branch (RGB) to constrain stellar halo SFHs. Both stellar population models and archival datasets show that the AGB/RGB ratio constrains the time before which 90% of the stars formed, $t_{90}$. We find AGB stars in the haloes of three highly-inclined roughly Milky Way-mass galaxies with resolved star measurements from the Hubble Space Telescope; this population is most prominent in the stellar haloes of NGC 253 and NGC 891, suggesting that their stellar haloes contain stars born at relatively late times, with inferred $t_{90}\sim 6\pm1.5$Gyr. This ratio also varies from region to region, tending towards higher values along the major axis and in tidal streams or shells. By combining our measurements with previous constraints, we find a tentative anticorrelation between halo age and stellar halo mass, a trend that exists in models of galaxy formation but has never been elucidated before, i.e, the largest stellar haloes of Milky-Way mass galaxies were assembled more recently.

6.UNCOVER: A NIRSpec Census of Lensed Galaxies at z=8.50-13.08 Probing a High AGN Fraction and Ionized Bubbles in the Shadow

Authors:Seiji Fujimoto, Bingjie Wang, John Weaver, Vasily Kokorev, Hakim Atek, Rachel Bezanson, Ivo Labbe, Gabriel Brammer, Jenny E. Greene, Iryna Chemerynska, Pratika Dayal, Anna de Graaff, Lukas J. Furtak, Pascal A. Oesch, David J. Setton, Sedona H. Price, Tim B. Miller, Christina C. Williams, Katherine E. Whitaker, Adi Zitrin, Sam E. Cutler, Joel Leja, Richard Pan, Dan Coe, Pieter van Dokkum, Robert Feldmann, Yoshinobu Fudamoto, Andy D. Goulding, Gourav Khullar, Danilo Marchesini, Michael Maseda, Themiya Nanayakkara, Erica J. Nelson, Renske Smit, Mauro Stefanon, Andrea Weibel

Abstract: We present JWST NIRSpec prism spectroscopy of gravitationally lensed galaxies at $z\gtrsim9$ found behind the massive galaxy cluster Abell 2744 in the UNCOVER Cycle 1 Treasury Program. We confirm the source redshift via emission lines and/or the Ly$\alpha$ break feature for ten galaxies at z=8.50-13.08 down to $M_{\rm UV}=-17.3$. We achieve a high confirmation rate of 100\% for $z>9$ candidates reported in Atek et al. (2023). Using six sources with multiple emission line detections, we find that the offset of the redshift estimates between the lines and the Ly$\alpha$ break alone with prism can be as large as $\pm0.2$, raising caution in designing future follow-up spectroscopy for the break-only sources. With spec-$z$ confirmed sources in UNCOVER and the literature, we derive lower limits on the rest-frame ultraviolet (UV) luminosity function (LF) at $z\simeq9$-12 and find these lower limits to be consistent with recent photometric measurements. We identify at least two unambiguous and several possible active galactic nucleus (AGN) systems based on X-ray emission, broad line (BL) H$\beta$, high ionization line (e.g., NIV]1487, CIV1549) detections, and excess in UVLF. This requires the AGN LFs at $z\simeq$ 9-10 to be comparable or even higher than the X-ray AGN LF estimated at $z\sim6$ and indicates a plausible cause of the high abundance of $z>9$ galaxies claimed in recent photometric studies may be AGNs. One UV-luminous source is confirmed at the same redshift as a dusty BL AGN at $z=8.50$ with a physical separation of 380 kpc in the source plane. These two sources show blueward Ly$\alpha$ line or continuum emission, suggesting that they reside in the same ionized bubble with a radius of $7.56\pm0.10$ pMpc. Our results imply that AGNs have a non-negligible contribution to cosmic reionization.

7.UNCOVER: A NIRSpec Identification of a Broad Line AGN at z = 8.50

Authors:Vasily Kokorev, Seiji Fujimoto, Ivo Labbe, Jenny E. Greene, Rachel Bezanson, Pratika Dayal, Erica J. Nelson, Hakim Atek, Gabriel Brammer, Iryna Chemerynska, Sam E. Cutler, Robert Feldmann, Yoshinobu Fudamoto, Lukas J. Furtak, Andy D. Goulding, Anna de Graaff, Joel Leja, Danilo Marchesini, Tim B. Miller, Themiya Nanayakkara, Pascal Oesch, Richard Pan, Sedona H. Price, David J. Setton, Renske Smit, Mauro Stefanon, Bingjie Wang, John R. Weaver, Katherine E. Whitaker, Christina C. Williams, Adi Zitrin

Abstract: Deep observations with JWST have revealed an emerging population of red point-like sources that could provide a link between the postulated supermassive black hole seeds and observed quasars. In this work we present a JWST/NIRSpec spectrum from the JWST Cycle 1 UNCOVER Treasury survey, of a massive accreting black hole at $z=8.50$, displaying a clear broad-line component as inferred from the H$\beta$ line with FWHM = $3439\pm413$ km s$^{-1}$, typical of the broad line region of an active galactic nucleus (AGN). The AGN nature of this object is further supported by high ionization, as inferred from emission lines, and a point-source morphology. We compute the black hole mass of log$_{10}(M_{\rm BH}/M_\odot)=8.17\pm0.42$, and a bolometric luminosity of $L_{\rm bol}\sim6.6\times10^{45}$ erg s$^{-1}$. These values imply that our object is accreting at $\sim 40\%$ of the Eddington limit. Detailed modeling of the spectral energy distribution in the optical and near-infrared, together with constraints from ALMA, indicate an upper limit on the stellar mass of log$_{10}(M_{\rm *}/M_\odot)<8.7$, which would lead to an unprecedented ratio of black hole to host mass of at least $\sim 30 \%$. This is orders of magnitude higher compared to the local QSOs, but is consistent with recent AGN studies at high redshift with JWST. This finding suggests that a non-negligible fraction of supermassive black holes either started out from massive seeds and/or grew at a super-Eddington rate at high redshift. Given the predicted number densities of high-$z$ faint AGN, future NIRSpec observations of larger samples will allow us to further investigate the galaxy-black hole co-evolution in the early Universe.

8.The Panchromatic Hubble Andromeda Treasury: Triangulum Extended Region (PHATTER). V. The Structure of M33 in Resolved Stellar Populations

Authors:Adam Smercina, Julianne J. Dalcanton, Benjamin F. Williams, Meredith J. Durbin, Margaret Lazzarini, Eric F. Bell, Yumi Choi, Andrew Dolphin, Karoline Gilbert, Puragra Guhathakurta, Eric W. Koch, Hans-Walter Rix, Erik Rosolowsky, Anil Seth, Evan D. Skillman, Daniel R. Weisz

Abstract: We present a detailed analysis of the the structure of the Local Group flocculent spiral galaxy M33, as measured using the Panchromatic Hubble Andromeda Treasury Triangulum Extended Region (PHATTER) survey. Leveraging the multiwavelength coverage of PHATTER, we find that the oldest populations are dominated by a smooth exponential disk with two distinct spiral arms and a classical central bar $-$ completely distinct from what is seen in broadband optical imaging, and the first-ever confirmation of a bar in M33. We estimate a bar extent of $\sim$1 kpc. The two spiral arms are asymmetric in orientation and strength, and likely represent the innermost impact of the recent tidal interaction responsible for M33's warp at larger scales. The flocculent multi-armed morphology for which M33 is known is only visible in the young upper main sequence population, which closely tracks the morphology of the ISM. We investigate the stability of M33's disk, finding $Q{\sim}1$ over the majority of the disk. We fit multiple components to the old stellar density distribution and find that, when considering recent stellar kinematics, M33's bulk structure favors the inclusion of an accreted halo component, modeled as a broken power-law. The best-fit halo model has an outer power-law index of $-$3 and accurately describes observational evidence of M33's stellar halo from both resolved stellar spectroscopy in the disk and its stellar populations at large radius. Integrating this profile yields a total halo stellar mass of ${\sim}5{\times}10^8\ M_{\odot}$, giving a total stellar halo mass fraction of 16%, most of which resides in the innermost 2.5 kpc.

1.Distributions and Physical Properties of Molecular Clouds in the Third Galactic Quadrant: $l$ = [219.75, 229.75]$^\circ$ and $b$ = [-5.25, 5.25]$^\circ$

Authors:Yiwei Dong, Yan Sun, Ye Xu, Zehao Lin, Shuaibo Bian, Chaojie Hao, Dejian Liu, Yingjie Li, Ji Yang, Yang Su, Xin Zhou, Shaobo Zhang, Qing-Zeng Yan, Zhiwei Chen

Abstract: We present the results of an unbiased $^{12}$CO/$^{13}$CO/C$^{18}$O ($J$ = 1-0) survey in a portion of the third Galactic quadrant (TGQ): $l$ = [219.75, 229.75]$^\circ$ and $b$ = [-5.25, 5.25]$^\circ$. The high-resolution and high-sensitivity data sets help to unravel the distributions and physical properties of the molecular clouds (MCs) in the mapped area. In the LSR velocity range from -1 to 85 km/s, the molecular material successfully traces the Local, Perseus, and Outer arms. In the TGQ, the Outer arm appears to be more prominent than that in the second Galactic quadrant (SGQ), but the Perseus arm is not as conspicuous as that in the SGQ. A total of 1,502 $^{12}$CO, 570 $^{13}$CO, and 53 C$^{18}$O molecular structures are identified, spanning over $\sim2$ and $\sim6$ orders of magnitude in size and mass, respectively. Tight mass-radius correlations and virial parameter-mass anticorrelations are observable. Yet, it seems that no clear correlations between velocity dispersion and effective radius can be found over the full dynamic range. The vertical distribution of the MCs renders evident pictures of the Galactic warp and flare.

2.Preliminary Exploration of Areal Density of Angular Momentum for Spiral Galaxies

Authors:Lan Zhang, Feilu Wang, Xiangxiang Xue, David Salzmann, Baifei Shen, Zehao Zhong, Gang Zhao

Abstract: The specific angular momenta ($j_t$) of stars, baryons as a whole and dark matter haloes contain clues of vital importance about how galaxies form and evolve. Using a sample of 70 spiral galaxies, we perform a preliminary analysis of $j_t$, and introduce a new quantity, e.g., areal density of angular momentum (ADAM) ($j_t~M_\star/4R_d^2$) as an indication for the existence of jet in spiral galaxies. The percentage of spiral galaxies having jet(s) shows strong correlation with the ADAM, although the present sample is incomplete.

3.The molecular clouds in a section of the third Galactic quadrant: observational properties and chemical abundance ratio between CO and its isotopologues

Authors:Chen Wang, Haoran Feng, Ji Yang, Xuepeng Chen, Yang Su, Qing-Zeng Yan, Fujun Du, Yuehui Ma, Jiajun Cai

Abstract: We compare the observational properties between $^{12}$CO, $^{13}$CO, and C$^{18}$O and summarize the observational parameters based on 7069 clouds sample from the Milky Way Imaging Scroll Painting (MWISP) CO survey in a section of the third Galactic quadrant. We find that the $^{13}$CO angular area ($A_{\rm ^{13}CO}$) generally increases with that of $^{12}$CO ($A_{\rm ^{12}CO}$), and the ratio of $A_{\rm ^{13}CO}$ to $A_{\rm ^{12}CO}$ is 0.38 by linear fitting. We find that the $^{12}$CO and $^{13}$CO flux are tightly correlated as $F_{\rm ^{13}CO}~=~0.17~ F_{\rm ^{12}CO}$ with both fluxes calculated within the $^{13}$CO-bright region. This indicates that the abundance $X_{\rm ^{13}CO}$ is a constant to be 6.5$^{+0.1}_{-0.5}$ $\times 10^{-7}$ for all samples under assumption of local thermodynamic equilibrium (LTE). Additionally, we observed that the X-factor is approximately constant in large sample molecular clouds. Similarly, we find $F_{\rm C^{18}O}~=~0.11~F_{\rm ^{13}CO}$ with both fluxes calculated within C$^{18}$O-bright region, which indicates that the abundance ratios ${X_{\rm ^{13}CO}/X_{\rm C^{18}O}}$ stays the same value 9.7$^{+0.6}_{-0.8}$ across the molecular clouds under LTE assumption. The linear relationships of $F_{\rm ^{12}CO}$ vs. $F_{\rm ^{13}CO}$ and $F_{\rm ^{13}CO}$ vs. $F_{\rm C^{18}O}$ hold not only for the $^{13}$CO-bright region or C$^{18}$O-bright region, but also for the entire molecular cloud scale with lower flux ratio. The abundance ratio ${X_{\rm ^{13}CO}/X_{\rm C^{18}O}}$ inside clouds shows a strong correlation with column density and temperature. This indicates that the ${X_{\rm ^{13}CO}/X_{\rm C^{18}O}}$ is dominated by a combination of chemical fractionation, selectively dissociation, and self-shielding effect inside clouds.

4.A Search for Gas-Rich Dwarf Galaxies in the Local Universe with ALFALFA and the WIYN One Degree Imager

Authors:Katherine L. Rhode, Nicholas J. Smith, William F. Janesh, John J. Salzer, Elizabeth A. K. Adams, Martha P. Haynes, Steven Janowiecki, John M. Cannon

Abstract: We present results from an optical search for Local Group dwarf galaxy candidates associated with the Ultra-Compact High Velocity Clouds (UCHVCs) discovered by the ALFALFA neutral hydrogen survey. The ALFALFA UCHVCs are isolated, compact HI clouds with projected sizes, velocities, and estimated HI masses that suggest they may be nearby dwarf galaxies, but that have no clear counterpart in existing optical survey data. We observed 26 UCHVCs with the WIYN 3.5-m telescope and One Degree Imager (ODI) in two broadband filters and searched the images for resolved stars with properties that match those of stars in typical dwarf galaxies at distances <2.5 Mpc. We identify one promising dwarf galaxy candidate at a distance of ~570 kpc associated with the UCHVC AGC 268071, and five other candidates that may deserve additional follow-up. We carry out a detailed analysis of ODI imaging of a UCHVC that is close in both projected distance and radial velocity to the outer-halo Milky Way globular cluster Pal 3. We also use our improved detection methods to reanalyze images of five UCHVCs that were found to have possible optical counterparts during the first phase of the project, and confirm the detection of a possible stellar counterpart to the UCHVC AGC 249525 at an estimated distance of ~2 Mpc. We compare the optical and HI properties of the dwarf galaxy candidates to the results from recent theoretical simulations that model satellite galaxy populations in group environments, as well as to the observed properties of galaxies in and around the Local Group.

5.Detailed study of the Bootes field using 300-500 MHz uGMRT observations: Source Properties and radio--infrared correlations

Authors:Akriti Sinha, Abhirup Datta

Abstract: The dominant source of radio continuum emissions at low frequencies is synchrotron radiation, which originates from star-forming regions in disk galaxies and from powerful jets produced by active galactic nuclei (AGN). We studied the Bootes field using the upgraded Giant Meterwave Radio Telescope (uGMRT) at 400 MHz, achieving a central minimum off-source RMS noise of 35$\mu$Jy beam$^{-1}$ and a catalogue of 3782 sources in $\sim6$ sq. degrees of the sky. The resulting catalogue was compared to other radio frequency catalogues, and the corrected normalised differential source counts were derived. We use standard multi-wavelength techniques to classify the sources in star-forming galaxies (SFGs), radio-loud (RL) AGN, and radio-quiet (RQ) AGN that confirm a boost in the SFGs and RQ\,AGN AGN populations at lower flux levels. For the first time, we investigated the properties of the radio--IR relations at 400\,MHz in this field. The $L_{\rm 400 MHz}$--$L_{\rm TIR}$ relations for SFGs were found to show a strong correlation with non-linear slope values of $1.10\pm0.01$, and variation of $q_{\rm TIR}$ with $z$ is given as, $q_{\rm TIR} = (2.19 \pm 0.07)\ (1+z)^{-0.15 \pm 0.08}$. This indicates that the non-linearity of the radio--IR relations can be attributed to the mild variation of $q_{\rm TIR}$ values with $z$. The derived relationships exhibit similar behaviour when applied to LOFAR at 150 MHz and also at 1.4 GHz. This emphasises the fact that other parameters like magnetic field evolution with $z$ or the number densities of cosmic ray electrons can play a vital role in the mild evolution of $q$ values.

6.Dynamics of supermassive black hole triples in the ROMULUS25 cosmological simulation

Authors:Hauke Koehn, Andreas Just, Peter Berczik, Michael Tremmel

Abstract: For a pair of supermassive black holes (SMBHs) in the remnant of a dual galaxy merger, well-known models exist to describe their dynamical evolution until the final coalescence accompanied by the emission of a low-frequency gravitational wave (GW) signal. In this article, we investigate the dynamical evolution of three SMBH triple systems recovered from the ROMULUS25 cosmological simulation to explore common dynamical evolution patterns and assess typical coalescence times. For this purpose, we construct initial conditions from the ROMULUS25 data and perform high-resolution gravitodynamical \N-body simulations. We track the orbital evolution from the galactic inspiral to the formation of hard binaries at sub-parsec separation and use the observed hardening rates to project the time of coalescence. In all cases, the two heaviest black holes form an efficiently hardening binary that merges within fractions of the Hubble time. The lightest SMBH either gets ejected, forms a stable hierarchical triple system with the heavier binary, forms a hardening binary with the previously merged binary's remnant, or remains on a wide galactic orbit. The coalescence times of the lighter black holes are thus significantly longer than for the heavier binary, as they experience lower dynamical friction and stellar hardening rates. We observe the formation of hierarchical triples when the density profile of the galactic nucleus is sufficiently steep.

7.Little Red Dots or Brown Dwarfs? NIRSpec Confirmation of Three Brown Dwarfs Masquerading as NIRCam-Selected Highly-Reddened AGNs

Authors:Danial Langeroodi, Jens Hjorth

Abstract: Cold, substellar objects such as brown dwarfs have long been recognized as contaminants in color-selected samples of active galactic nuclei (AGNs). In particular, their near- to mid-infrared colors (1--5 $\mu$m) can closely resemble the V-shaped ($f_{\lambda}$) spectra of highly-reddened accreting supermassive black holes, the little red dots, especially at $6 < z < 7$. Recently, a NIRCam-selected sample of little red dots over 45 arcmin$^2$ has been followed-up with deep NIRSpec multi-object prism spectroscopy through the UNCOVER program. By investigating the acquired spectra, we identify three out of the 13 followed-up objects as brown dwarfs with temperatures between 650 and 1300 K and distances between 0.8 and 4.8 kpc. We identify the remaining 10 objects as extragalactic sources at $z_{\rm spec} > 3$. Given that three of these sources are the strongly lensed images of the same AGN (Abell2744-QSO1), we derive a brown dwarf contamination fraction of 27\% in this NIRCam-selection of little red dots. We find that in the near-infrared filters, brown dwarfs appear much bluer than the highly-reddened AGN, providing an avenue for distinguishing the two and compiling cleaner samples of photometrically-selected highly-reddened AGN.

1.Unveiling The Mysteries Of The Cosmos: An Overview Of Radio Astronomy And Its Profound Insights

Authors:Manjuleshwar Panda, Yogesh Chandra

Abstract: With its immensity and numerous mysteries waiting to be solved, the cosmos has always captivated humankind. A ground-breaking field that has given us a profound understanding of the mysteries of the cosmos is radio astronomy. This paper presents a comprehensive overview of radio astronomy, exploring its techniques, discoveries, and the profound insights it offers into celestial objects. Radio astronomy, which uses radio waves to analyse celestial phenomena, has completely changed how we think about the universe. This field has given us crucial information about the formation of stars, galaxies, and other celestial objects through the analysis of radio emissions. Radio astronomy has enabled researchers to study cosmic processes that are undetectable to the human eye by penetrating the furthest reaches of space. We explore radio astronomy techniques in this article, revealing how it can be used to see through interstellar dust and collect signals from the universe's furthest reaches. Pulsars, quasars, and cosmic microwave background radiation are significant discoveries that have helped astronomers understand dark matter and dark energy in great detail. We also look into how radio astronomy might be used in cosmology and astrophysics. In conclusion, radio astronomy has become a potent tool for solving the cosmos' riddles. Its capacity for the detection and analysis of radio emissions has produced a fundamental understanding of the beginnings and evolution of the universe. Radio astronomy continues to advance our understanding of the cosmos and arouses interest in additional cosmic research by shedding light on celestial objects that are invisible to the human eye.

2.The Accretion History of AGN: The Spectral Energy Distributions of X-ray Luminous AGN

Authors:Connor Auge, David Sanders, Ezequiel Treister, C. Megan Urry, Allison Kirkpatrick, Nico Cappelluti, Tonima Tasnim Ananna, Médéric Boquien, Mislav Baloković, Francesca Civano, Brandon Coleman, Aritra Ghosh, Jeyhan Kartaltepe, Michael Koss, Stephanie LaMassa, Stefano Marchesi, Alessandro Peca, Meredith Powell, Benny Trakhtenbrot, Tracey Jane Turner

Abstract: Spectral energy distributions (SEDs) from X-ray to far-infrared (FIR) wavelengths are presented for a sample of 1246 X-ray luminous active galactic nuclei (AGN; $L_{0.5-10\rm{keV}}>10^{43}$ erg s$^{-1}$), with $z_{\rm{spec}}<1.2$, selected from Stripe 82X, COSMOS, and GOODS-N/S. The rest-frame SEDs show a wide spread ($\sim2.5$ dex) in the relative strengths of broad continuum features at X-ray, ultraviolet (UV), mid-infrared (MIR), and FIR wavelengths. A linear correlation (log-log slope of 0.7$\pm0.04$) is found between $L_{\rm{MIR}}$ and $L_{\rm{X}}$. There is significant scatter in the relation between the $L_{\rm{UV}}$ and $L_{\rm{X}}$ due to heavy obscuration, however the most luminous and unobscured AGN show a linear correlation (log-log slope of 0.8$\pm0.06$) in the relation above this scatter. The relation between $L_{\rm{FIR}}$ and $L_{\rm{X}}$ is predominantly flat, but with decreasing dispersion at $L_{\rm{X}}>10^{44}$ erg s$^{-1}$. The ratio between the "galaxy subtracted" bolometric luminosity and the intrinsic $L_{\rm{X}}$ increases from a factor of $\sim$$10-70$ from log $L_{\rm{bol}}/{\rm(erg\; s}^{-1})=44.5-46.5$. Characteristic SED shapes have been determined by grouping AGN based on relative strengths of the UV and MIR emission. The average $L_{1\mu\rm{m}}$ is constant for the majority of these SED shapes, while AGN with the strongest UV and MIR emission have elevated $L_{1\mu\rm{m}}$, consistent with the AGN emission dominating their SEDs at optical and NIR wavelengths. A strong correlation is found between the SED shape and both the $L_{\rm{X}}$ and $L_{\rm{bol}}$, such that $L_{\rm{bol}}/L_{\rm{X}}=20.4\pm1.8$, independent of the SED shape. This is consistent with an evolutionary scenario of increasing $L_{\rm{bol}}$ with decreasing obscuration as the AGN blows away circumnuclear gas.

3.The first detection of SiC$_2$ in the interstellar medium

Authors:S. Massalkhi, I. Jiménez-Serra, J. Martín-Pintado, V. M. Rivilla, L. Colzi, S. Zeng, S. Martín, B. Tercero, P. de Vicente, M. A. Requena-Torres

Abstract: We report the first detection of SiC$_2$ in the interstellar medium. The molecule was identified through six rotational transitions toward G\,+0.693$-$0.027, a molecular cloud located in the Galactic center. The detection is based on a line survey carried out with the GBT, the Yebes 40m, and the IRAM 30m telescopes covering a range of frequencies from 12 to 276 GHz. We fit the observed spectra assuming local thermodynamic equilibrium and derive a column density of ($1.02\pm0.04)\times10^{13}$ cm$^{-2}$, which gives a fractional abundance of $7.5\times10^{-11}$ with respect to H$_2$, and an excitation temperature of $5.9\pm0.2$ K. We conclude that SiC$_2$ can be formed in the shocked gas by a reaction between the sputtered atomic silicon and C$_2$H$_2$, or it can be released directly from the dust grains due to disruption. We also search for other Si-bearing molecules and detect eight rotational transitions of SiS and four transitions of Si$^{18}$O. The derived fractional abundances are $3.9\times10^{-10}$ and $2.1\times10^{-11}$, respectively. All Si-bearing species toward G\,+0.693$-$0.027 show fractional abundances well below what is typically found in late-type evolved stars.

4.Parsec scales of carbon chain and complex organic molecules in AFGL 2591 and IRAS 20126

Authors:P. Freeman, S. Bottinelli, R. Plume, E. Caux, C. Monaghan, B. Mookerjea

Abstract: (Abridged) There is a diverse chemical inventory in protostellar regions leading to the classification of extreme types of systems. Warm carbon chain chemistry sources, for one, are the warm and dense regions near a protostar containing unsaturated carbon chain molecules. Since the presentation of this definition in 2008, there is a growing field to detect and characterise these sources. The details are lesser known in relation to hot cores and in high-mass star-forming regions -- regions of great importance in galactic evolution. To investigate the prevalence of carbon chain species and their environment in high-mass star-forming regions, we have conducted targeted spectral surveys of two sources in the direction of Cygnus X -- AFGL 2591 and IRAS 20126+4104 -- with the Green Bank Telescope and the IRAM 30m Telescope. We have constructed a Local Thermodynamic Equilibrium (LTE) model using the observed molecular spectra to determine the physical environment in which these molecules originate. We map both the observed spatial distribution and the physical parameters found from the LTE model. We also determine the formation routes of these molecules in each source using the three-phase NAUTILUS chemical evolution code. We detect several lines of propyne, CH$_3$CCH, and cyclopropenylidene, $c$-C$_3$H$_2$ as tracers of carbon chain chemistry, as well as several lines of formaldehyde, H$_2$CO, and methanol, CH$_3$OH, as a precursor and a tracer of complex organic molecule chemistry, respectively. We find excitation temperatures of 20-30 K for the carbon chains and 8-85 K for the complex organics. The CH$_3$CCH abundances are reproduced by a warm-up model, consistent with warm carbon chain chemistry, while the observed CH$_3$OH abundances require a shock mechanism sputtering the molecules into the gas phase.

5.Statistical association between the candidate repeating FRB 20200320A and a galaxy group

Authors:Masoud Rafiei-Ravandi, Kendrick M. Smith, D. Michilli, Ziggy Pleunis, Mohit Bhardwaj, Matt Dobbs, Gwendolyn M. Eadie, Emmanuel Fonseca, B. M. Gaensler, Jane Kaczmarek, Victoria M. Kaspi, Calvin Leung, Dongzi Li, Kiyoshi W. Masui, Ayush Pandhi, Aaron B. Pearlman, Mubdi Rahman, Paul Scholz, David C. Stenning

Abstract: We present results from angular cross-correlations between select samples of CHIME/FRB repeaters and galaxies in three photometric galaxy surveys, which have shown correlations with the first CHIME/FRB catalog containing repeating and nonrepeating sources: WISE$\times$SCOS, DESI-BGS, and DESI-LRG. We find a statistically significant correlation ($p$-value $<0.001$, after accounting for look-elsewhere factors) between a sample of repeaters with extragalactic DM $>395$ pc cm$^{-3}$ and WISE$\times$SCOS galaxies with redshift $z>0.275$. We demonstrate that the correlation arises surprisingly because of a statistical association between FRB 20200320A (extragalactic DM $\approx550$ pc cm$^{-3}$) and a galaxy group in the same dark matter halo at redshift $z\approx0.32$. Based on our results, we suggest incorporating galaxy group and cluster catalogs into direct host association pipelines for FRBs with $\lesssim1'$ localization precision, effectively utilizing the two-point information to constrain FRB properties such as their redshift. In addition, we find marginal evidence for a negative correlation at 99.4% CL between a sample of repeating FRBs with baseband data (median extragalactic DM $=354$ pc cm$^{-3}$) and DESI-LRG galaxies with redshift $0.3\le z<0.45$, suggesting that the repeaters might be more prone than apparent nonrepeaters to propagation effects due to intervening free electrons over angular scales $\sim0\mbox{$.\!\!^\circ$}5$.

6.Milliarcsecond Core Size Dependence of the Radio Variability of Blazars

Authors:Po Chih Hsu, Jun Yi Koay, Satoki Matsushita, Chorng-Yuan Hwang, Talvikki Hovatta, Sebastian Kiehlmann, Anthony Readhead, Walter Max-Moerbeck, Rodrigo Reeves

Abstract: Studying the long-term radio variability (timescales of months to years) of blazars enables us to gain a better understanding of the physical structure of these objects on sub-parsec scales, and the physics of super massive black holes. In this study, we focus on the radio variability of 1157 blazars observed at 15 GHz through the Owens Valley Radio Observatory (OVRO) Blazar Monitoring Program. We investigate the dependence of the variability amplitudes and timescales, characterized based on model fitting to the structure functions, on the milliarcsecond core sizes measured by Very Long Baseline Interferometry. We find that the most compact sources at milliarcsecond scales exhibit larger variability amplitudes and shorter variability timescales than more extended sources. Additionally, for sources with measured redshifts and Doppler boosting factors, the correlation between linear core sizes against variability amplitudes and intrinsic timescales are also significant. The observed relationship between variability timescales and core sizes is expected, based on light travel-time arguments. This variability vs core size relation extends beyond the core sizes measured at 15 GHz; we see significant correlation between the 15 GHz variability amplitudes (as well as timescales) and core sizes measured at other frequencies, which can be attributed to a frequency-source size relationship arising from the intrinsic jet structure. At low frequencies of 1 GHz where the core sizes are dominated by interstellar scattering, we find that the variability amplitudes have significant correlation with the 1 GHz intrinsic core angular sizes, once the scatter broadening effects are deconvoluted from the intrinsic core sizes.

7.A deep learning approach for the 3D reconstruction of dust density and temperature in star-forming regions

Authors:Victor F. Ksoll, Stefan Reissl, Ralf S. Klessen, Ian W. Stephens, Rowan J. Smith, Juan D. Soler, Alessio Traficante, Leonardo Testi, Patrick Hennebelle, Sergio Molinari

Abstract: Aims: We introduce a new deep learning approach for the reconstruction of 3D dust density and temperature distributions from multi-wavelength dust emission observations on the scale of individual star-forming cloud cores (<0.2 pc). Methods: We construct a training data set by processing cloud cores from the Cloud Factory simulations with the POLARIS radiative transfer code to produce synthetic dust emission observations at 23 wavelengths between 12 and 1300 $\mu$m. We simplify the task by reconstructing the cloud structure along individual lines of sight and train a conditional invertible neural network (cINN) for this purpose. The cINN belongs to the group of normalising flow methods and is able to predict full posterior distributions for the target dust properties. We test different cINN setups, ranging from a scenario that includes all 23 wavelengths down to a more realistically limited case with observations at only seven wavelengths. We evaluate the predictive performance of these models on synthetic test data. Results: We report an excellent reconstruction performance for the 23-wavelengths cINN model, achieving median absolute relative errors of about 1.8% in $\log(n_{dust}/m^{-3})$ and 1% in $\log(T_{dust}/K)$, respectively. We identify trends towards overestimation at the low end of the density range and towards underestimation at the high end of both density and temperature, which may be related to a bias in the training data. Limiting coverage to a combination of only seven wavelengths, we still find a satisfactory performance with average absolute relative errors of about 3.3% and 2.5% in $\log(n_{dust}/m^{-3})$ and $\log(T_{dust}/K)$. Conclusions: This proof of concept study shows that the cINN-based approach for 3D reconstruction of dust density and temperature is very promising and even feasible under realistic observational constraints.

8.EPOCHS IX. When cosmic dawn breaks: Evidence for evolved stellar populations in $7 < z < 12$ galaxies from PEARLS GTO and public NIRCam imaging

Authors:James A. A. Trussler, Christopher J. Conselice, Nathan Adams, Duncan Austin, Leonardo Ferreira, Tom Harvey, Qiong Li, Aswin P. Vijayan, Stephen M. Wilkins, Rogier A. Windhorst, Rachana Bhatawdekar, Cheng Cheng, Dan Coe, Seth H. Cohen, Simon P. Driver, Brenda Frye, Norman A. Grogin, Nimish Hathi, Rolf A. Jansen, Anton Koekemoer, Madeline A. Marshall, Mario Nonino, Rafael Ortiz, Nor Pirzkal, Aaron Robotham, Russell E. Ryan Jr., Jordan C. J. D'Silva, Jake Summers, Scott Tompkins, Christopher N. A. Willmer, Haojing Yan

Abstract: The presence of evolved stars in high-redshift galaxies can place valuable indirect constraints on the onset of star formation in the Universe. Thus we use a combination of PEARLS GTO and public NIRCam photometric data to search for Balmer break candidate galaxies at $7 < z < 12$. We find that our Balmer break candidates at $z \sim 10.5$ tend to be older (115 Myr), have lower inferred [O III] + H$\beta$ emission line equivalent widths (120 \r{A}), have lower specific star formation rates (6 Gyr$^{-1}$) and redder UV slopes ($\beta = -1.8$) than our control sample of galaxies. However, these trends all become less strong at $z \sim 8$, where the F444W filter now probes the strong rest-frame optical emission lines, thus providing additional constraints on the current star formation activity of these galaxies. These weaker trends likely reflect the bursty nature of these Epoch of Reionisation galaxies, which can lead to a disconnect between their current star formation activity and SED profiles, and their more extended star formation history. We discuss how strong emission lines, the cumulative effect of weak emission lines, dusty continua and AGN can all contribute to the photometric excess seen in the rest-frame optical, thus mimicking the signature of a Balmer break. Additional medium-band imaging will thus be essential to more robustly identify Balmer break galaxies. However, the Balmer break alone cannot serve as a definitive proxy for the stellar age of galaxies, being complexly dependent on the star formation history. Ultimately, deep NIRSpec continuum spectroscopy and MIRI imaging will provide the strongest indirect constraints on the formation era of the first galaxies in the Universe, thereby revealing when cosmic dawn breaks.

9.Ionised gas kinematics and dynamical masses of $z\gtrsim6$ galaxies from JADES/NIRSpec high-resolution spectroscopy

Authors:Anna de Graaff, Hans-Walter Rix, Stefano Carniani, Katherine A. Suess, Stéphane Charlot, Emma Curtis-Lake, Santiago Arribas, William M. Baker, Kristan Boyett, Andrew J. Bunker, Alex J. Cameron, Jacopo Chevallard, Mirko Curti, Daniel J. Eisenstein, Marijn Franx, Kevin Hainline, Ryan Hausen, Zhiyuan Ji, Benjamin D. Johnson, Gareth C. Jones, Roberto Maiolino, Michael V. Maseda, Erica Nelson, Eleonora Parlanti, Tim Rawle, Brant Robertson, Sandro Tacchella, Hannah Übler, Christina C. Williams, Christopher N. A. Willmer, Chris Willott

Abstract: We explore the kinematic gas properties of six $5.5<z<7.4$ galaxies in the JWST Advanced Deep Extragalactic Survey (JADES), using high-resolution JWST/NIRSpec multi-object spectroscopy of the rest-frame optical emission lines [OIII] and H$\alpha$. The objects are small and of low stellar mass ($\sim 1\,$kpc; $M_*\sim10^{7-9}\,{\rm M_\odot}$), less massive than any galaxy studied kinematically at $z>1$ thus far. The cold gas masses implied by the observed star formation rates are $\sim 10\times$ larger than the stellar masses. We find that their ionised gas is spatially resolved by JWST, with evidence for broadened lines and spatial velocity gradients. Using a simple thin-disc model, we fit these data with a novel forward modelling software that accounts for the complex geometry, point spread function, and pixellation of the NIRSpec instrument. We find the sample to include both rotation- and dispersion-dominated structures, as we detect velocity gradients of $v(r_{\rm e})\approx100-150\,{\rm km\,s^{-1}}$, and find velocity dispersions of $\sigma_0\approx 30-70\,{\rm km\,s^{-1}}$ that are comparable to those at cosmic noon. The dynamical masses implied by these models ($M_{\rm dyn}\sim10^{9-10}\,{\rm M_\odot}$) are larger than the stellar masses by up to a factor 40, and larger than the total baryonic mass (gas + stars) by a factor of $\sim 3$. Qualitatively, this result is robust even if the observed velocity gradients reflect ongoing mergers rather than rotating discs. Unless the observed emission line kinematics is dominated by outflows, this implies that the centres of these galaxies are dark-matter dominated or that star formation is $3\times$ less efficient, leading to higher inferred gas masses.

10.Near-Infrared Flux Distribution of Sgr A* from 2005-2022: Evidence for an Enhanced Accretion Episode in 2019

Authors:Grant C. Weldon UCLA, Tuan Do UCLA, Gunther Witzel Max Planck Institute for Radio Astronomy, Andrea M. Ghez UCLA, Abhimat K. Gautam UCLA, Eric E. Becklin UCLA, Mark R. Morris UCLA, Gregory D. Martinez UCLA, Shoko Sakai UCLA, Jessica R. Lu UC Berkeley, Keith Matthews Caltech, Matthew W. Hosek Jr. UCLA, Zoë Haggard UCLA

Abstract: Sgr A* is the variable electromagnetic source associated with accretion onto the Galactic center supermassive black hole. While the near-infrared (NIR) variability of Sgr A* was shown to be consistent over two decades, unprecedented activity in 2019 challenges existing statistical models. We investigate the origin of this activity by re-calibrating and re-analyzing all of our Keck Observatory Sgr A* imaging observations from 2005-2022. We present light curves from 69 observation epochs using the NIRC2 imager at 2.12 $\mu$m with laser guide star adaptive optics. These observations reveal that the mean luminosity of Sgr A* increased by a factor of $\sim$3 in 2019, and the 2019 light curves had higher variance than in all time periods we examined. We find that the 2020-2022 flux distribution is statistically consistent with the historical sample and model predictions, but with fewer bright measurements above 0.6 mJy at the $\sim$2$\sigma$ level. Since 2019, we have observed a maximum $K_s$ (2.2 $\mu$m) flux of 0.9 mJy, compared to the highest pre-2019 flux of 2.0 mJy and highest 2019 flux of 5.6 mJy. Our results suggest that the 2019 activity was caused by a temporary accretion increase onto Sgr A*, possibly due to delayed accretion of tidally-stripped gas from the gaseous object G2 in 2014. We also examine faint Sgr A* fluxes over a long time baseline to search for a quasi-steady quiescent state. We find that Sgr A* displays flux variations over a factor of $\sim$500, with no evidence for a quiescent state in the NIR.

11.CEERS Key Paper VII: JWST/MIRI Reveals a Faint Population of Galaxies at Cosmic Noon Unseen by Spitzer

Authors:Allison Kirkpatrick, Guang Yang, Aurelien Le Bail, Greg Troiani, Eric F. Bell, Nikko J. Cleri, David Elbaz, Steven L. Finkelstein, Nimish P. Hathi, Michaela Hirschmann, Benne W. Holwerda, Dale D. Kocevski, Ray A. Lucas, Jed McKinney, Casey Papovich, Pablo G. Perez-Gonzalez, Alexander de la Vega, Micaela B. Bagley, Emanuele Daddi, Mark Dickinson, Henry C. Ferguson, Adriano Fontana, Andrea Grazian, Norman A. Grogin, Pablo Arrabal Haro, Jeyhan S. Kartaltepe, Lisa J. Kewley, Anton M. Koekemoer, Jennifer M. Lotz, Laura Pentericci, Nor Pirzkal, Swara Ravindranath, Rachel S. Somerville, Jonathan R. Trump, Stephen M. Wilkins, L. Y. Aaron Yung

Abstract: The Cosmic Evolution Early Release Science (CEERS) program observed the Extended Groth Strip with the Mid-Infrared Instrument (MIRI) on the James Webb Space Telescope (JWST) in 2022. In this paper, we discuss the four MIRI pointings that observed with longer wavelength filters, including F770W, F1000W, F1280W, F1500W, F1800W, and F2100W. We compare the MIRI galaxies with the Spitzer/MIPS 24$\mu$m population in the EGS field. We find that MIRI can observe an order of magnitude deeper than MIPS in significantly shorter integration times, attributable to JWST's much larger aperture and MIRI's improved sensitivity. MIRI is exceptionally good at finding faint ($L_{\rm IR}<10^{10} L_\odot$) galaxies at $z\sim1-2$. We find that a significant portion of MIRI galaxies are "mid-IR weak"--they have strong near-IR emission and relatively weaker mid-IR emission, and most of the star formation is unobscured. We present new IR templates that capture how the mid-IR to near-IR emission changes with increasing infrared luminosity. We present two color-color diagrams to separate mid-IR weak galaxies and active galactic nuclei (AGN) from dusty star-forming galaxies and find that these color diagrams are most effective when used in conjunction with each other. We present the first number counts of 10$\mu$m sources and find that there are $\lesssim10$ IR AGN per MIRI pointing, possibly due to the difficulty of distinguishing AGN from intrinsically mid-IR weak galaxies (due to low metallicities or low dust content). We conclude that MIRI is most effective at observing moderate luminosity ($L_{\rm IR}=10^9-10^{10}L_\odot$) galaxies at $z=1-2$, and that photometry alone is not effective at identifying AGN within this faint population.

12.The compactness of ultra faint dwarf galaxies : a new challenge ?

Authors:Yves Revaz EPFL

Abstract: So far, numerical simulations of ultra-faint dwarf galaxies (UFDs) failed to properly reproduce the observed size-luminosity relation. In particular, no hydro-dynamical-run managed to form UFDs with a half light radius as small as 30 pc as seen in several UFD candidates. We tackle this problem by developing a simple but numerically clean and powerful method in which predictions of the stellar content of UFDs from LCDM cosmological hydro-dynamical-simulations is combined with very high resolution dark matter only runs. This method allows to trace the build-up history of UFDs and determine the impact of the merger of building-block objects on their final size. We found that, while no UFDs more compact than 20 pc can be formed, slightly larger system are reproduced only if all member stars are issued from the same initial mini-halo. However this imposes (i) the total virial mass to be smaller than 3x10^8Msol, (ii) the stellar content prior to the end of the re-ionisation epoch to be very compact (<15 pc) and strongly gravitationally bound, a challenge for current hydro-dynamical numerical simulations. If initial stellar building blocks are larger than 35 pc the size of the UFD will extend to 80 pc. Finally, our study shows that UFDs keep strong imprints of their build-up history in the form of elongated or extended stellar halos. Those features can erroneously be interpreted as tidal signatures.

13.Periodic changes in the morphology of the Galactic resonance rings

Authors:A. M. Melnik, E. N. Podzolkova, A. K. Dambis

Abstract: We study the periodic enhancement of either trailing or leading segments of the resonance elliptical rings in the dynamical model of the Galaxy which reproduces distributions of observed velocities derived from Gaia DR3 (EDR3) data along the Galactocentric distance. The model disc forms a nuclear ring, an inner combined ring and outer resonance rings R1 and R2. The backbone of the inner combined ring is banana-type orbits around the Lagrange equilibrium points L4 and L5. Orbits associated with the unstable equilibrium points L1 and L2 also support the inner ring. We have found the changes of the morphology of the inner ring with a period of P=0.57+/-0.02 Gyr, which is close to the period of revolution along the long-period orbits around the points L4 and L5. A possible explanation of these morphological changes is the formation of an overdensity which then begins circulating along the closed contour. In the region of the Outer Lindblad Resonance (OLR), we have found the changes of the morphology of the outer rings with a period of P=2.0+/-0.1 Gyr. Probably, the morphological changes of the outer rings are due to the orbits trapped by the OLR. These orbits exhibit librations of the direction of orbital elongation with respect to the minor axis of the bar as well as the long-term variations in the stellar angular momentum, energy, average radius of the orbit, and eccentricity. Among many librating orbits, we discovered orbits with the libration period of P=1.91+/-0.01 Gyr, which may cause the morphological changes of the outer rings.

14.Scalar-tensor-vector-gravity and NGC-1277

Authors:John W. Moffat, Viktor T. Toth

Abstract: NGC1277 is a compact but massive lenticular galaxy that shows no signs of the presence of dark matter. We find that this galaxy's behavior is consistent not only with Newtonian dynamics, but also with the predictions of Scalar--Tensor--Vector--Gravity, also known as MOG (MOdified Gravity). The compact size of the galaxy, in combination with its large mass, ensures that there are no observable deviations between the predictions of Newtonian and MOG orbital velocities within the galaxy's visible radius.

1.Analysis of the interstellar matter at the periphery of the supershell surrounding the CYG OB1 association in 2.12 micron molecular hydrogen line

Authors:D. S. Wiebe, T. G. Sitnik, A. S. Rastorguev, T. A. Lozinskaya, A. M. Tatarnikov, A. A. Tatarnikova, A. P. Topchieva, M. V. Zabolotskikh, A. A. Fedoteva, A. A. Tatarnikov

Abstract: We present observations of the vdB 130 cluster vicinity in a narrow-band filter centered at a $2.12\,\mu$m molecular hydrogen line performed at the Caucasus Mountain Observatory of the Lomonosov Moscow State University. The observations reveal an H$_2$ emission shell around vdB 130, coincident with a bright infrared shell, visible in all \textit{Spitzer} bands. Also, numerous H$_{2}$ emission features are detected around infrared Blobs E and W and in the vicinity of a protocluster located to the east of the shell, in a tail of a cometary molecular cloud. H$_2$ emission in the vicinity of the vdB~130 cluster is mostly generated in well-developed \HII\ regions and is of fluorescent nature. In the protocluster area, isolated spots are observed, where H$_2$ emission is collisionally excited and is probably related to shocks in protostellar outflows. Obtained results are discussed in the context of possible sequential star formation in the vicinity of the vdB 130 cluster, triggered by the interaction of the expanding supershell surrounding the Cyg OB1 association with the molecular cloud and an associated molecular filament.

2.Star formation characteristics of galaxies hosting AGN

Authors:Payel Nandi, C. S. Stalin

Abstract: We present an analysis of the ultra-violet (UV) observations of two Seyfert type active galactic nuclei (AGN), namely NGC$~$4051 and NGC$~$4151. These observations aimed at studying the star formation in the hosts of these AGN were carried out with the ultra-violet imaging telescope on board AstroSat in far-UV. A total of 193 and 328 star-forming regions (SF) were identified using SExtractor in NGC$~$4051 and NGC$~$4151, respectively. Using aperture photometry of the identified SF regions, we estimated the star formation rates (SFRs). We found NGC$~$4051 to have the lowest SFR with a median value of 3.16 $\times$ 10$^{-5}$ M$_{\odot}$ yr$^{-1}$ while for NGC$~$4151, we found a median SFR of 0.012 M$_{\odot}$ yr$^{-1}$.

3.The Lyman Continuum Escape Fraction of Star-forming Galaxies at $2.4\lesssim z\lesssim3.7$ from UVCANDELS

Authors:Xin Wang, Harry I. Teplitz, Brent M. Smith, Rogier A. Windhorst, Marc Rafelski, Vihang Mehta, Anahita Alavi, Gabriel Brammer, James Colbert, Norman Grogin, Nimish P. Hathi, Anton M. Koekemoer, Laura Prichard, Claudia Scarlata, Ben Sunnquist, Pablo Arrabal Haro, Christopher Conselice, Eric Gawiser, Yicheng Guo, Matthew Hayes, Rolf A. Jansen, Zhiyuan Ji, Ray A. Lucas, Robert O'Connell, Brant Robertson, Michael Rutkowski, Brian Siana, Eros Vanzella, Teresa Ashcraft, Micaela Bagley, Ivano Baronchelli, Guillermo Barro, Alex Blanche, Adam Broussard, Timothy Carleton, Nima Chartab, Yingjie Cheng, Alex Codoreanu, Seth Cohen, Y. Sophia Dai, Behnam Darvish, Romeel Dave, Laura DeGroot, Duilia De Mello, Mark Dickinson, Najmeh Emami, Henry Ferguson, Leonardo Ferreira, Keely Finkelstein, Steven Finkelstein, Jonathan P. Gardner, Timothy Gburek, Mauro Giavalisco, Andrea Grazian, Caryl Gronwall, Shoubaneh Hemmati, Justin Howell, Kartheik Iyer, Sugata Kaviraj, Peter Kurczynski, Ilin Lazar, John MacKenty, Kameswara Bharadwaj Mantha, Alec Martin, Garreth Martin, Tyler McCabe, Bahram Mobasher, Kalina Nedkova, Charlotte Olsen, Lillian Otteson, Swara Ravindranath, Caleb Redshaw, Zahra Sattari, Emmaris Soto, L. Y. Aaron Yung, Bonnabelle Zabelle, the UVCANDELS team

Abstract: The UltraViolet Imaging of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey Fields (UVCANDELS) survey is a Hubble Space Telescope (HST) Cycle-26 Treasury Program, allocated in total 164 orbits of primary Wide-Field Camera 3 Ultraviolet and Visible light F275W imaging with coordinated parallel Advanced Camera for Surveys F435W imaging, on four of the five premier extragalactic survey fields: GOODS-N, GOODS-S, EGS, and COSMOS. We introduce this survey by presenting a thorough search for galaxies at $z\gtrsim2.4$ that leak significant Lyman continuum (LyC) radiation, as well as a stringent constraint on the LyC escape fraction ($f_{\rm esc}$) from stacking the UV images of a population of star-forming galaxies with secure redshifts. Our extensive search for LyC emission and stacking analysis benefit from the catalogs of high-quality spectroscopic redshifts compiled from archival ground-based data and HST slitless spectroscopy, carefully vetted by dedicated visual inspection efforts. We report a sample of five galaxies as individual LyC leaker candidates, showing $f_{\rm esc}^{\rm rel}\gtrsim60\%$ estimated using detailed Monte Carlo analysis of intergalactic medium attenuation. We develop a robust stacking method to apply to five samples of in total 85 non-detection galaxies in the redshift range of $z\in[2.4,3.7]$. Most stacks give tight 2-$\sigma$ upper limits below $f_{\rm esc}^{\rm rel}<6\%$. A stack for a subset of 32 emission-line galaxies shows tentative LyC leakage detected at 2.9-$\sigma$, indicating $f_{\rm esc}^{\rm rel}=5.7\%$ at $z\sim2.65$, supporting the key role of such galaxies in contributing to the cosmic reionization and maintaining the UV ionization background. These new F275W and F435W imaging mosaics from UVCANDELS have been made publicly available on the Barbara A. Mikulski Archive for Space Telescopes.

4.The Structure and Morphology of Galaxies during the Epoch of Reionization Revealed by JWST

Authors:Wen Sun, Luis C. Ho, Ming-Yang Zhuang, Chao Ma, Changhao Chen, Ruancun Li

Abstract: We analyze 347 galaxies at redshift $4<z<9.5$ using JWST observations from the CEERS program by fitting a two-dimensional parametric model simultaneously to the seven-filter NIRCam images to measure the overall structural parameters and quantify the global properties of the galaxies in the rest-frame optical band. Particular attention is devoted to deriving robust uncertainties that include, among other factors, the influence of cosmological surface brightness dimming and resolution effects. Using the global S\'ersic index ($n < 1.5$) and observed axial ratio ($q < 0.6$) as a guide, we place a conservative lower limit of $\sim 45\%$ on the incidence of galactic disks. Galaxies follow a relation between rest-frame optical luminosity and effective radius in the redshift range $4<z<9.5$, as well as separately over the intervals $4 < z < 5$ and $5 \leq z < 9.5$, with a very similar slope but a marginally lower zero point in the higher redshift bin ($R_e = 0.49 \pm 0.07$ kpc) compared to the lower redshift bin ($R_e = 0.65 \pm 0.12$ kpc). Within the limitations of the current sample size, we find no significant redshift evolution of $n$ or $R_e$ at these early epochs.

5.The haloes and environments of nearby galaxies (HERON) -- III. A 45 kpc spiral structure in the GLSB galaxy UGC 4599

Authors:Aleksandr V. Mosenkov, R. Michael Rich, Michael Fusco, Julia Kennefick, David Thilker, Alexander Marchuk, Noah Brosch, Michael West, Michael Gregg, Francis Longstaff, Andreas J. Koch-Hansen, Shameer Abdeen, William Roque

Abstract: We use a 0.7-m telescope in the framework of the Halos and Environments of Nearby Galaxies (HERON) survey to probe low surface brightness structures in nearby galaxies. One of our targets, UGC 4599, is usually classified as an early-type galaxy surrounded by a blue ring making it a potential Hoag's Object analog. Prior photometric studies of UGC 4599 were focused on its bright core and the blue ring. However, the HERON survey allows us to study its faint extended regions. With an eight hour integration, we detect an extremely faint outer disk with an extrapolated central surface brightness of $\mu_\mathrm{0,d}(r)=25.5$ mag arcsec$^{-2}$ down to 31 mag arcsec$^{-2}$ and a scale length of 15 kpc. We identify two distinct spiral arms of pitch angle ~6{\deg} surrounding the ring. The spiral arms are detected out to ~45 kpc in radius and the faint disk continues to ~70 kpc. These features are also seen in the GALEX FUV and NUV bands, in a deep u-band image from the 4.3m Lowell Discovery Telescope (which reveals inner spiral structure emerging from the core), and in HI. We compare this galaxy to ordinary spiral and elliptical galaxies, giant low surface brightness (GLSB) galaxies, and Hoag's Object itself using several standard galaxy scaling relations. We conclude that the pseudobulge and disk properties of UGC 4599 significantly differ from those of Hoag's Object and of normal galaxies, pointing toward a GLSB galaxy nature and filamentary accretion of gas to generate its outer disk.

6.Stellar/BH Population in AGN Disks: Direct Binary Formation from Capture Objects in Nuclei Clusters

Authors:Yihan Wang, Zhaohuan Zhu, Douglas N. C. Lin

Abstract: The Active Galatic Nuclei(AGN) disk has been proposed as a potential channel for the merger of binary black holes. The population of massive stars and black holes in AGN disks captured from the nuclei cluster plays a crucial role in determining the efficiency of binary formation and final merger rate within the AGN disks. In this paper, we investigate the capture process using analytical and numerical approaches. We discover a new constant integral of motion for one object's capture process. {Applying this result to the whole population of the nuclei cluster captured by the AGN disk, we find that the population of captured objects} depends on the angular density and eccentricity distribution of the nuclei clusters and is effectively independent of the radial density profile of the nuclei cluster and disk models. An isotropic nuclei cluster with thermal eccentricity distribution predicts a captured profile $\dd N/\dd r\propto r^{-1/4}$. The captured objects are found to be dynamically crowded within the disk. Direct binary formation right after the capture would be promising, especially for stars. The conventional migration traps that help pile up single objects in AGN disks for black hole mergers might not be required.

7.Dark Matter reconstruction from stellar orbits in the Galactic Centre

Authors:Thibault Lechien, Gernot Heißel, Jai Grover, Dario Izzo

Abstract: Context. Current constraints on distributed matter in the innermost Galactic Centre (such as a cluster of faint stars and stellar remnants, Dark Matter or a combination thereof) based on the orbital dynamics of the visible stars closest to the central black hole, typically assume simple functional forms for the distributions. Aims. We take instead a general model agnostic approach in which the form of the distribution is not constrained by prior assumptions on the physical composition of the matter. This approach yields unbiased - entirely observation driven - fits for the matter distribution and places constraints on our ability to discriminate between different density profiles (and consequently between physical compositions) of the distributed matter. Methods. We construct a spherical shell model with the flexibility to fit a wide variety of physically reasonable density profiles by modelling the distribution as a series of concentric mass shells. We test this approach in an analysis of mock observations of the star S2. Results. For a sufficiently large and precise data set, we find that it is possible to discriminate between several physically motivated density profiles. However, for data coming from current and expected next generation observational instruments, the potential for profile distinction will remain limited by the precision of the instruments. Future observations will still be able to constrain the overall enclosed distributed mass within the apocentre of the probing orbit in an unbiased manner. We interpret this in the theoretical context of constraining the secular versus non-secular orbital dynamics.

1.Deriving physical parameters of unresolved star clusters. VII. Adaptive aperture photometry of the M31 PHAT star clusters

Authors:Eimantas Krisciunas Center for Physical Sciences and Technology, Vilnius, Lithuania, Karolis Daugevicius Center for Physical Sciences and Technology, Vilnius, Lithuania, Rima Stonkute Center for Physical Sciences and Technology, Vilnius, Lithuania, Vladas Vansevicius Center for Physical Sciences and Technology, Vilnius, Lithuania

Abstract: This work is the seventh study in a series dedicated to investigating degeneracies of simultaneous age, mass, extinction, and metallicity determinations of partially resolved or unresolved star clusters with Hubble Space Telescope broadband aperture photometry. In the sixth work (hereafter, Paper I), it was demonstrated that the adaptive aperture photometry, performed to avoid the majority of the projected foreground and background stars falling within the apertures, gives more consistent colour indices for star clusters. In this study, we aim to supplement the homogeneous multi-colour aperture photometry results published in Paper~I and provide a complete M31 Panchromatic Hubble Andromeda Treasury (PHAT) survey star cluster photometry catalogue for further analysis. Following Paper I, we used a two-aperture approach for photometry. The first aperture is the standard one used to measure total cluster fluxes. The second (smaller) aperture is introduced to avoid the bright foreground and background stars projecting onto the clusters. We selected the radii of smaller apertures to be larger than the half-light radii of the clusters. We present the second part of the star cluster aperture photometry catalogues for a sample of 1477 star clusters from the M31 PHAT survey not covered in Paper I. Compared to the M31 PHAT star cluster aperture photometry catalogue published by Johnson et al., adjustments were made to the cluster centre coordinates, aperture sizes, and sky background levels.

2.Galaxy Rotation Curve Fitting Using Machine Learning Tools

Authors:Carlos R. Argüelles, Santiago Collazo

Abstract: Galaxy rotation curve (RC) fitting is an important technique which allows the placement of constraints on different kinds of dark matter (DM) halo models. In the case of non-phenomenological DM profiles with no analytic expressions, the art of finding RC best-fits including the full baryonic $+$ DM free parameters can be difficult and time-consuming. In the present work, we use a gradient descent method used in the backpropagation process of training a neural network, to fit the so-called Grand Rotation Curve of the Milky Way (MW) ranging from $\sim$1 pc all the way to $\sim$$10^5$ pc. We model the mass distribution of our Galaxy including a bulge (inner $+$ main), a disk, and a fermionic dark matter (DM) halo known as the Ruffini-Arg\"uelles-Rueda (RAR) model. This is a semi-analytical model built from first-principle physics such as (quantum) statistical mechanics and thermodynamics, whose more general density profile has a dense core -- diluted halo morphology with no analytic expression. As shown recently and further verified here, the dark and compact fermion-core can work as an alternative to the central black hole in SgrA* when including data at milliparsec scales from the S-cluster stars. Thus, we show the ability of this state-of-the-art machine learning tool in providing the best-fit parameters to the overall MW RC in the $10^{-2}$--$10^5$ pc range, in a few hours of CPU time.

3.Galactic Archaeology: Tracing the Milky Way's Formation and Evolution through Stellar Populations

Authors:J. Alfredo Collazos

Abstract: Galactic archaeology represents a multidisciplinary approach aimed at unraveling the intricate history of the Milky Way galaxy through the study of its stellar populations. This abstract delves into the significance of galactic archaeology as a vital tool for understanding the formation and evolution of the Milky Way. By examining the distribution, kinematics, chemical compositions, and ages of stars within the galaxy, researchers gain insights into the dynamic processes that have shaped its structure over billions of years. Stellar populations serve as invaluable relics of past epochs, preserving clues about the conditions prevalent during their formation. The utilization of spectroscopic and photometric data has enabled the classification and analysis of stars, allowing astronomers to discern distinct populations and unveil their origin stories. Through these studies, the emergence of the Milky Way's various components, such as the thin and thick disk, halo, and bulge, becomes discernible.

4.Survey of Bare Active Galactic Nuclei in the local universe (z < 0.2): I. On the origin of Soft-Excess

Authors:Prantik Nandi, Arka Chatterjee, Arghajit Jana, Sandip K. Chakrabarti, Sachindra Naik, Samar Safi-Harb, Hsiang-Kuang Chang, Jeremy Heyl

Abstract: We analyse a sample of 21 `bare' Seyfert~1 Active Galactic Nuclei (AGNs), a sub-class of Seyfert~1s, with intrinsic absorption $\mathrm{N_{H}} \sim 10^{20}~ \mathrm{cm}^{-2}$, in the local universe (z $<$ 0.2) using {\it XMM-Newton} and {\it Swift}/XRT observations. The luminosities of the primary continuum, the X-ray emission in the 3 to 10 keV energy range and the soft-excess, the excess emission that appears above the low-energy extrapolation of the power-law fit of 3 to 10 keV X-ray spectra, are calculated. Our spectral analysis reveals that the long-term intrinsic luminosities of the soft-excess and the primary continuum are tightly correlated $(L_{PC}\propto L_{SE}^{1.1\pm0.04})$. We also found that the luminosities are correlated for each source. This result suggests that both the primary continuum and soft excess emissions exhibit a dependency on the accretion rate in a similar way.

5.First spectroscopic observations of the galaxies that reionized the Universe

Authors:Hakim Atek, Ivo Labbé, Lukas J. Furtak, Iryna Chemerynska, Seiji Fujimoto, David J. Setton, Tim B. Miller, Pascal Oesch, Rachel Bezanson, Sedona H. Price, Pratika Dayal, Adi Zitrin, Vasily Kokorev, John R. Weaver, Gabriel Brammer, Pieter van Dokkum, Christina C. Williams, Sam E. Cutler, Robert Feldmann, Yoshinobu Fudamoto, Jenny E. Greene, Joel Leja, Michael V. Maseda, Adam Muzzin, Richard Pan, Casey Papovich, Erica J. Nelson, Themiya Nanayakkara, Daniel P. Stark, Mauro Stefanon, Katherine A. Suess, Bingjie Wang, Katherine E. Whitaker

Abstract: High-redshift low-mass galaxies are believed to be the building blocks of present-day galaxies. Their sheer prevalence, compared to their more massive counterparts, makes them the most representative examples of the first generation of galaxies. Furthermore, they likely played a pivotal role in cosmic reionization between redshifts of $z=9$ and $z=6$. However, this population has continued to elude comprehensive spectroscopic studies. As a consequence, their role in comic reionization has remained unclear, owing to the uncertainties surrounding their photometric redshifts and the lack of constraints on both their ionizing photon production and escape fraction. Here we report the first spectroscopic analysis of 8 ultra-faint galaxies during the epoch of reionization with absolute magnitudes between M$_{\rm UV} \sim -17$ to $-15$ mag (down to 0.005 $L^{\star}$). The combination of ultra-deep NIRSpec (Near-Infrared Spectrograph) observations and the strong gravitational lensing of Abell~2744 allows us to explore an uncharted territory of early galaxy formation. Remarkably, some of these galaxies have stellar masses as low as $7.6_{-1.4}^{+1.7} \times 10^{5}$ \msol, comparable to dwarf galaxies in the local group, and extremely low metallicities of only 1 to 6\% $Z_{\odot}$. This sample allows us to derive the first combined spectroscopic constraints on both the prevalence of faint galaxies and their ionizing properties during the Universe's first billion years. We find that faint galaxies have an ionizing efficiency of log($\xi_{\rm ion}$/ Hz erg$^{-1}$)=$25.8\pm 0.05$, about a factor of 4 larger than canonical values. This means that the total ionizing photon budget produced by galaxies exceeds the reionization threshold, even for modest values of $f_{\rm esc}$ =5%. These findings provide robust evidence that faint galaxies were the main drivers of cosmic reionization at $z\sim7$.

1.Massive black hole binaries as sources of low-frequency gravitational waves and X-shape radio galaxies

Authors:Małgorzata Curyło, Tomasz Bulik

Abstract: We present the study of multi-messenger signatures of massive black hole (MBH) binaries residing in the centres of galaxy merger remnants. In particular, we first focus on the gravitational wave background (GWB) produced by an ensemble of MBH binary inspirals in the frequency range probed by the Pulsar Timing Array (PTA) experiments. The improved estimates of the characteristic strain were obtained with the inclusion of environmental effects on the MBH binary orbital decay within the galaxy merger remnants, added in post-processing to the semi-analytic model of galaxy formation and evolution SHARK. Secondly, we explore two, intriguing in terms of the MBH binary evolution studies, hypotheses aiming to explain the origins of X-shape radio galaxies - a peculiar type of objects with double lobe structures, constituting approximately 6 - 10% of known radio loud galaxies. The two considered scenarios involve either an abrupt change in the jet direction after a MBH merger (a spin-flip) or an unresolved close binary, where each of the two components produces a jet. We find that the estimated GWB amplitude at the reference frequency $f_0=1 \,{\rm yr}^{-1}$ is in the range of $A_{\rm{ yr^{-1}}} = 1.29\cdot10^{-15} - 1.46\cdot10^{-15}$, which is 50% lower than the strain of the signal detected by the PTA experiments. We also show that the spin-flip scenario considered in gas-poor mergers reproduces the observed properties of X-shape radio galaxies well in terms of flip angle, redshift and luminosity distributions.

1.A search for high-redshift direct collapse black hole candidates in the PEARLS north ecliptic pole field

Authors:Armin Nabizadeh, Erik Zackrisson, Fabio Pacucci, Peter W. Maksym, Weihui Li, Francesca Civano, Seth H. Cohen, Jordan C. J. D'Silva, Anton M. Koekemoer, Jake Summers, Rogier A. Windhorst, Nathan Adams, Christopher J. Conselice, Dan Coe, Simon P. Driver, Brenda Frye, Norman A. Grogin, Rolf A. Jansen, Madeline A. Marshall, Mario Nonino, Nor Pirzkal, Aaron Robotham, Michael J. Rutkowski, Russell E. Ryan, Jr., Scott Tompkins, Christopher N. A. Willmer, Haojing Yan, Jose M. Diego, Cheng Cheng, Steven L. Finkelstein, S. P. Willner, Adi Zitrin, Rachana Bhatawdekar, Hansung B. Gim

Abstract: Direct-collapse black holes (DCBHs) of mass $\sim 10^4$-$10^5 M_\odot$ that form in HI-cooling halos in the early Universe are promising progenitors of the $\gtrsim 10^9 M_\odot$ supermassive black holes that fuel the observed $z \gtrsim 7$ quasars. Efficient accretion of the surrounding gas onto such DCBH seeds may render them sufficiently bright for detection with the James Webb Space Telescope (JWST) up to $z\approx 15$. Additionally, the very steep and red spectral slope predicted across the $\approx 1$-5 $\mu$m wavelength range of the JWST/NIRSpec instrument during their initial growth phase should make them photometrically identifiable up to very high redshifts. Here, we present a search for such DCBH candidates across the 34 arcmin$^{2}$ in the first two spokes of the JWST cycle-1 "Prime Extragalactic Areas for Reionization and Lensing Science" (PEARLS) survey of the North Ecliptic Pole Time Domain Field (NEP), covering 8 NIRCam filters down to a maximum depth of $\sim$ 29 AB mag. We identify three objects with spectral energy distributions consistent with the Pacucci et al. (2016) DCBH models. However, we also note that even with data in 8 NIRCam filters, objects of this type remain degenerate with dusty galaxies and obscured active galactic nuclei over a wide range of redshifts. Follow-up spectroscopy would be required to pin down the nature of these objects, and two of our DCBH candidates are sufficiently bright to make this practical. Based on our sample of DCBH candidates and assumptions on the typical duration of the DCBH steep-slope state, we set a conservative upper limit of $\approx 7\times 10^{-4}$ comoving Mpc$^{-3}$ (cMpc$^{-3}$) on the comoving density of host halos capable of hosting DCBHs with spectral energy distributions similar to the Pacucci et al. (2016) models at $z\approx 6$-13.

1.Galactic Interstellar Scintillation Observed from Four Globular Cluster Pulsars by FAST

Authors:Dandan Zhang, Zhenzhao Tao, Mao Yuan, Jumei Yao, Pei Wang, Qijun Zhi, Weiwei Zhu, Xun Shi, Michael Kramer, Di Li, Lei Zhang, Guangxing Li

Abstract: We report detections of scintillation arcs for pulsars in globular clusters M5, M13 and M15 for the first time using the Five-hundred-meter Aperture Spherical radio Telescope (FAST). From observations of these arcs at multiple epochs, we infer that screen-like scattering medium exists at distances $4.1_{-0.3}^{+0.2}$ kpc, $6.7_{-0.2}^{+0.2}$ kpc and $1.3_{-1.0}^{+0.7}$ kpc from Earth in the directions of M5, M13 and M15, respectively. This means M5's and M13's scattering screens are located at $3.0_{-0.2}^{+0.1}$ kpc and $4.4_{-0.1}^{+0.1}$ kpc above the galactic plane, whereas, M15's is at $0.6_{-0.5}^{+0.3}$ kpc below the plane. We estimate the scintillation timescale and decorrelation bandwidth for each pulsar at each epoch using the one-dimensional auto-correlation in frequency and time of the dynamic spectra. We found that the boundary of the Local Bubble may have caused the scattering of M15, and detected the most distant off-plane scattering screens to date through pulsar scintillation, which provides evidence for understanding the medium circulation in the Milky Way.

2.Optical and near-UV spectroscopic properties of low-redshift jetted quasars in the main sequence context

Authors:Shimeles Terefe, Ascensión Del Olmo, Paola Marziani, Mirjana Pović, María Angeles Martínez-Carballo, Jaime Perea, Isabel Márquez

Abstract: This paper presents new optical and near-UV spectra of 11 extremely powerful jetted quasars, with radio to optical flux density ratio $>$ 10$^3$, that concomitantly cover the low-ionization emission of \mgii\ and \hb\ as well as the \feii\ blends in the redshift range $0.35 \lesssim z \lesssim 1$. We aim to quantify broad emission line differences between radio-loud (RL) and radio-quiet (RQ) quasars by using the 4D eigenvector 1 parameter space and its Main Sequence (MS) and to check the effect of powerful radio ejection on the low ionization broad emission lines. The \hb\ and \mgii\ emission lines were measured by using non-linear multicomponent fittings as well as by analysing their full profile. We found that broad emission lines show large redward asymmetry both in \hb\ and \mgii. The location of our RL sources in a UV plane looks similar to the optical one, with weak \feiiuv\ emission and broad \mgii. We supplement the 11 sources with large samples from previous work to gain some general inferences. We found that, compared to RQ, our extreme RL quasars show larger median \hb\ full width at half maximum (FWHM), weaker \feii\ emission, larger \mbh, lower \lledd, and a restricted bf space occupation in the optical and UV MS planes. The differences are more elusive when the comparison is carried out by restricting the RQ population to the region of the MS occupied by RL sources, albeit an unbiased comparison matching \mbh\ and \lledd\ suggests that the most powerful RL quasars show the highest redward asymmetries in \hb.

3.A peculiar galaxy near M104

Authors:E. Quiroga

Abstract: Messier 104, NGC 4594, also known as the Sombrero Galaxy, has been extensively studied, especially its structure and stellar halo. Its abundance of globular clusters has given rise to many theories and much speculation (Ford H. C. et al 1996). But other objects in the vicinity of such a spectacular galaxy are sometimes ignored. While studying HST images available on the HST Legacy website of the halo of M104 (HST proposal 9714, PI: Keith Noll), the author observed at 12:40:07.829 -11:36:47.38 (in j2000) an object about 4 arcseconds in diameter. A study with VO tools suggests that the object is a SBc galaxy with AGN (Seyfert).

4.Hot Stellar Populations of Berkeley 39 using Swift/UVOT

Authors:Komal Chand Department of Physics, Birla Institute of Technology and Science-Pilani, 333031 Rajasthan, India, Khushboo Kunwar Rao Department of Physics, Birla Institute of Technology and Science-Pilani, 333031 Rajasthan, India, Kaushar Vaidya Department of Physics, Birla Institute of Technology and Science-Pilani, 333031 Rajasthan, India, Anju Panthi Department of Physics, Birla Institute of Technology and Science-Pilani, 333031 Rajasthan, India

Abstract: Open clusters are excellent tools to probe the history of the Galactic disk and properties of star formation. In this work, we present a study of an old age open cluster Berkley 39 using the observations from UVOT instrument of the Neil Gehrels Swift observatory. Making use of a machine learning algorithm, ML-MOC, we have identified a total of 861 stars as cluster members out of which 17 are blue straggler stars. In this work, we present a characterisation of 2 blue straggler stars. To estimate the fundamental parameters of blue straggler stars and their companions (if any), we constructed spectral energy distributions using UV data from swift/UVOT and GALEX, optical data from Gaia DR3, and infrared (IR) data from 2MASS, Spitzer/IRAC, and WISE. We find excess flux in UV in one blue straggler star, implying the possibility of a hot companion.

1.The Automated Reaction-Pathway Search reveals the Energetically Favorable Synthesis of Interstellar CH3OCH3 and HCOOCH3

Authors:Yu Komatsu, Kenji Furuya

Abstract: Recent astronomical observations have shown that interstellar complex organic molecules (COMs) exist even in cold environments ($\sim$10 K), while various interstellar COMs have conventionally been detected in the hot gas ($\gtrsim$ 100 K) in the vicinity of high-mass and low-mass protostars. However, the formation pathway of each interstellar COM remains largely unclear. In this work, we demonstrate that an automated reaction path search based on transition state theory, which does not require predetermined pathways, is helpful for investigating the formation pathways of interstellar COMs in the gas phase. The exhaustive search within electronic ground states helps elucidate the complex chemical formation pathways of COMs at low temperatures. Here we examine the formation pathways of dimethyl ether (CH$_3$OCH$_3$) and methyl formate (HCOOCH$_3$), which are often detected in the cold and hot gas of star-forming regions. We have identified a barrierless and exothermic formation path of CH$_3$OCH$_3$ by reaction between neutral species; CH$_3$O + CH$_3$ $\rightarrow$ H$_2$CO $\cdots$ CH$_4$ $\rightarrow$ CH$_3$OCH$_3$ is the most efficient path in the large chemical network constructed by our automated reaction path search and is comparable with previous studies. For HCOOCH$_3$, we obtain complex pathways initiated from reactions between neutral species; HCOO and CH$_3$ generate HCOOCH$_3$ and its isomers without external energy. However, we also identified the competing reaction branches producing CO$_2$ + CH$_4$ and CH$_3$COOH, which would be more efficient than the formation of HCOOCH$_3$. Then the gas-phase formation of HCOOCH$_3$ through reactions between neutral species would not be efficient compared to the CH3OCH$_3$ formation.

1.The Accretion Mode in Sub-Eddington Supermassive Black Holes: Getting into the Central Parsecs of Andromeda

Authors:C. Alig, A. Prieto, M. Blaña, M. Frischman, C. Metzl, A. Burkert, O. Zier, A. Streblyanska

Abstract: The inner kiloparsec regions surrounding sub-Eddington (luminosity less than 10$^{-3}$ in Eddington units, L$_{Edd}$) supermassive black holes (BHs) often show a characteristic network of dust filaments that terminate in a nuclear spiral in the central parsecs. Here we study the role and fate of these filaments in one of the least accreting BHs known, M31 (10$^{-7}$ L$_{Edd}$) using hydrodynamical simulations. The evolution of a streamer of gas particles moving under the barred potential of M31 is followed from kiloparsec distance to the central parsecs. After an exploratory study of initial conditions, a compelling fit to the observed dust/ionized gas morphologies and line-of-sight velocities in the inner hundreds of parsecs is produced. After several million years of streamer evolution, during which friction, thermal dissipation, and self-collisions have taken place, the gas settles into a disk tens of parsecs wide. This is fed by numerous filaments that arise from an outer circumnuclear ring and spiral toward the center. The final configuration is tightly constrained by a critical input mass in the streamer of several 10$^3$ M$_{\odot}$ (at an injection rate of 10$^{-4}$ M$_{\odot}$ yr$^{-1}$); values above or below this lead to filament fragmentation or dispersion respectively, which are not observed. The creation of a hot gas atmosphere in the region of $\sim$10$^6$ K is key to the development of a nuclear spiral during the simulation. The final inflow rate at 1pc from the center is $\sim$1.7 $\times$ 10$^{-7}$ M$_{\odot}$ yr$^{-1}$, consistent with the quiescent state of the M31 BH.

2.Statistical analysis of kicked black holes from TNG300 simulation

Authors:Majda Smole, Miroslav Micic

Abstract: Asymmetric emission of gravitational waves during mergers of black holes (BHs) produces a recoil kick, which can set a newly formed BH on a bound orbit around the center of its host galaxy, or even completely eject it. To study this population of recoiling BHs we extract properties of galaxies with merging BHs from Illustris TNG300 simulation and then employ both analytical and numerical techniques to model unresolved process of BH recoil. This comparative analysis between analytical and numerical models shows that, on cosmological scales, numerically modeled recoiling BHs have a higher escape probability and predict a greater number of offset active galactic nuclei (AGN). BH escaped probability $>40~ \%$ is expected in 25 $\%$ of merger remnants in numerical models, compared to 8$\%$ in analytical models. At the same time, the predicted number of offset AGN at separations $>5$ kpc changes from 58 $\%$ for numerical models to 3 $\%$ for analytical models. Since BH ejections in major merger remnants occur in non-virialized systems, static analytical models cannot provide an accurate description. Thus we argue that numerical models should be used to estimate the expected number density of escaped BHs and offset AGN.

3.Constraining Supernova Ia Progenitors by their Locations in Host Galactic Disc

Authors:A. A. Hakobyan, A. G. Karapetyan, L. V. Barkhudaryan

Abstract: Among the diverse progenitor channels leading to Type Ia Supernovae (SNe Ia), there are explosions originating from white dwarfs with sub-Chandrasekhar masses. These white dwarfs undergo detonation and explosion triggered by primary detonation in the helium shell, which has been accreted from a companion star. The double-detonation model predicts a correlation between the age of the progenitor system and the near peak brightness: the younger the exploding progenitors, the brighter the SNe. In this paper, we present our recent achievements on the study of SNe Ia properties in different locations within host galactic discs and the estimation of their progenitor population ages. Observationally, we confirm the validity of the anticipated correlation between the SN photometry and the age of their progenitors.

4.Enhanced Sub-kpc Scale Star-formation: Results From A JWST Size Analysis of 339 Galaxies At 5<z<14

Authors:Takahiro Morishita, Massimo Stiavelli, Ranga-Ram Chary, Michele Trenti, Pietro Bergamini, Marco Chiaberge, Nicha Leethochawalit, Guido Roberts-Borsani, Xuejian Shen, Tommaso Treu

Abstract: We present a comprehensive search and analysis of high-redshift galaxies in a suite of nine public JWST extragalactic fields taken in Cycle 1, covering a total effective search area of $\sim358{\rm arcmin^2}$. Through conservative ($8\sigma$) photometric selection, we identify 339 galaxies at $5<z<14$, with 109 having spectroscopic redshift measurements from the literature, including recent JWST NIRSpec observations. Our regression analysis reveals that the rest-frame UV size-stellar mass relation follows $R_{\rm eff}\propto M_*^{0.20\pm0.03}$, similar to that of star-forming galaxies at $z\sim3$, but scaled down in size by $\sim0.7$dex. We find a much slower rate for the average size evolution over the redshift range, $R_{\rm eff}\propto(1+z)^{-0.4\pm0.2}$, than that derived in the literature. A fraction ($\sim13\,\%$) of our sample are marginally resolved even in the NIRCam imaging ($<100$pc), located at $>1.5\,\sigma$ below the derived size-mass slope. These compact sources exhibit a high star formation surface density $\Sigma_{\rm SFR}>10\,M_\odot\,{\rm yr^{-1}\,kpc^{-2}}$, a range in which only $<0.01\,\%$ of the local star-forming galaxy sample is found. For those with available NIRSpec data, no evidence of ongoing supermassive black hole accretion is observed. A potential explanation for the observed high [OIII]-to-Hbeta ratios could be high shock velocities, likely originating within intense star-forming regions characterized by high $\Sigma_{\rm SFR}$. Lastly, we find that the rest-frame UV and optical sizes of our sample are comparable. Our results are consistent with these early galaxies building up their structures inside-out and yet to exhibit the strong color gradient seen at lower redshift.

5.The contribution of faint Lyman-$α$ emitters to extended Lyman-$α$ halos constrained by MUSE clustering measurements

Authors:Yohana Herrero Alonso, L. Wisotzki, T. Miyaji, J. Schaye, J. Pharo, M. Krumpe

Abstract: Detections of extended Ly$\alpha$ halos (LAHs) around Ly$\alpha$ emitters (LAEs) have lately been reported on a regular basis, but their origin is still under investigation. Simulation studies predict that the outer regions of the extended LAHs contain a major contribution from the Ly$\alpha$ emission of faint, individually undetected LAEs. To address this matter from an observational angle, we use halo occupation distribution (HOD) modeling to reproduce the clustering of a spectroscopic sample of 1265 LAEs at $3<z<5$ from the MUSE-Wide survey. We integrate the Ly$\alpha$ luminosity function (LF) to estimate the background surface brightness due to discrete faint LAEs. We then extend the HOD statistics inwards towards small separations and compute the factor by which the measured Ly$\alpha$ surface brightness (SB) is enhanced by undetected close physical neighbors. We consider various clustering scenarios for the undetected sources and compare the corresponding radial profiles. The resulting inferred Ly$\alpha$ SB of faint LAEs ranges between $(0.4-2)\times10^{20}\;\rm{erg}\;\rm{s}^{-1}~\rm{cm}^{-2}~\rm{arcsec}^{-2}$, with a very slow radial decline outwards. Our results suggest that the outer regions of observed LAHs ($R\gtrsim50$~pkpc) could indeed contain a strong component from external (but physically associated) LAEs, possibly even be dominated by them. Only for a relatively shallow faint-end slope of the Ly$\alpha$ LF would this contribution from clustered LAEs become unimportant. We also confirm that the observed emission from the inner regions ($R\le20-30$~pkpc) is too bright to be significantly affected by clustering. We compare our findings with predicted profiles from simulations and find good overall agreement. We outline possible future measurements to further constrain the impact of discrete undetected LAEs on observed extended LAHs.

6.FLORAH: A generative model for halo assembly histories

Authors:Tri Nguyen, Chirag Modi, L. Y. Aaron Yung, Rachel S. Somerville

Abstract: The mass assembly history (MAH) of dark matter halos plays a crucial role in shaping the formation and evolution of galaxies. MAHs are used extensively in semi-analytic and empirical models of galaxy formation, yet current analytic methods to generate them are inaccurate and unable to capture their relationship with the halo internal structure and large-scale environment. This paper introduces FLORAH, a machine-learning framework for generating assembly histories of ensembles of dark matter halos. We train FLORAH on the assembly histories from the GUREFT and VSMDPL N-body simulations and demonstrate its ability to recover key properties such as the time evolution of mass and concentration. We obtain similar results for the galaxy stellar mass versus halo mass relation and its residuals when we run the Santa Cruz semi-analytic model on FLORAH-generated assembly histories and halo formation histories extracted from an N-body simulation. We further show that FLORAH also reproduces the dependence of clustering on properties other than mass (assembly bias), which is not captured by other analytic methods. By combining multiple networks trained on a suite of simulations with different redshift ranges and mass resolutions, we are able to construct accurate main progenitor branches (MPBs) with a wide dynamic mass range from $z = 0$ up to an ultra-high redshift $z \approx 20$, currently far beyond that of a single N-body simulation. FLORAH is the first step towards a machine learning-based framework for planting full merger trees; this will enable the exploration of different galaxy formation scenarios with great computational efficiency at unprecedented accuracy.

7.WISDOM Project -- XVII. Beam-by-beam Properties of the Molecular Gas in Early-type Galaxies

Authors:Thomas G. Williams, Martin Bureau, Timothy A. Davis, Michele Cappellari, Woorak Choi, Jacob S. Elford, Satoru Iguchi, Jindra Gensior, Fu-Heng Liang, Anan Lu, Ilaria Ruffa, Hengyue Zhang

Abstract: We present a study of the molecular gas of seven early-type galaxies with high angular resolution data obtained as part of the mm-Wave Interferometric Survey of Dark Object Masses (WISDOM) project with the Atacama Large Millimeter/submillimeter Array. Using a fixed spatial scale approach, we study the mass surface density ($\Sigma$) and velocity dispersion ($\sigma$) of the molecular gas on spatial scales ranging from $60$ to $120$pc. Given the spatial resolution of our data ($20$ - $70$pc), we characterise these properties across many thousands of individual sight lines ($\approx50,000$ at our highest physical resolution). The molecular gas along these sight lines has a large range ($\approx2$dex) of mass surface densities and velocity dispersions $\approx40\%$ higher than those of star-forming spiral galaxies. It has virial parameters $\alpha_\mathrm{vir}$ that depend weakly on the physical scale observed, likely due to beam smearing of the bulk galactic rotation, and is generally super-virial. Comparing the internal turbulent pressure ($P_\mathrm{turb}$) to the pressure required for dynamic equilibrium ($P_\mathrm{DE}$), the ratio $P_\mathrm{turb}$/$P_\mathrm{DE}$ is significantly less than unity in all galaxies, indicating that the gas is not in dynamic equilibrium and is strongly compressed, in apparent contradiction to the virial parameters. This may be due to our neglect of shear and tidal forces, and/or the combination of three-dimensional and vertical diagnostics. Both $\alpha_\mathrm{vir}$ and $P_\mathrm{turb}$ anti-correlate with the global star-formation rate of our galaxies. We therefore conclude that the molecular gas in early-type galaxies is likely unbound, and that large-scale dynamics likely plays a critical role in its regulation. This contrasts to the giant molecular clouds in the discs of late-type galaxies, that are much closer to dynamical equilibrium.

8.Discovery of a Split Stellar Stream In the Periphery of the Small Magellanic Cloud

Authors:David L. Nidever

Abstract: I report the discovery of a stellar stream (Sutlej) using Gaia DR3 proper motions and XP metallicities located ~15 degrees north of the Small Magellanic Cloud (SMC). The stream is composed of two parallel linear components ("branches") approximately ~8 x 0.6 degrees in size and separated by 2.5 degrees. The stars have a mean proper motion of (pmra,pmdec)=(+0.08 mas/yr,-1.41 mas/yr) which is quite similar to the proper motion of stars on the western side of the SMC. The color magnitude diagram of the stream stars has a clear red giant branch, horizontal branch, and main sequence turnoff that is well-matched by a PARSEC isochrone of 10 Gyr, [Fe/H]=-1.8 at 32 kpc and a total stellar mass of ~33,000 Msun. The stream is spread out over an area of 9.6 square degrees and has a surface brightness of 32.5 mag/arcsec^2. The metallicity of the stream stars from Gaia XP spectra extend over -2.5 < [M/H] < -1.0 with a median of [M/H]=-1.8. The tangential velocity of the stream stars is 214 km/s compared to the values of 448 km/s for the Large Magellanic Cloud and 428 km/s for the SMC. While the radial velocity of the stream is not yet known, a comparison of the space velocities using a range of assumed radial velocities, shows that the stream is unlikely to be associated with the Magellanic Clouds. The tangential velocity vector is misaligned with the stream by ~25 degrees which might indicate an important gravitational influence from the nearby Magellanic Clouds.

9.The missing quasar image in the gravitationally lensed quasar HE0230$-$2130: implications on dark satellites and the cored lens mass distribution

Authors:S. Ertl, S. Schuldt, S. H. Suyu, P. L. Schechter, A. Halkola, J. Wagner

Abstract: The quasar HE0230$-$2130 is lensed by two galaxies at similar redshifts into four observed images. Using modeled quasar positions from fitting the brightness of the quasar images in ground-based imaging data from the Magellan telescope, we find that lens mass models where both galaxies are each parametrized with a singular power-law (PL) profile predict five quasar images. One of the predicted images is unobserved even though it is distinctively offset from the lensing galaxies and is bright enough to be observable. This missing image gives rise to new opportunities to study the galaxies' mass distribution. To interpret the quad configuration of this system, we test different profile assumption with the aim to obtain lens mass models that predicts correctly only four observed images. We test the effect of adopting cored profiles for the lensing galaxies, of external shear, and of additional profiles to represent a dark matter clump. By comparing the Bayesian evidence of different model parametrizations, we favor the model class that consists of two singular PL profiles for the lensing galaxies and a cored isothermal sphere in the region of the previously predicted fifth images (rNIS profile). We estimate the mass of the rNIS clumps inside its Einstein radius and find that 18\% are in the range $10^6 M_{\odot} \leq M_{\rm rNIS}\leq 10^9 M_{\odot}$, which is the predicted mass range of dark matter subhalos in cold dark matter simulations, or the mass of low-mass dark matter satellite galaxies. The second most likely model class, with a relative probability of 94\%, is the model where the smaller lensing galaxy is described by a cored PL profile with external shear. Our study demonstrates that lensed quasar images are sensitive to dark matter structure in the gravitational lens.

10.The spectral study of the faint radio sources in the ELAIS N1 field

Authors:Akriti Sinha, Sarvesh Mangla, Abhirup Datta

Abstract: Understanding the spectral properties of sources is crucial for the characterization of the radio source population. In this work, we have extensively studied the ELAIS N1 field using various low-frequency radio observations. For the first time, we present the 1250\,MHz observations of the field using the upgraded Giant Meterwave Radio Telescope (uGMRT) that reach a central off-source RMS noise of $\sim 12\,\mu$Jy\,beam$^{-1}$. A source catalogue of 1086 sources is compiled at $5\sigma$ threshold ($>60\,\mu$Jy) to derive the normalized differential source counts at this frequency that is consistent with existing observations and simulations. We present the spectral indices derived in two ways: two-point spectral indices and by fitting a power-law. The latter yielded a median $\alpha = -0.57\pm 0.14$, and we identified nine ultra-steep spectrum sources using these spectral indices. Further, using a radio colour diagram, we identify the three mega-hertz peaked spectrum (MPS) sources, while three other MPS sources are identified from the visual inspection of the spectra, the properties of which are discussed. In our study of the classified sources in the ELAIS N1 field, we present the relationship between $\alpha$ and $z$. We find no evidence of an inverse correlation between these two quantities and suggest that the nature of the radio spectrum remains independent of the large-scale properties of the galaxies that vary with redshifts.

1.Aliphatics and Aromatics in the Universe: The Pre-JWST Era

Authors:X. J. Yang, Aigen Li

Abstract: The so-called "unidentified infrared emission" (UIE) features at 3.3, 6.2, 7.7, 8.6, and 11.3 micron ubiquitously seen in a wide variety of astrophysical regions are generally attributed to polycyclic aromatic hydrocarbon (PAH) molecules. Astronomical PAHs often have an aliphatic component (e.g., aliphatic sidegroups like methyl --CH3 may be attached as functional groups to PAHs) as revealed by the detection in many UIE sources of the aliphatic C--H stretching feature at 3.4 micron. With its unprecedented sensitivity, unprecedented spatial resolution and high spectral resolution, the James Webb Space Telescope (JWST) holds great promise for evolutionizing the studies of aliphatics and aromatics in the universe. To facilitate analyzing JWST observations, we present a theoretical framework for determining the aliphatic fractions (\eta_ali) of PAHs, the fractions of C atoms in aliphatic units, from the emission intensity ratios of the 3.4 micron feature to the 3.3 micron feature. To demonstrate the effectiveness of this framework, we compile the 3.3 and 3.4 micron UIE data obtained in the pre-JWST era for an as complete as possible sample, and then apply the framework to these pre-JWST data. We derive a median aliphatic fraction of <\eta_ali>=5.4\% and find that the aliphatic fractions are the highest in protoplanetary nebulae illuminated by cool stars lacking ultraviolet radiation. Nevertheless, the "hardness" of stellar photons is not the only factor affecting the PAH aliphaticity, other factors such as the starlight intensity may also play an important role.

1.New radio lobes at parsec scale from the East-West protostellar jet RAFGL2591

Authors:A. G. Cheriyan, S. Vig, Sreelekshmi Mohan

Abstract: RAFGL2591 is a massive star-forming complex in the Cygnus-X region comprising of a cluster of embedded protostars and young stellar objects located at a distance of 3.33 kpc. We investigate low-frequency radio emission from the protostellar jet associated with RAFGL2591 using the Giant Metrewave Radio Telescope (GMRT) at 325, 610 and 1280 MHz. For the first time, we have detected radio jet lobes in the E-W direction, labelled as GMRT-1 and GMRT-2. While GMRT-1 displays a flat radio spectral index of $\alpha$ = -0.10 , GMRT-2 shows a steeply negative value $\alpha$ = -0.62 suggestive of non-thermal emission. H$_2$ emission maps show the presence of numerous knots, arcs and extended emission towards the East-West jet, excited by the protostar VLA 3. In addition, we report a few H$_2$ knots in the North-East and South-West for the first time. The radio lobes (GMRT-1, GMRT-2) and H$_2$ emission towards this region are understood in the context of the prominent East-West jet as well as its lesser-known sibling jet in the North-East and South-West direction. To model the radio emission from the lobes, we have employed a numerical model including both thermal and non-thermal emission and found number densities towards these lobes in the range 100 - 1000 cm$^{-3}$ . The misalignment of the East-West jet lobes exhibits a reflection symmetry with a bending of $\sim$ 20$\circ$ . We attempt to understand this misalignment through precession caused by a binary partner and/or a supersonic side wind from source(s) in the vicinity.

2.SIMBA-C: An updated chemical enrichment model for galactic chemical evolution in the SIMBA simulation

Authors:Renier T. Hough, Douglas Rennehan, Chiaki Kobayashi, S. Ilani Loubser, Romeel Davé, Arif Babul, Weiguang Cui

Abstract: We introduce a new chemical enrichment and stellar feedback model into GIZMO, using the SIMBA sub-grid models as a base. Based on the state-of-the-art chemical evolution model of Kobayashi et al., SIMBA-C tracks 34 elements from H$\rightarrow$Ge and removes SIMBA's instantaneous recycling approximation. Furthermore, we make some minor improvements to SIMBA's base feedback models. SIMBA-C provides significant improvements on key diagnostics such as the knee of the $z=0$ galaxy stellar mass function, the faint end of the main sequence, and the ability to track black holes in dwarf galaxies. SIMBA-C also matches better with recent observations of the mass-metallicity relation at $z=0,2$. By not assuming instantaneous recycling, SIMBA-C provides a much better match to galactic abundance ratio measures such as [O/Fe] and [N/O]. SIMBA-C thus opens up new avenues to constrain feedback models using detailed chemical abundance measures across cosmic time.

3.The elemental abundances of quiescent galaxies in the LEGA-C survey: the (non-)evolution of [α/Fe] from z = 0.75 to z = 0

Authors:Davide Bevacqua, Paolo Saracco, Francesco La Barbera, Giuseppe D'Ago, Roberto de Propris, Ignacio Ferreras, Anna Gallazzi, Anna Pasquali, Chiara Spiniello

Abstract: We measure the [${\alpha}$/Fe] abundances for 183 quiescent galaxies at z = 0.60 - 0.75 with stellar masses ranging 10.4 \leq log10 10.4 $\leq$ log10 (M$_*$ /M$_\odot$) $\leq$ 11.6 selected from the LEGA-C survey. We estimate [${\alpha}$/Fe] from the ratio of the spectral indices Mgb (${\lambda} \sim 5177$ {\AA}) and Fe4383, compared to predictions of simple stellar population models. We find that 91% of quiescents in our sample have supersolar [${\alpha}$/Fe], with an average value of [${\alpha}$/Fe] = +0.24 $\pm$ 0.01. We find no significant correlation between [${\alpha}$/Fe] and stellar metallicity, mass, velocity dispersion, and average formation time. Galaxies that formed the bulk of their stellar mass on time scales shorter than 1 Gyr follow the same [${\alpha}$/Fe] distribution as those which formed on longer time scales. In comparison to local early-type galaxies and to stacked spectra of quiescent galaxies at z = 0.38 and z = 0.07, we find that the average [${\alpha}$/Fe] has not changed between z = 0.75 and the present time. Our work shows that the vast majority of massive quiescent galaxies at z $\sim$ 0.7 are ${\alpha}$-enhanced, and that no detectable evolution of the average [${\alpha}$/Fe] has taken place over the last $\sim$ 6.5 Gyr.

4.ALMA 300 pc resolution imaging of a z=6.79 quasar: no evidence for supermassive black hole influence on the [C II] kinematics

Authors:Romain A. Meyer, Marcel Neeleman, Fabian Walter, Bram Venemans

Abstract: We present ALMA [C II] 158 $\mu \rm{m}$ and dust continuum observations of the $z=6.79$ quasar J0109--3047 at a resolution of $0."045$ ($\sim$300 pc). The dust and [C II] emission are enclosed within a $\sim 500\, \rm{pc}$ radius, with the central beam ($r<144\ \rm{pc}$) accounting for $\sim$25\% (8\%) of the total continuum ([C II]) emission. The far--infrared luminosity density increases radially from $\sim$5 $\times 10^{11} L_\odot\ \rm{kpc}^{-2}$ to a central value of $\sim$70 $\times 10^{11} L_\odot\ \rm{kpc}^{-2}$ (SFRD $\sim$50-700 $M_\odot\ \rm{yr}^{-1}\ \rm{kpc}^{-2}$). The [C II] kinematics are dispersion-dominated with a constant velocity dispersion of $137 \pm 6 \,\rm{km\ s}^{-1}$. The constant dispersion implies that the underlying mass distribution is not centrally peaked, consistent with the expectations of a flat gas mass profile. The lack of an upturn in velocity dispersion within the central beam is inconsistent with a black hole mass greater than $M_{\rm{BH}}<6.5\times 10^{8}\ M_\odot\ (2\sigma$ level), unless highly fine-tuned changes in the ISM properties conspire to produce a decrease of the gas mass in the central beam comparable to the black hole mass. Our observations therefore imply either that a) the black hole is less massive than previously measured or b) the central peak of the far-infrared and [C II] emission are not tracing the location of the black hole, as suggested by the tentative offset between the near-infrared position of the quasar and the ALMA continuum emission.

5.A Systematic Study of Associations between Supernova Remnants and Molecular Clouds

Authors:Xin Zhou, Yang Su, Ji Yang, Xuepeng Chen, Yan Sun, Zhibo Jiang, Min Wang, Hongchi Wang, Shaobo Zhang, Ye Xu, Qingzeng Yan, Lixia Yuan, Zhiwei Chen, Yiping Ao, Yuehui Ma

Abstract: We universally search for evidence of kinematic and spatial correlation of supernova remnant (SNR) and molecular cloud (MC) associations for nearly all SNRs in the coverage of the MWISP CO survey, i.e. 149 SNRs, 170 SNR candidates, and 18 pure pulsar wind nebulae (PWNe) in 1 deg < l < 230 deg and -5.5 deg < b < 5.5 deg. Based on high quality and unbiased 12CO/13CO/C18O (J = 1--0) survey data, we apply automatic algorithms to identify broad lines and spatial correlations for molecular gas in each SNR region. The 91 percent of SNR-MC associations detected previously are identified in this paper by CO line emission. Overall, there could be as high as 80 percent of SNRs associated with MCs. The proportion of SNRs associated with MCs is high within the Galactic longitude less than ~50 deg. Kinematic distances of all SNRs that are associated with MCs are estimated based on systemic velocities of associated MCs. The radius of SNRs associated with MCs follows a lognormal distribution, which peaks at ~8.1 pc. The progenitor initial mass of these SNRs follows a power-law distribution with an index of ~-2.3 that is consistent with the Salpeter index of -2.35. We find that SNR-MC associations are mainly distributed in a thin disk along the Galactic plane, while a small amount distributed in a thick disk. With the height of these SNRs from the Galactic plane below ~45 pc, the distribution of the average radius relative to the height of them is roughly flat, and the average radius increases with the height when above ~45 pc.

6.On the Significance of the Thick Disks of Disk Galaxies

Authors:Sukyoung K. Yi, J. K. Jang, Julien Devriendt, Yohan Dubois, San Han, Taysun Kimm, Katarina Kraljic, Minjung Park, Sebastien Peirani, Christophe Pichon, Jinsu Rhee

Abstract: Thick disks are a prevalent feature observed in numerous disk galaxies including our own Milky Way. Their significance has been reported to vary widely, ranging from a few to 100% of the disk mass, depending on the galaxy and the measurement method. We use the NewHorizon simulation which has high spatial and stellar mass resolutions to investigate the issue of thick disk mass fraction. We also use the NewHorizon2 simulation that was run on the same initial conditions but additionally traced nine chemical elements. Based on a sample of 27 massive disk galaxies with M* > 10^10 M_{\odot} in NewHorizon, the contribution of the thick disk was found to be 34 \pm 15% in r-band luminosity or 48 \pm 13% in mass to the overall galactic disk, which seems in agreement with observational data. The vertical profiles of 0, 22, and 5 galaxies are best fitted by 1, 2, or 3 sech2 components, respectively. The NewHorizon2 data show that the selection of thick disk stars based on a single [{\alpha}/Fe] cut is severely contaminated by stars of different kinematic properties while missing a bulk of kinematically thick disk stars. Vertical luminosity profile fits recover the key properties of thick disks reasonably well. The majority of stars are born near the galactic mid-plane with high circularity and get heated with time via fluctuation in the force field. Depending on the star formation and merger histories, galaxies may naturally develop thick disks with significantly different properties.

7.Frequency of the dark matter subhalo collisions and bifurcation sequence arising formation of dwarf galaxies

Authors:Koki Otaki, Masao Mori

Abstract: The cold dark matter (CDM) model predicts galaxies have 100 times more dark matter mass than stars. Nevertheless, recent observations report the existence of dark-matter-deficient galaxies with less dark matter than expected. To solve this problem, we investigate the physical processes of galaxy formation in head-on collisions between gas-containing dark matter subhaloes (DMSHs). Analytical estimation of the collision frequency between DMSHs associated with a massive host halo indicates that collisions frequently occur within 1/10th of the virial radius of the host halo, with a collision timescale of about 10 Myr, and the most frequent relative velocity increases with increasing radius. Using analytical models and numerical simulations, we show the bifurcation channel of the formation of dark-matter-dominated and dark-matter-deficient galaxies. In the case of low-velocity collisions, a dark-matter-dominated galaxy is formed by the merging of two DMSHs. In the case of moderate-velocity collisions, the two DMSHs penetrate each other. However the gas medium collides, and star formation begins as the gas density increases, forming a dwarf galaxy without dark matter at the collision surface. In the case of high-velocity collisions, shock-breakout occurs due to the shock waves generated at the collision surface reaching the gas surface, and no galaxy forms. For example, the simulation demonstrates that a pair of DMSHs with a mass of 10^9 Msun containing gas of 0.1 solar metallicity forms a dark-matter-deficient galaxy with a stellar mass of 10^7 Msun for a relative velocity of 200 km/s.

8.UNCOVER: Illuminating the Early Universe -- JWST/NIRSpec Confirmation of $z > 12$ Galaxies

Authors:Bingjie Wang, Seiji Fujimoto, Ivo Labbe, Lukas J. Furtak, Tim B. Miller, David J. Setton, Adi Zitrin, Hakim Atek, Gabriel Brammer, Rachel Bezanson, Joel Leja, Pascal A. Oesch, Sedona H. Price, Iryna Chemerynska, Sam E. Cutler, Pratika Dayal, Pieter van Dokkum, Andy D. Goulding, Jenny E. Greene, Y. Fudamoto, Vasily Kokorev, Richard Pan, John R. Weaver, Katherine E. Whitaker, Christina C. Williams

Abstract: Observations of high-redshift galaxies provide a critical direct test to the theories of early galaxy formation, yet to date, only four have been spectroscopically confirmed at $z>12$. Due to strong gravitational lensing over a wide area, the galaxy cluster field Abell~2744 is ideal for searching for the earliest galaxies. Here we present JWST/NIRSpec observations of two galaxies: a robust detection at $z = 12.40$, and a plausible candidate at $z = 13.08$. The galaxies are discovered in JWST/NIRCam imaging and their distances are inferred with JWST/NIRSpec spectroscopy, all from the JWST Cycle 1 UNCOVER Treasury survey. Detailed stellar population modeling using JWST NIRCam and NIRSpec data corroborates the primeval characteristics of these galaxies: low mass ($\sim 10^8 ~{\rm M_\odot}$), young, rapidly-forming, metal-poor, and star-forming. Interestingly, both galaxies are spatially resolved, having lensing-corrected rest-UV effective radii on the order of 300--400 pc. These sizes are notably larger than other $z>10$ systems, implying significant scatter in the size-mass relation at early times. Deep into the epoch of reionization, these discoveries elucidate the emergence of the first galaxies.

9.Metrewave Galactic Plane with the uGMRT (MeGaPluG) Survey: Lessons from the Pilot Study

Authors:Rohit Dokara, Nirupam Roy, Karl Menten, Sarita Vig, Prasun Dutta, Henrik Beuther, Jagadheep D. Pandian, Michael Rugel, Md Rashid, Andreas Brunthaler

Abstract: Context. The advent of wide-band receiver systems on interferometer arrays enables one to undertake high-sensitivity and high-resolution radio continuum surveys of the Galactic plane in a reasonable amount of telescope time. However, to date, there are only a few such studies of the first quadrant of the Milky Way that have been carried out at frequencies below 1 GHz. The Giant Metrewave Radio Telescope (GMRT) has recently upgraded its receivers with wide-band capabilities (now called the uGMRT) and provides a good opportunity to conduct high resolution surveys, while also being sensitive to the extended structures. Aims. We wish to assess the feasibility of conducting a large-scale snapshot survey, the Metrewave Galactic Plane with the uGMRT Survey (MeGaPluG), to simultaneously map extended sources and compact objects at an angular resolution lower than $10''$ and a point source sensitivity of 0.15 mJy/beam. Methods. We performed an unbiased survey of a small portion of the Galactic plane, covering the W43/W44 regions ($l=29^\circ-35^\circ$ and $|b|<1^\circ$) in two frequency bands: 300$-$500 MHz and 550$-$750 MHz. The 200 MHz wide-band receivers on the uGMRT are employed to observe the target field in several pointings, spending nearly 14 minutes on each pointing in two separate scans. We developed an automated pipeline for the calibration, and a semi-automated self-calibration procedure is used to image each pointing using multi-scale CLEAN and outlier fields. Results. We produced continuum mosaics of the surveyed region at a final common resolution of $25''$ in the two bands that have central frequencies of 400 MHz and 650 MHz, with a point source sensitivity better than 5 mJy/beam. We plan to cover a larger footprint of the Galactic plane in the near future based on the lessons learnt from this study. (Abridged)

10.Signatures of Massive Black Hole Merger Host Galaxies from Cosmological Simulations I: Unique Galaxy Morphologies in Imaging

Authors:Jaeden Bardati, John J. Ruan, Daryl Haggard, Michael Tremmel

Abstract: Low-frequency gravitational wave experiments such as the Laser Interferometer Space Antenna and pulsar timing arrays are expected to detect individual massive black hole (MBH) binaries and mergers. However, secure methods of identifying the exact host galaxy of each MBH merger amongst the large number of galaxies in the gravitational wave localization region are currently lacking. We investigate the distinct morphological signatures of MBH merger host galaxies, using the Romulus25 cosmological simulation. We produce mock telescope images of 201 simulated galaxies in Romulus25 hosting recent MBH mergers, through stellar population synthesis and dust radiative transfer. Based on comparisons to mass- and redshift-matched control samples, we show that combining multiple morphological statistics via a linear discriminant analysis enables identification of the host galaxies of MBH mergers, with accuracies that increase with chirp mass and mass ratio. For mergers with high chirp masses (>10^8.2 Msun) and high mass ratios (>0.5), the accuracy of this approach reaches >80%, and does not decline for at least >1 Gyr after numerical merger. We argue that these trends arise because the most distinctive morphological characteristics of MBH merger and binary host galaxies are prominent classical bulges, rather than relatively short-lived morphological disturbances from their preceding galaxy mergers. Since these bulges are formed though major mergers of massive galaxies, they lead to (and become permanent signposts for) MBH binaries and mergers that have high chirp masses and mass ratios. Our results suggest that galaxy morphology can aid in identifying the host galaxies of future MBH binaries and mergers.

11.Radio Emission From a $z =$ 10.3 Black Hole in UHZ1

Authors:Daniel J. Whalen, Muhammad A. Latif, Mar Mezcua

Abstract: The recent discovery of a 4 $\times$ 10$^7$ M$_{\odot}$ black hole (BH) in UHZ1 at $z =$ 10.3, just 450 Myr after the big bang, suggests that the seeds of the first quasars may have been direct-collapse black holes (DCBHs) from the collapse of supermassive primordial stars at $z \sim$ 20. This object was identified in James Webb Space Telescope (JWST) NIRcam and Chandra X-ray data, but recent studies suggest that radio emission from such a BH should also be visible to the Square Kilometer Array (SKA) and the next-generation Very Large Array (ngVLA). Here, we present estimates of radio flux for UHZ1 from 0.1 - 10 GHz, and find that SKA and ngVLA could detect it with integration times of 10 - 100 hr and just 1 - 10 hr, respectively. It may be possible to see this object with VLA now with longer integration times. The detection of radio emission from UHZ1 would be a first test of exciting new synergies between near infrared (NIR) and radio observatories that could open the era of $z \sim$ 5 - 15 quasar astronomy in the coming decade.

12.Effects of massive central objects on the degree of energy equipartition of globular clusters

Authors:Francisco I. Aros, Enrico Vesperini

Abstract: We present an analysis of the degree of energy equipartition in a sample of 101 Monte Carlo numerical simulations of globular clusters (GCs) hosting either a system of stellar-mass black holes (BHS), an intermediate-mass black hole (IMBH) or neither of them. For the first time, we systematically explore the signatures that the presence of BHS or IMBHs produces on the degree of energy equipartition and if these signatures could be found in current observations. We show that a BHS can halt the evolution towards energy equipartition in the cluster centre. We also show that this effect grows stronger with the number of stellar-mass black holes in the GC. The signatures introduced by IMBHs depend on how dominant their masses are to the GCs and for how long the IMBH has co-evolved with its host GCs. IMBHs with a mass fraction below 2% of the cluster mass produce a similar dynamical effect to BHS, halting the energy equipartition evolution. IMBHs with a mass fraction larger than 2% can produce an inversion of the observed mass-dependency of the velocity dispersion, where the velocity dispersion grows with mass. We compare our results with observations of Galactic GCs and show that the observed range of the degree of energy equipartition in real clusters is consistent with that found in our analysis. In particular, we show that some Galactic GCs fall within the anomalous behaviour expected for systems hosting a BHS or an IMBH and are promising candidates for further dynamical analysis.

13.Composite Bulges -- III. A Study of Nuclear Star Clusters in Nearby Spiral Galaxies

Authors:Aishwarya Ashok, Anil Seth, Peter Erwin, Victor P. Debattista, Adriana de Lorenzo-Cáceres, Dmitri A. Gadotti, Jairo Méndez-Abreu, John E. Beckman, Ralf Bender, Niv Drory, Deanne Fisher, Ulrich Hopp, Matthias Kluge, Tutku Kolcu, Witold Maciejewski, Kianusch Mehrgan, Taniya Parikh, Roberto Saglia, Marja Seidel, Jens Thomas

Abstract: We present photometric and morphological analyses of nuclear star clusters (NSCs) -- very dense, massive star clusters present in the central regions of most galaxies -- in a sample of 33 massive disk galaxies within 20 Mpc, part of the "Composite Bulges Survey." We use data from the Hubble Space Telescope including optical (F475W and F814W) and near-IR (F160W) images from the Wide Field Camera 3. We fit the images in 2D to take into account the full complexity of the inner regions of these galaxies (including the contributions of nuclear disks and bars), isolating the nuclear star cluster and bulge components. We derive NSC radii and magnitudes in all 3 bands, which we then use to estimate NSC masses. Our sample significantly expands the sample of massive late-type galaxies with measured NSC properties. We clearly identify nuclear star clusters in nearly 80% of our galaxies, putting a lower limit on the nucleation fraction in these galaxies that is higher than previous estimates. We find that the NSCs in our massive disk galaxies are consistent with previous NSC mass-NSC radius and Galaxy Mass-NSC Mass relations. However, we also find a large spread in NSC masses, with a handful of galaxies hosting very low-mass, compact clusters. Our NSCs are aligned in PA with their host galaxy disks but are less flattened. They show no correlations with bar or bulge properties. Finally, we find the ratio of NSC to BH mass in our massive disk galaxy sample spans a factor of $\sim$300.

1.The Ultraviolet to Mid-infrared Extinction Law of the Taurus Molecular Cloud Based on the Gaia DR3, GALEX, APASS, Pan-STARRS1, 2MASS, and WISE Surveys

Authors:Ling Li, Shu Wang, Xiaodian Chen, Qingquan Jiang

Abstract: Interstellar dust extinction law is essential for interpreting observations. In this work, we investigate the ultraviolet (UV)--mid-infrared (IR) extinction law of the Taurus molecular cloud and its possible variations. We select 504,988 dwarf stars (4200 K < Teff < 8000 K) and 4,757 giant stars (4200 K < Teff < 5200 K) based on the stellar parameters of Gaia DR3 as tracers. We establish the Teff--intrinsic color relations and determine the intrinsic color indices and color excesses for different types of stars. In the determination of color excess ratios (CERs), we analyze and correct the curvature of CERs and derive the UV--mid-IR CERs of 16 bands. We consider different effective wavelengths for different types of stars when converting CERs to relative extinction, and obtain the extinction law with a better wavelength resolution. In addition, we analyze the possible regional variation of extinction law and derive the average extinction law of Rv=3.13+-0.32 for the Taurus molecular cloud. Only 0.9% of subregions have deviations >3sigma, indicating limited regional variation in the extinction law. We also discuss the effect of Gaia Teff overestimation on the determination of the Taurus extinction law and find that the effect is negligible.

2.Surface Diffusion of Carbon Atoms as a Driver of Interstellar Organic Chemistry

Authors:Masashi Tsuge, Germán Molpeceres, Yuri Aikawa, Naoki Watanabe

Abstract: Many interstellar complex organic molecules (COMs) are believed to be produced on the surfaces of icy grains at low temperatures. Atomic carbon is considered responsible for the skeletal evolution processes, such as C-C bond formation, via insertion or addition reactions. Before reactions, C atoms must diffuse on the surface to encounter reaction partners; therefore, information on their diffusion process is critically important for evaluating the role of C atoms in the formation of COMs. In situ detection of C atoms on ice was achieved by a combination of photostimulated desorption and resonance enhanced multiphoton ionization methods. We found that C atoms weakly bound to the ice surface diffused approximately above 30 K and produced C2 molecules. The activation energy for C-atom surface diffusion was experimentally determined to be 88 meV (1,020 K), indicating that the diffusive reaction of C atoms is activated at approximately 22 K on interstellar ice. The facile diffusion of C at T > 22 K atoms on interstellar ice opens a previously overlooked chemical regime where the increase in complexity of COMs as driven by C atoms. Carbon addition chemistry can be an alternative source of chemical complexity in translucent clouds and protoplanetary disks with crucial implications in our current understanding on the origin and evolution of organic chemistry in our Universe.

3.Open superclusters I: The most populated primordial groups of open clusters in the third quadrant of the Galactic disc

Authors:Juan Casado, Yasser Hendy

Abstract: An open supercluster (OSC) is defined as a cluster of at least six open clusters (OCs) born from the same giant molecular cloud (GMC). We survey the recent catalogs of OCs based on Gaia data and relevant literature to find 17 OSCs of the third galactic quadrant, along with 190 likely members of them. OSCs are frequent enough to be considered an extra class of objects in the hierarchy of star formation. Some of these supersystems are new and most of them contain more members than previously thought. The detailed study of some OSCs has leaded to the discovery of four new young clusters that are members of them, named Casado-Hendy 2 to 5. In certain instances, subgroups with distinct PMs or 3D positions have been found within an OSC, suggesting the presence of multiple generations of stars formed from several bursts of star formation within the same GMC. OSCs are typically unbound and tend to disintegrate on timescales of 0.1 Gyr. The present results support the Primordial Group hypothesis (Casado 2022) and suggest that globular clusters are not formed from the accretion of open superclusters, at least in the local Universe at late times.

4.The Formation of Star-forming Disks in the TNG50 Simulation

Authors:Enci Wang, Simon J. Lilly

Abstract: We investigate the disk formation process in the TNG50 simulation, examining the profiles of SFR surface density ($\Sigma_{\rm SFR}$), gas inflow and outflow, and the evolution of the angular momentum of inflowing gas particles. The TNG50 galaxies tend to have larger star-forming disks, and also show larger deviations from exponential profiles in $\Sigma_{\rm SFR}$ when compared to real galaxies in the MaNGA (Mapping Nearby Galaxies at APO) survey. The stellar surface density of TNG50 galaxies show good exponential profiles, which is found to be the result of strong radial migration of stars over time. However, this strong radial migration of stars in the simulation produces flatter age profiles in TNG50 disks compared to observed galaxies. The star formation in the simulated galaxies is sustained by a net gas inflow and this gas inflow is the primary driver for the cosmic evolution of star formation, as expected from simple gas-regulator models of galaxies. There is no evidence for any significant loss of angular momentum for the gas particles after they are accreted on to the galaxy, which may account for the large disk sizes in the TNG50 simulation. Adding viscous processes to the disks, such as the magnetic stresses from magneto-rotational instability proposed by Wang & Lilly 2022, will likely reduce the sizes of the simulated disks and the tension with the sizes of real galaxies, and may produce more realistic exponential profiles.

1.Neutral atomic and molecular clouds and star formation in the outer Carina arm

Authors:Geumsook Park, Bon-Chul Koo, Kee-Tae Kim, Bruce Elmegreen

Abstract: We present a comprehensive investigation of HI (super)clouds, molecular clouds (MCs), and star formation in the Carina spiral arm of the outer Galaxy. Utilizing HI4PI and CfA CO survey data, we identify HI clouds and MCs based on the ($l$, ${v_\mathrm{LSR}}$) locations of the Carina arm. We analyzed 26 HI clouds and 48 MCs. Most of the identified HI clouds are superclouds, with masses exceeding $10^6~{\mathrm{M_\odot}}$. We find that 15 of these superclouds have associated MC(s) with ${M_\mathrm{HI}} \gtrsim 10^6~{\mathrm{M_\odot}}$ and ${\Sigma_\mathrm{HI+H_2}} \gtrsim$ 50 ${\mathrm{M_\odot}} \rm pc^{-2}$. Our virial equilibrium analysis suggests that these CO-bright HI clouds are gravitationally bound or marginally bound. We report an anti-correlation between molecular mass fractions and Galactocentric distances, and a correlation with total gas surface densities. Nine CO-bright HI superclouds are associated with HII regions, indicating ongoing star formation. We confirm the regular spacing of HI superclouds along the spiral arm, which is likely due to some underlying physical process, such as gravitational instabilities. We observe a strong spatial correlation between HII regions and MCs, with some offsets between MCs and local HI column density peaks. Our study reveals that in the context of HI superclouds, the star formation rate surface density is independent of HI and total gas surface densities but positively correlates with molecular gas surface density. This finding is consistent with both extragalactic studies of the resolved Kennicutt-Schmidt relation and local giant molecular clouds study of Lada et al. (2013), emphasizing the crucial role of molecular gas in regulating star formation processes.

2.On the Effects of Local Environment on Active Galactic Nucleus (AGN) in the Horizon Run 5 Simulation

Authors:Ankit Singh, Changbom Park, Ena Choi, Juhan Kim, Hyunsung Jun, Brad K. Gibson, Yonghwi Kim, Jaehyun Lee, Owain Snaith

Abstract: We use the Horizon Run 5 cosmological simulation to study the effect of galaxy intrinsic properties and the local environment on AGNs characterized by their threshold of the accretion rate. We select galaxies in the stellar mass range $10^{9.5} \le M^{}{*}/M^{}{\odot} \le 10^{10.5}$ in the snapshot at redshift $z$=0.625. Among various intrinsic properties, we find that the star formation rate of the host galaxy is most correlated to the AGN activity. To quantify the environment, we use background galaxy number density (large-scale environment) and distance and morphological type of the nearest neighbors (small-scale environment), and study their relative effects on the AGN properties. We find that, compared to the background density, the nearest neighbor environment is the dominant quantity determining the bolometric luminosity, star formation rate, and kinematic properties of AGNs and better dictates the gas mass of the host galaxy. We show that the cold gas content in the host galaxies is crucial in triggering AGN activity. However, when the nearest neighbor environment effects start to act at the neighbor distance of less than about half the virial radius of the neighbor, the neighbor environmental effects are the most dominant factor for quasar activity.

3.The oblateness of dark matter halos of nearby galaxies and its correlation with gas mass fractions

Authors:Mousumi Das IIA, Roger Ianjamasimanana CSIC, Stacy McGaugh CWRU, James Schombert University of Oregon, K. S. Dwarakanath RRI

Abstract: We present a method to measure the the oblateness parameter q of the dark matter halos of gas rich galaxies that have extended HI disks. We have applied our model to a sample of 20 nearby galaxies that are gas rich and close to face-on, of which 6 are large disk galaxies, 8 have moderate stellar masses and 6 are low surface brightness (LSB) dwarf galaxies. We have used the stacked HI velocity dispersion and HI surface densities to derive q in the outer disk regions. Our most important result is that gas dominated galaxies (such as LSB dwarfs) that have M(gas)/M(baryons)>0.5 have oblate halos (q<0.55), whereas stellar dominated galaxies have a range of q values from 0.2 to 1.3. We also find a significant positive correlation between q and stellar mass, which indicates that galaxies with massive stellar disks have a higher probability of having halos that are spherical or slightly prolate, whereas low mass galaxies preferably have oblate halos. We briefly also discuss how the halo shape affects the disks of galaxies, especially the oblate halos.

4.BASS XXXV. The $M_\rm{BH}$-$σ_\rm{\star}$ Relation of 105-Month Swift-BAT Type 1 AGNs

Authors:Turgay Caglar, Michael J. Koss, Leonard Burtscher, Benny Trakhtenbrot, M. Kiyami Erdim, Julian E. Mejía-Restrepo, Federica Ricci, Meredith C. Powell, Claudio Ricci, Richard Mushotzky, Franz E. Bauer, Tonima T. Ananna, Rudolf E. Bär, Bernhard Brandl, Jarle Brinchmann, Fiona Harrison, Kohei Ichikawa, Darshan Kakkad, Kyuseok Oh, Rogério Riffel, Lia F. Sartori, Krista L. Smith, Daniel Stern, C. Megan Urry

Abstract: We present two independent measurements of stellar velocity dispersions ( $\sigma_\rm{\star}$ ) from the Ca\,H+K \& Mg\,\textsc{i} region (3880--5550~\AA) and the Calcium Triplet region (CaT, 8350--8750~\AA) for 173 hard X-ray-selected Type 1 AGNs ($z \leq$ 0.08) from the 105-month Swift-BAT catalog. We construct one of the largest samples of local Type 1 AGNs that have both single-epoch (SE) 'virial' black hole mass ($M_\rm{BH}$) estimates and $\sigma_\rm{\star}$ measurements obtained from high spectral resolution data, allowing us to test the usage of such methods for SMBH studies. We find that the two independent $\sigma_\rm{\star}$ measurements are highly consistent with each other, with an average offset of only $0.002\pm0.001$ dex. Comparing $M_\rm{BH}$ estimates based on broad emission lines and stellar velocity dispersion measurements, we find that the former is systematically lower by $\approx$0.12 dex. Consequently, Eddington ratios estimated through broad-line $M_\rm{BH}$ determinations are similarly biased (but in the opposite way). We argue that the discrepancy is driven by extinction in the broad-line region (BLR). We also find an anti-correlation between the offset from the $M_\rm{BH}$ - $\sigma_\rm{\star}$ relation and the Eddington ratio. Our sample of Type 1 AGNs shows a shallower $M_\rm{BH}$ - $\sigma_\rm{\star}$ relation (with a power law exponent of $\approx$3.5) compared with that of inactive galaxies (with a power-law exponent of $\approx$4.5), confirming earlier results obtained from smaller samples.

5.Turbulence measurements in the neutral ISM from Hi-21 cm emission-absorption spectra

Authors:Atanu Koley

Abstract: We study the correlation between the non-thermal velocity dispersion ($\sigma_{\rm nth}$) and the length-scale (L) in the neutral interstellar medium (ISM) using a large number of Hi gas components taken from various published Hi surveys and previous Hi studies. We notice that above the length-scale ($L$) of 0.40 pc, there is a power-law relationship between $\sigma_{\rm nth}$ and $L$. However, below 0.40 pc, there is a break in the power-law, where $\sigma_{\rm nth}$ is not significantly correlated with $L$. It has been observed from the Markov chain Monte Carlo (MCMC) method that for the dataset of $L > 0.40$ pc, the most probable values of intensity ($A$) and power-law index ($p$) are 1.14 and 0.55 respectively. Result of $p$ suggests that the power-law is steeper than the standard Kolmogorov law of turbulence. This is due to the dominance of clouds in the cold neutral medium. This is even more clear when we separate the clouds into two categories: one for $L$ is > 0.40 pc and the kinetic temperature ($T_k$ ) is < 250 K, which are in the cold neutral medium (CNM) and for other one where L is > 0.40 pc and T k is between 250 K and 5000 K, which are in the thermally unstable phase (UNM). Most probable values of $A$ and $p$ are 1.14 and 0.67 respectively in the CNM phase and 1.01 and 0.52 respectively in the UNM phase. A greater number of data points is effective for the UNM phase in constructing a more accurate estimate of $A$ and $p$, since most of the clouds in the UNM phase lie below 500 K. However, from the value of $p$ in the CNM phase, it appears that there is a significant difference from the Kolmogorov scaling, which can be attributed to a shock-dominated medium.

6.Similar image retrieval using Autoencoder. I. Automatic morphology classification of galaxies

Authors:Eunsuk Seo, Suk Kim, Youngdae Lee, Sang-Il Han, Hak-Sub Kim, Soo-Chang Rey, Hyunmi Song

Abstract: We present the construction of an image similarity retrieval engine for the morphological classification of galaxies using the Convolutional AutoEncoder (CAE). The CAE is trained on 90,370 preprocessed Sloan Digital Sky Survey galaxy images listed in the Galaxy Zoo 2 (GZ2) catalog. The visually similar output images returned by the trained CAE suggest that the encoder efficiently compresses input images into latent features, which are then used to calculate similarity parameters. Our Tool for Searching a similar Galaxy Image based on a Convolutional Autoencoder using Similarity (TSGICAS) leverages this similarity parameter to classify galaxies' morphological types, enabling the identification of a wider range of classes with high accuracy compared to traditional supervised ML techniques. This approach streamlines the researcher's work by allowing quick prioritization of the most relevant images from the latent feature database. We investigate the accuracy of our automatic morphological classifications using three galaxy catalogs: GZ2, Extraction de Formes Id\'ealis\'ees de Galaxies en Imagerie (EFIGI), and Nair $\&$ Abraham (NA10). The correlation coefficients between the morphological types of input and retrieved galaxy images were found to be 0.735, 0.811, and 0.815 for GZ2, EFIGI, and NA10 catalogs, respectively. Despite differences in morphology tags between input and retrieved galaxy images, visual inspection showed that the two galaxies were very similar, highlighting TSGICAS's superior performance in image similarity search. We propose that morphological classifications of galaxies using TSGICAS are fast and efficient, making it a valuable tool for detailed galaxy morphological classifications in other imaging surveys.

7.The M101 galaxy group as a node in the nearby cosmic filament

Authors:Valentina E. Karachentseva, Igor D. Karachentsev, Elena I. Kaisina, Serafim S. Kaisin

Abstract: We performed a search for faint low surface brightness dwarf galaxies around the major spiral galaxy M\,101 and in the large rectangular area within SGL = [30 -- 80]$^{\circ}$, SGB =[10 -- 37]$^{\circ}$ spanning a chain of galaxies: M\,63, M\,51, M\,101, and NGC\,6503, based on the data from DESI Legacy Imaging Surveys. Six new supposed dwarf members of the complex were discovered. We present a list of 25 prospective members of the M\,101 group and estimate the total mass and the total-mass-to-$K$-band luminosity ratio of the group as $(1.02\pm0.42)\times10^{12}~M_{\odot}$ and $(16.0\pm6.5)~M_{\odot}/L_{\odot}$, respectively. We notice that the average dark mass-to-luminosity ratio in the groups around M\,63, M\,51, and M\,101 is $(12\pm4)M_{\odot}/L_{\odot}$ that almost an order of magnitude lower than the global cosmic ratio, $(102\pm5)M_{\odot}/L_{\odot}$.

8.Exploring the structure and kinematics of the Milky Way through A stars

Authors:J. Ardèvol, M. Monguió, F. Figueras, M. Romero-Gómez, J. M. Carrasco

Abstract: Despite their relatively high intrinsic brightness and the fact that they are more numerous than younger OB stars and kinematically colder than older red giants, A-type stars have rarely been used as Galactic tracers. They may, in fact, be used to fill the age gap between these two tracers, thereby allowing us to study the transition between them. We analyse Galactic disc structure and kinematic perturbations up to 6 kpc from the Sun based on observations of A-type stars. This work presents a catalogue of A-type stars selected using the IGAPS photometric survey. It covers the Galactic disc within $30^{o}\leq l\leq215^{o}$ and $|b|\leq5^{o}$ up to a magnitude of $r\leq19$ mag with about 3.5 million sources. We used Gaia Data Release 3 parallaxes and proper motions, as well as the line-of-sight velocities, to analyse the large-scale features of the Galactic disc. We carried out a study of the completeness of the detected density distributions, along with a comparison between the $b<0^{o}$ and $b>0^{o}$ regions. Possible biases caused by interstellar extinction or by the usage of some kinematic approximations were examined as well. We find stellar overdensities associated with the Local and the Perseus spiral arms, as well as with the Cygnus region. A-type stars also provide kinematic indications of the Galactic warp towards the anticentre, which displays a median vertical motion of ~6-7 km/s at a Galactocentric radius of R=14 kpc. It starts at R=12 kpc, which supports the scenario where the warp begins at larger radii for younger tracers when compared with other samples in the literature. We also detect a region with downward mean motion extending beyond 2 kpc from the Sun towards $60^{o}<l<75^{o}$ that may be associated with a compression breathing mode. Furthermore, A-type stars reveal very clumpy inhomogeneities and asymmetries in the $V_Z$-$V_{\phi}$ velocity space plane.

9.HST-1 as a Window to the Energetics of the Jet Spine of M87

Authors:Brian Punsly

Abstract: A new interpretation of the optical knot in the jet of M87, HST-1, is presented. High sensitivity 22 GHz Very Large Array images locate HST-1 to within 6 mas of the jet axis immediately upstream. 1.7 GHz Very Long Baseline Array images of a bright flare in 2005 indicates that the preponderance of emission in the early stages originates in an elongated region that is tilted $12.5^{\circ}$ from the jet axis. The superluminal motion, shape, location and the large jet-aligned optical/UV polarization suggest an identification with the putative relativistic spine of the jet. As such, energy flux estimates for HST-1, $\sim 870$ mas from the nucleus, published in 2006 indicate that the central engine injected $Q_{\rm{spine}}\approx 2.5 \times 10^{41}\rm{ergs/s}$ into the base of the spine $\sim 200$ years earler. Furthermore, previous studies reveal a tubular protonic jet on sub-mas scales that envelopes a low luminosity core, presumably the faint spine base. It was estimated that the central engine injected $Q_{\rm{tubular\,jet}}\approx 6.1\times 10^{41}\rm{ergs/s}$ $\sim 1.5$ years earlier. If one component of the jet is inherently more powerful, a firm constraint on total jet power in the recent past exists. If the emitted jet is inherently dominated by the spine (tubular jet) then the total bilaterally symmetric jet power emitted from the central engine was $<4Q_{\rm{spine}}\approx 1.0 \times 10^{42}\rm{ergs/s}$ ($< 4Q_{\rm{tubular\,jet}}\approx 2.4\times 10^{42}\rm{ergs/s}$) $\sim 200$ ($\sim 1.5$) years earlier. Assuming a nearly constant central engine injected jet power for $\sim 200$ years indicates a total jet power of $\lesssim 2\times 10^{42}$ ergs/s in epochs of modern observation or $\lesssim 3.5\%$ jet production efficiency for an accretion rate of 0.001$M_{\odot}$/yr.

1.A global view on star formation: The GLOSTAR Galactic plane survey VIII. Formaldehyde absorption in Cygnus~X

Authors:Y. Gong, G. N. Ortiz-León, M. R. Rugel, K. M. Menten, A. Brunthaler, F. Wyrowski, C. Henkel, H. Beuther, S. A. Dzib, J. S. Urquhart, A. Y. Yang, J. D. Pandian, R. Dokara, V. S. Veena, H. Nguyen, S. -N. X. Medina, W. D. Cotton, W. Reich, B. Winkel, P. Müller, I. Skretas, T. Csengeri, S. Khan, A. Cheema

Abstract: Cygnus X is one of the closest and most active high-mass star-forming regions in our Galaxy, making it one of the best laboratories for studying massive star formation. As part of the GLOSTAR Galactic plane survey, we performed large scale simultaneous H$_{2}$CO (1$_{1,0}$-1$_{1,1}$) spectral line and radio continuum imaging observations toward Cygnus X at $\lambda\sim$6 cm with the Karl G. Jansky Very Large Array and the Effelsberg-100 m radio telescope. Our Effelsberg observations reveal widespread H$_{2}$CO (1$_{1,0}$-1$_{1,1}$) absorption with a spatial extent of $\gtrsim$50 pc in Cygnus~X for the first time. On large scales of 4.4 pc, the relative orientation between local velocity gradient and magnetic field tends to be more parallel at H$_{2}$ column densities of $\gtrsim$1.8$\times 10^{22}$~cm$^{-2}$. On the smaller scale of 0.17 pc, our VLA+Effelsberg combined data reveal H$_{2}$CO absorption only toward three bright H{\scriptsize II} regions. Our observations demonstrate that H$_{2}$CO (1$_{1,0}$-1$_{1,1}$) is commonly optically thin. Kinematic analysis supports the assertion that molecular clouds generally exhibit supersonic motions on scales of 0.17-4.4 pc. We show a non-negligible contribution of the cosmic microwave background radiation in producing extended absorption features in Cygnus X. Our observations suggest that H$_{2}$CO ($1_{1,0}-1_{1,1}$) can trace molecular gas with H$_{2}$ column densities of $\gtrsim 5 \times 10^{21}$ cm$^{-2}$. The ortho-H$_{2}$CO fractional abundance with respect to H$_{2}$ has a mean value of 7.0$\times 10^{-10}$. A comparison of velocity dispersions on different linear scales suggests that the dominant $-3$ km s$^{-1}$ velocity component in the prominent DR21 region has nearly identical velocity dispersions on scales of 0.17-4.4 pc, which deviates from the expected behavior of classic turbulence.

2.Constraining gas metal mixing strength in simulations using observations of the Milky Way's disc

Authors:Jorge Sarrato-Alós, Christopher Brook, Arianna Di Cintio

Abstract: This work explores the mixing rate of metals in the interstellar medium (ISM), comparing observational constraints from our solar neighbourhood to high resolution cosmological hydrodynamical simulations of Milky Way (MW)-like galaxies. The mixing rate, described by the coefficient C, is varied in simulations between 0 and 0.05, with resultant simulated galaxies compared to observations of metallicity dispersion in young star clusters, HII regions and neutral gas in the disc of the MW. A value of C between 0.003125 and 0.0125 is found to self-consistently match a range of observables, with a best estimate of C=0.0064$\pm$0.0004. We demonstrate that the relationship between metal dispersion in young stars, HII regions and neutral gas, versus the coefficient C, can be described by a power law. These constrained mixing rates infer a comparatively well mixed ISM in the solar neighbourhood, at odds with some recent observations that have reported a highly inhomogeneous ISM. The degree of mixing suggested by this work is lower than what often employed in many hydrodynamical simulations. Our results have implications for studying the metallicity distribution of stars as well as of gas in the interstellar and circumgalactic media.

3.In Search of Infall Motion in Molecular Clumps. IV. Mapping of the Global Infall Sources

Authors:Yang Yang, Xi Chen, Zhibo Jiang, Zhiwei Chen, Shuling Yu, Jun Li

Abstract: We have used the IRAM 30-m telescope to map some targets with HCO$^+$ (1-0) and H$^{13}$CO$^+$ (1-0) lines in order to search for gas infall evidence in the clumps. In this paper, we report the mapping results for 13 targets. All of these targets show HCO$^+$ emissions, while H$^{13}$CO$^+$ emissions are observed in ten of them. The HCO$^+$ integrated intensity maps of ten targets show clear clumpy structures, and nine targets show clumpy structures in the H$^{13}$CO$^+$ maps. Using the RADEX radiative transfer code, we estimate the column density of H$^{13}$CO$^+$, and determine the abundance ratio [H$^{13}$CO$^+$]/[H$_2$] to be approximately 10$^{-12}$ to 10$^{-10}$. Based on the asymmetry of the HCO$^+$ line profiles, we identify 11 targets show blue profiles, while six clumps have global infall evidence. We use the RATRAN and two-layer models to fit the HCO$^+$ line profiles of these infall sources, and analyze their spatial distribution of the infall velocity. The average infall velocities estimated by these two models are 0.24 -- 1.85 km s$^{-1}$ and 0.28 -- 1.45 km s$^{-1}$, respectively. The mass infall rate ranges from approximately 10$^{-5}$ to 10$^{-2}$ M$_{\odot}$ yr$^{-1}$, which suggests that intermediate- or high-mass stars may be forming in the target regions.

4.Merger-induced star formation in low-metallicity dwarf galaxy NGC 4809/4810

Authors:Yulong Gao, Qiusheng Gu, Guilin Liu, Hongxin Zhang, Yong Shi, Jing Dou, Xiangdong Li, Xu Kong

Abstract: The physical mechanisms driving starbursts in dwarf galaxies are unclear, and the effects of mergers on star formation in these galaxies are still uncertain. We explore how the merger process affects star formation in metal-poor dwarf galaxies by analyzing high-spatial-resolution ($\sim$ 70 pc) integral field spectrograph observations of ionized gas. We use archival data from the Very Large Telescope/Multi Unit Spectroscopic Explorer to map the spatial distribution of strong emission lines (e.g., $\rm H\beta$, $\rm H\alpha$, $\rm [OIII]\lambda5007$, $\rm [NII]\lambda6583$, etc) in the nearby merging star-forming dwarf galaxy system NGC 4809/4810. We identify approximately 112 star-forming knots scattered among the two galaxies, where the gas-phase metallicity distribution is inhomogeneous and mixing with metal-poor and metal-rich ionized gas. Star-forming knots at the interacting region show lower metallicity, the highest star formation rates (SFRs) and SFR to resolved main-sequence-relation (rMSR) ratios. Ionized gas exhibits an obvious northeast-southwest velocity gradient in NGC 4809, while seemingly mixed in NGC 4810. High virial parameters and the stellar mass-size relation of HII regions indicate that these regions are dominated by direct radiation pressure from massive stars/clusters and persistently expanding. We find two different stellar mass surface density-stellar age relations in NGC 4809 and NGC 4810, and the stellar ages of NGC 4810 are systematically younger than in NGC 4809. Our study suggests that the merging stage of two dwarf galaxies can induce starburst activities at the interaction areas, despite the metal-deficient environment. Considering the high specific SFRs and different stellar ages, we propose that the interaction initially triggered star formation in NGC 4809 and then drove star formation in NGC 4810.

5.JADES. The diverse population of infant Black Holes at 4<z<11: merging, tiny, poor, but mighty

Authors:Roberto Maiolino, Jan Scholtz, Emma Curtis-Lake, Stefano Carniani, William Baker, Anna de Graaff, Sandro Tacchella, Hannah Übler, Francesco D'Eugenio, Joris Witstok, Mirko Curti, Santiago Arribas, Andrew J. Bunker, Stéphane Charlot, Jacopo Chevallard, Daniel J. Eisenstein, Eiichi Egami, Zhiyuan Ji, Gareth C. Jones, Jianwei Lyu, Tim Rawle, Brant Robertson, Wiphu Rujopakarn, Michele Perna, Fengwu Sun, Giacomo Venturi, Christina C. Williams, Chris Willott

Abstract: We present 12 new AGN at 4<z<7 in the JADES survey (in addition to the previously identified AGN in GN-z11 at z=10.6) revealed through the detection of a Broad Line Region as seen in the Balmer emission lines. The depth of JADES, together with the use of three different spectral resolutions, enables us to probe a lower mass regime relative to previous studies. In a few cases we find evidence for two broad components of Halpha which suggests that these could be candidate merging black holes (BHs). The inferred BH masses range between 8 x 10^7 Msun down to 4 x 10^5 Msun, interestingly probing the regime expected for Direct Collapse Black Holes. The inferred AGN bolometric luminosities (~10^44-10^45 erg/s) imply accretion rates that are < 0.5 times the Eddington rate in most cases. However, small BH, with M_BH ~ 10^6 Msun, tend to accrete at Eddington or super-Eddington rates. These BH at z~4-11 are over-massive relative to their host galaxies stellar masses when compared to the local M_BH-Mstar relation. However, we find that these early BH tend to be more consistent with the local relation between M_BH and velocity dispersion, as well as between M_BH and dynamical mass, suggesting that these are more fundamental and universal relations. On the BPT excitation-diagnostic diagram these AGN are located in the region that is that is locally occupied by star-forming galaxies, implying that they would be missed by the standard classification techniques if they did not display broad lines. Their location on the diagram is consistent with what expected for AGN hosted in metal poor galaxies (Z ~ 0.1-0.2 Zsun). The fraction of broad line AGN with L_AGN > 10^44 erg/s, among galaxies in the redshift range 4<z<6, is about 10%, suggesting that the contribution of AGN and their hosts to the reionization of the Universe is > 10%.

6.The Star Formation Across Cosmic Time (SFACT) Survey. II. The First Catalog from a New Narrow-Band Survey for Emission-Line Objects

Authors:Jennifer Sieben, David J. Carr, John J. Salzer, Alec S. Hirschauer

Abstract: Star Formation Across Cosmic Time (SFACT) is a new narrowband survey designed to detect faint emission-line galaxies and QSOs over a broad range of redshifts. Here we present the first list of SFACT candidates from our pilot-study fields. Using the WIYN 3.5m telescope, we are able to achieve good image quality with excellent depth and routinely detect ELGs to r = 25.0. The limiting line flux of the survey is ~1.0 x 10^16 erg/s/cm^2. SFACT targets three primary emission lines: H-alpha, [O III]5007, and [O II]3727. The corresponding redshift windows allow for the detection of objects at z ~ 0-1. With a coverage of 1.50 square degrees in our three pilot-study fields, a total of 533 SFACT candidates have been detected (355 candidates per square degree). We detail the process by which these candidates are selected in an efficient and primarily automated manner, then tabulate accurate coordinates, broadband photometry, and narrowband fluxes for each source.

7.A Parsec-Scale Galactic 3D Dust Map out to 1.25 kpc from the Sun

Authors:Gordian Edenhofer, Catherine Zucker, Philipp Frank, Andrew K. Saydjari, Joshua S. Speagle, Douglas Finkbeiner, Torsten Enßlin

Abstract: High-resolution 3D maps of interstellar dust are critical for probing the underlying physics shaping the structure of the interstellar medium, and for foreground correction of astrophysical observations affected by dust. We aim to construct a new 3D map of the spatial distribution of interstellar dust extinction out to a distance of 1.25 kpc from the Sun. We leverage distance and extinction estimates to 54 million nearby stars derived from the Gaia BP/RP spectra. Using the stellar distance and extinction information, we infer the spatial distribution of dust extinction. We model the logarithmic dust extinction with a Gaussian Process in a spherical coordinate system via Iterative Charted Refinement and a correlation kernel inferred in previous work. We probe our 661 million dimensional posterior distribution using the variational inference method MGVI. Our 3D dust map achieves an angular resolution of 14' (Nside = 256). We sample the dust extinction in 516 distance bins spanning 69 pc to 1250 pc. We obtain a maximum distance resolution of 0.4 pc at 69 pc and a minimum distance resolution of 7 pc at 1.25 kpc. Our map resolves the internal structure of hundreds of molecular clouds in the solar neighborhood and will be broadly useful for studies of star formation, Galactic structure, and young stellar populations. It is available for download in a variety of coordinate systems at and can also be queried via the publicly available dustmaps Python package.

8.The Star Formation Across Cosmic Time (SFACT) Survey. III. Spectroscopy of the Initial Catalog of Emission-Line Objects

Authors:David J. Carr, Jennifer Sieben, John J. Salzer, Samantha W. Brunker, Bryce Cousins

Abstract: The Star Formation Across Cosmic Time (SFACT) survey is a new narrowband survey designed to detect emission-line galaxies (ELGs) and quasi-stellar objects (QSOs) over a wide range of redshifts in discrete redshift windows. The survey utilizes the WIYN 3.5m telescope and the Hydra multifiber positioner to perform efficient follow-up spectroscopy on galaxies identified in the imaging part of the survey. Since the objects in the SFACT survey are selected by their strong emission lines, it is possible to obtain useful spectra for even the faintest of our sources (r ~ 25). Here we present the 453 objects that have spectroscopic data from the three SFACT pilot-study fields, 415 of which are confirmed ELGs. The methodology for processing and measuring these data is outlined in this paper and example spectra are displayed for each of the three primary emission lines used to detect objects in the survey (H-alpha, [O III]5007, and [O II]3727). Spectra of additional QSOs and non-primary emission-line detections are also shown as examples. The redshift distribution of the pilot-study sample is examined and the ELGs are placed in different emission-line diagnostic diagrams in order to distinguish the star-forming galaxies from the active galactic nuclei.

1.The formation pathways of compact elliptical galaxies

Authors:Simon Deeley, Michael Drinkwater, Sarah Sweet, Kenji Bekki, Warrick Couch, Duncan Forbes

Abstract: Compact elliptical (cE) galaxies remain an elusively difficult galaxy class to study. Recent observations have suggested that isolated and host-associated cEs have different formation pathways, while simulation studies have also shown different pathways can lead to a cE galaxy. However a solid link has not been established, and the relative contributions of each pathway in a cosmological context remains unknown. Here we combine a spatially-resolved observational sample of cEs taken from the SAMI galaxy survey with a matched sample of galaxies within the IllustrisTNG cosmological simulation to establish an overall picture of how these galaxies form. The observed cEs located near a host galaxy appear redder, smaller and older than isolated cEs, supporting previous evidence for multiple formation pathways. Tracing the simulated cEs back through time, we find two main formation pathways; 32 $\pm$ 5 percent formed via the stripping of a spiral galaxy by a larger host galaxy, while 68 $\pm$ 4 percent formed through a gradual build-up of stellar mass in isolated environments. We confirm that cEs in different environments do indeed form via different pathways, with all isolated cEs in our sample having formed via in-situ formation (i.e. none were ejected from a previous host), and 77 $\pm$ 6 percent of host-associated cEs having formed via tidal stripping. Separating them by their formation pathway, we are able to reproduce the observed differences between isolated and host-associated cEs, showing that these differences can be fully explained by the different formation pathways dominating in each environment.

2.A detached double X-ray tail in the merging galaxy cluster Z8338 with a large double tail

Authors:Chong Ge, Ming Sun, Paul E. J. Nulsen, Craig Sarazin, Maxim Markevitch, Gerrit Schellenberger

Abstract: When subhalos infall into galaxy clusters, their gas content is ram pressure stripped by the intracluster medium (ICM) and may turn into cometary tails. We report the discovery of two spectacular X-ray double tails in a single galaxy cluster, Z8338, revealed by 70 ks Chandra observations. The brighter one, with an X-ray bolometric luminosity of $3.9 \times 10^{42}{\rm\ erg\ s}^{-1}$, is a detached tail stripped from the host halo and extended at least 250 kpc in projection. The head of the detached tail is a cool core with the front tip of the cold front $\sim$ 30 kpc away from the nucleus of its former host galaxy. The cooling time of the detached cool core is $\sim 0.3$ Gyr. For the detached gas, the gravity of the once-associated dark matter halo further enhances the Rayleigh-Taylor (RT) instability. From its survival, we find that a magnetic field of a few $\mu$G is required to suppress the hydrodynamic instability. The X-ray temperature in the tail increases from 0.9 keV at the front tip to 1.6 keV in the wake region, which suggests the turbulent mixing with the hotter ICM. The fainter double X-ray tail, with a total X-ray luminosity of $2.7 \times 10^{42}{\rm\ erg\ s}^{-1}$, appears to stem from the cool core of a subcluster in Z8338, and likely was formed during the ongoing merger. This example suggests that X-ray cool cores can be displaced and eventually destroyed by mergers, while the displaced cool cores can survive for some extended period of time.

3.Using KCWI to Explore the Chemical Inhomogeneities and Evolution of J1044+0353

Authors:Zixuan Peng, Crystal L. Martin, Pierre Thibodeaux, Jichen Zhang, Weida Hu, Yuan Li

Abstract: J1044+0353 is considered a local analog of the young galaxies that ionized the intergalactic medium at high-redshift due to its low mass, low metallicity, high specific star formation rate, and strong high-ionization emission lines. We use integral field spectroscopy to trace the propagation of the starburst across this small galaxy using Balmer emission- and absorption-line equivalent widths and find a post-starburst population (~ 15 - 20 Myr) roughly one kpc east of the much younger, compact starburst (~ 3 - 4 Myr). Using the direct electron temperature method to map the O/H abundance ratio, we find similar metallicity (1 to 3 sigma) between the starburst and post-starburst regions but with a significant dispersion of about 0.3 dex within the latter. We also map the Doppler shift and width of the strong emission lines. Over scales several times the size of the galaxy, we discover a velocity gradient parallel to the galaxy's minor axis. The steepest gradients (~ 30 $\mathrm{km \ s^{-1} \ kpc^{-1}}$) appear to emanate from the oldest stellar association. We identify the velocity gradient as an outflow viewed edge-on based on the increased line width and skew in a biconical region. We discuss how this outflow and the gas inflow necessary to trigger the starburst affect the chemical evolution of J1044+0353. We conclude that the stellar associations driving the galactic outflow are spatially offset from the youngest association, and a chemical evolution model with a metal-enriched wind requires a more realistic inflow rate than a homogeneous chemical evolution model.

4.Self-consistent dynamical models with a finite extent -- III. Truncated power-law spheres

Authors:Maarten Baes, Bert Vander Meulen

Abstract: Fully analytical dynamical models usually have an infinite extent, while real star clusters, galaxies, and dark matter haloes have a finite extent. The standard method for generating dynamical models with a finite extent consists of taking a model with an infinite extent and applying a truncation in binding energy. This method, however, cannot be used to generate models with a pre-set analytical mass density profile. We investigate the self-consistency and dynamical properties of a family of power-law spheres with a general tangential Cuddeford (TC) orbital structure. By varying the density power-law slope $\gamma$ and the central anisotropy $\beta_0$, these models cover a wide parameter space in density and anisotropy profiles. We explicitly calculate the phase-space distribution function for various parameter combinations, and interpret our results in terms of the energy distribution of bound orbits. We find that truncated power-law spheres can be supported by a TC orbital structure if and only if $\gamma \geqslant 2\beta_0$, which means that the central density slope-anisotropy inequality is both a sufficient and a necessary condition for this family. We provide closed expressions for structural and dynamical properties such as the radial and tangential velocity dispersion profiles, which can be compared against more complex numerical modelling results. This work significantly adds to the available suite of self-consistent dynamical models with a finite extent and an analytical description.

5.The Infrared Extinction Law in the Ophiuchus Molecular Cloud based on UKIDSS and Spitzer

Authors:Jun Li, Xi Chen

Abstract: Investigating the extinction properties in dense molecular clouds is of significant importance for understanding the behavior of interstellar dust and its impact on observations. In this study, we comprehensively examined the extinction law in the Ophiuchus cloud across a wavelength range from 0.8$\,\mu\rm m$ to 8$\,\mu\rm m$. To achieve this, we analyzed NIR and MIR data obtained from the UKIDSS GCS and the Spitzer c2d survey, respectively. By fitting a series of color-color diagrams, we determined color-excess ratios $E_{J-\lambda}/E_{J-K}$ for seven passbands. These ratios were then directly converted to derive the relative extinction law $A_\lambda/A_K$. Our findings demonstrate that the Ophiuchus cloud exhibits a characteristic of flat MIR extinction, consistent with previous studies. Additionally, our results reveal variations in the extinction law with extinction depth, indicating a flatter trend from the NIR to MIR bands as extinction increases. Notably, our analysis reveals no significant difference in the MIR extinction law among the four dark clouds: L1712, L1689, L1709, and L1688. However, distinct variations were observed in the extinction law for regions outside the dark clouds, specifically L1688N and L1688W. These regions displayed lower color-excess ratios $E_{J-\lambda}/E_{J-K}$ in the Spitzer/IRAC bands. This observation lends support to the dust growth occurring in the dense regions of the Ophiuchus cloud.

6.Identification of Galaxy Protoclusters Based on the Spherical Top-hat Collapse Model

Authors:Jaehyun Lee, Changbom Park, Juhan Kim, Christophe Pichon, Brad K. Gibson, Jihye Shin, Yonghwi Kim, Owain N. Snaith, Yohan Dubois, C. Gareth Few

Abstract: We propose a new method for finding galaxy protoclusters that is motivated by structure formation theory, and is also directly applicable to observations. Protoclusters are defined as the galaxy groups whose virial mass $M_{\rm vir} < 10^{14}\,M_{\odot}$ at their epochs but would exceed that limit by $z=0$. They are distinguished from clusters, groups of galaxies whose virial mass currently exceeds $10^{14}\,M_{\odot}$. According to these definitions there can be a mixture of clusters and protoclusters at a given epoch. The future mass that a protocluster would acquire at $z=0$ is estimated using the spherical collapse model. The centers of protoclusters are identified using the critical overdensity for collapse by $z=0$ that is predicted by the spherical collapse model, and the physical size of protoclusters is defined by the overdensity corresponding to the turnaround radius. We use the cosmological hydrodynamical simulation Horizon Run 5 (HR5) to calibrate this prescription and demonstrate its performance. We find that the protocluster identification method suggested in this study is quite successful. Its application to the high redshift HR5 galaxies shows a tight correlation between the mass within the protocluster regions identified according to the spherical collapse model and the final mass to be found within the cluster at $z=0$, meaning that the regions can be regarded as the bona-fide protoclusters with high reliability.

1.Deep learning forecasts of cosmic acceleration parameters from DECi-hertz Interferometer Gravitational-wave Observatory

Authors:Meng-Fei Sun, Jin Li, Shuo Cao, Xiaolin Liu

Abstract: Validating the accelerating expansion of the universe is an important issue for understanding the evolution of the universe. By constraining the cosmic acceleration parameter $X_H$, we can discriminate between the $\Lambda \mathrm{CDM}$ (cosmological constant plus cold dark matter) model and LTB (the Lema\^itre-Tolman-Bondi) model. In this paper, we explore the possibility of constraining the cosmic acceleration parameter with the inspiral gravitational waveform of neutron star binaries (NSBs) in the frequency range of 0.1Hz-10Hz, which can be detected by the second-generation space-based gravitational wave detector DECIGO. We use a convolutional neural network (CNN), a long short-term memory (LSTM) network combined with a gated recurrent unit (GRU), and Fisher information matrix to derive constraints on the cosmic acceleration parameter $X_H$. Based on the simulated gravitational wave data with a time duration of 1 month, we conclude that CNN can limit the relative error to 14.09%, while LSTM network combined with GRU can limit the relative error to 13.53%. Additionally, using Fisher information matrix for gravitational wave data with a 5-year observation can limit the relative error to 32.94%. Compared with the Fisher information matrix method, deep learning techniques will significantly improve the constraints on the cosmic acceleration parameters at different redshifts. Therefore, DECIGO is expected to provide direct measurements of the acceleration of the universe, by observing the chirp signals of coalescing binary neutron stars.

2.Constraining a companion of the galactic center black hole, Sgr A*

Authors:Clifford M. Will, Smadar Naoz, Aurélien Hees, Alexandria Tucker, Eric Zhang, Tuan Do, Andrea Ghez

Abstract: We use 23 years of astrometric and radial velocity data on the orbit of the star S0-2 to constrain a hypothetical intermediate-mass black hole orbiting the massive black hole Sgr A* at the Galactic center. The data place upper limits on variations of the orientation of the stellar orbit (inclination, nodal angle, and pericenter) at levels between 0.02 and 0.07 degrees per year. We use a combination of analytic estimates and full numerical integrations of the orbit of S0-2 in the presence of a black-hole binary. For a companion IMBH whose semi-major axis $a_c$ is larger than that of S0-2 (1020 a.u.), we find that in the region between 1000 and 4000 a.u., a companion black hole with mass $m_c$ between $10^3$ and $10^5 M_\odot$ is excluded, with a boundary behaving as $a_c \sim m_c^{1/3}$. For a companion with $a_c < 1020$ a.u., we find that a black hole with mass between $10^3$ and $10^5 \, M_\odot$ is again excluded, with a boundary behaving as $a_c \sim m_c^{-1/2}$. These bounds arise from quadrupolar perturbations of the orbit of S0-2. However, significantly stronger bounds on the mass of an inner companion arise from the fact that the location of S0-2 is measured relative to the bright emission of Sgr A*. As a consequence, that separation is perturbed by the ``wobble'' of Sgr A* about the center of mass between it and the companion, leading to ``apparent'' perturbations of S0-2's orbit that also include a dipole component. The result is a set of bounds as small as $400 \, M_\odot$ at 200 a.u.; the numerical simulations suggest a bound from these effects varying as $a_c \sim m_c^{-1}$. We compare and contrast our results with those from a recent analysis by the GRAVITY collaboration.

3.Effects of Grain Magnetic Properties and Grain Growth on Synthetic Dust Polarization of MHD Simulations in Protostellar Environments

Authors:Nguyen Chau Giang, Thiem Hoang

Abstract: Thermal dust polarization is a powerful tool to probe magnetic fields ($\textbf{B}$), grain magnetic properties, and grain sizes. However, a systematic study of the dependence of synthetic dust polarization on grain properties in protostellar environments is not yet available. In this paper, we post-process a non-ideal MHD simulation of a collapsing protostellar core with our updated POLARIS to study in detail the effects of grain magnetic properties and grain growth on dust polarization. We found that superparamagnetic (SPM) grains can produce high polarization degree $p \sim 10-40\%$ beyond $\sim 500$ au because of their efficient magnetic alignment by magnetically enhanced Radiative Torque (MRAT) mechanism. The magnetic field tangling due to turbulence in the envelope causes the decrease of $p$ with emission intensity $I$ as $p\propto I^{\alpha}$ with the slope $\alpha \sim -0.3$. But within 500 au, SPM grains tend to have weak internal alignment and be aligned with $\textbf{B}$ by RAdiative Torque mechanism only, producing lower $p \sim 1\%$ and larger $\alpha \sim -0.6$. For paramagnetic (PM) grains, their inefficient magnetic alignment produces $p << 1\%$, and the depolarization happens with a steep slope of $\alpha \sim -0.9$ owing to the alignment loss of large grains toward the protostar. Grain growth can help to increase $p$ and weaken the depolarization effect caused by turbulence beyond $500$ au for SPM grains. But for SPM grains within $\sim 500$ au and for PM grains, increasing $a_{\rm max}$ enhances the depolarization effect due to the increasing amount of large grains with inefficient alignment. Finally, we found that the polarization angle dispersion function $S$ increases with increasing iron inclusions and $a_{\rm max}$. Our findings reveal the dependence of magnetic field strength measured using the Davis-Chandrashekhar-Fermi technique on grain alignment degree.

4.The intrinsic X-ray luminosity distribution of an optically-selected SDSS quasar population

Authors:Amy L. Rankine, James Aird, Angel Ruiz, Antonis Georgakakis

Abstract: In active galactic nuclei, the relationship between UV and X-ray luminosity is well studied (often characterised by $\alpha_\text{ox}$) but often with heterogeneous samples. We have parametrized the intrinsic distribution of X-ray luminosity, $L_\text{X}$, for the optically-selected sample of SDSS quasars in the Stripe 82 and XXL fields across redshifts 0.5-3.5. We make use of the available XMM observations and a custom pipeline to produce Bayesian sensitivity curves that are used to derive the intrinsic X-ray distribution in a hierarchical Bayesian framework. We find that the X-ray luminosity distribution is well described by a Gaussian function in ${\log_{10}}L_\text{X}$ space with a mean that is dependent on the monochromatic 2500A UV luminosity, $L_{2500}$. We also observe some redshift dependence of the distribution. The mean of the $L_\text{X}$ distribution increases with redshift while the width decreases. This weak but significant redshift dependence leads to $L_{2500}$-$L_\text{X}$ and $L_{2500}$-$\alpha_\text{ox}$ relations that evolve with redshift, and we produce a redshift- and $L_{2500}$-dependent $\alpha_\text{ox}$ equation. The increasing average black hole mass with redshift in our sample points to black hole mass as a potential driver of the redshift evolution.

1.Photometric Selection of Unobscured QSOs in the Ecliptic Poles: KMTNet in the South Field and Pan-STARRS in the North Field

Authors:Woowon Byun, Minjin Kim, Yun-Kyeong Sheen, Dongseob Lee, Luis C. Ho, Jongwan Ko, Kwang-Il Seon, Hyunjin Shim, Dohyeong Kim, Yongjung Kim, Joon Hyeop Lee, Hyunjin Jeong, Jong-Hak Woo, Woong-Seob Jeong, Byeong-Gon Park, Sang Chul Kim, Yongseok Lee, Sang-Mok Cha, Hyunmi Song, Donghoon Son, Yujin Yang

Abstract: We search for quasi-stellar objects (QSOs) in a wide area of the south ecliptic pole (SEP) field, which has been and will continue to be intensively explored through various space missions. For this purpose, we obtain deep broadband optical images of the SEP field covering an area of $\sim$$14.5\times14.5$ deg$^2$ with the Korea Microlensing Telescope Network. The 5$\sigma$ detection limits for point sources in the $BVRI$ bands are estimated to be $\sim$22.59, 22.60, 22.98, and 21.85 mag, respectively. Utilizing data from Wide-field Infrared Survey Explorer, unobscured QSO candidates are selected among the optically point-like sources using the mid-infrared (MIR) and optical-MIR colors. To further refine our selection and eliminate any contamination not adequately removed by the color-based selection, we perform the spectral energy distribution fitting with archival photometric data ranging from optical to MIR. As a result, we identify a total of 2,383 unobscured QSO candidates in the SEP field. We also apply a similar method to the north ecliptic pole field using the Pan-STARRS data and obtain a similar result of identifying 2,427 candidates. The differential number count per area of our QSO candidates is in good agreement with those measured from spectroscopically confirmed ones in other fields. Finally, we compare the results with the literature and discuss how this work will be implicated in future studies, especially with the upcoming space missions.

2.Mapping the Milky Way's stellar halo with 2D data

Authors:Anda Chen, Zhigang Li, Yougang Wang, Yan Gong, Xuelei Chen, Richard J. Long

Abstract: We propose a new method for measuring the spatial density distribution of the stellar halo of the Milky Way. Our method is based on a pairwise statistic of the distribution of stars on the sky, the angular two-point correlation function (ATPCF). The ATPCF utilizes two dimensional data of stars only and is therefore immune to the large uncertainties in the determination of distances to stars. We test our method using mock stellar data coming from various models including the single power-law (SPL) and the broken power-law (BPL) density profiles. We also test the influence of axisymmetric flattening factors using both constant and varying values. We find that the ATPCF is a powerful tool for recovering the spatial distributions of the stellar halos in our models. We apply our method to observational data from the type ab RR Lyrae catalog in the Catalina Survey Data Release 1. In the 3-parameter BPL model, we find that $s_{1}=2.46_{-0.20}^{+0.18}, s_{2}=3.99_{-1.33}^{+0.75}$ and $r_{0}=31.11_{-5.88}^{+7.61}$, which are in good agreement with previous results. We also find that introducing an extra parameter, the radially varying flattening factor, greatly improves our ability to model accurately the observed data distribution. This implies perhaps that the stellar halo of the Milky Way should be regarded as oblate.

3.A cautionary lesson from Gaia systematics: the mono-metallic globular cluster NGC 5904

Authors:Paolo Bianchini, Alessandra Mastrobuono-Battisti

Abstract: The study of the chemistry of the stellar populations in Globular Clusters (GCs) is a fundamental task to unveil their formation in the high-redshift universe and to reconstruct the build up of our Galaxy. Recently, using metallicity estimates from BP/RP low-resolution Gaia DR3 spectra, Piatti 2023 presented the surprising detection of two distinct stellar populations in the stellar stream of the GC NGC 5904, otherwise considered a mono-metallic system. The presence of these two populations, with [Fe/H]~-1.4 and [Fe/H]~-2.0 dex, was taken as the evidence of a merger origin of the cluster. In this Letter, using the same data set complemented by the new robust metallicity estimates by Andrae et al. 2023b, we carry out a detailed analysis of the metallicity distribution of stars belonging both to the cluster and to its stellar stream, explicitly focusing on the subtle effects of data systematics. We demonstrate that the population at [Fe/H]~-2.0 dex is a data artefact due to error systematics, affecting especially low-magnitude stars. The new higher quality metallicity sample corroborates this finding, and it indicates the presence of only a population of stars with metallicity of [Fe/H]~-1.3 dex, in agreement with previous literature studies. We, therefore, conclude that both NGC 5904 and its stellar stream are mono-metallic systems, and emphasize the need of carefully examining systematic effects in large and complex data bases.

4.Evolution of the Lyman-α emitting fraction and UV properties of lensed star-forming galaxies between 2.9 < z < 6.7

Authors:Ilias Goovaerts, Roser Pello, Tran Thi Thai, Pham Tuan-Anh, Johan Richard, Adélaïde Claeyssens, Emile Carinos, Geoffroy de la Vieuville, Jorryt Matthee

Abstract: Faint galaxies are theorised to have played a major role in reionising the Universe. Their properties as well as the Lyman-{\alpha} emitter fraction, could provide useful insight into this epoch. We use four galaxy clusters from the Lensed Lyman-alpha MUSE Arcs Sample (LLAMAS) which also have deep HST photometry to select a population of intrinsically faint Lyman Break Galaxies (LBGs) and Lyman-alpha Emitters (LAEs). We study the interrelation of these two populations, their properties, and the fraction of LBGs that display Lyman-alpha emission. The use of lensing clusters allows us to access an intrinsically faint population, the largest sample collected for this purpose: 263 LAEs and 972 LBGs between redshifts of 2.9 and 6.7, Lyman-alpha luminosities between 39.5 < log(L)(erg/s) < 42 and absolute UV magnitudes between -22 < M1500 < -12. We find a redshift evolution of the Lyman-alpha emitter fraction in line with past results, with diminished values above z = 6, taken to signify an increasingly neutral intervening IGM. Inspecting this redshift evolution with different limits on Lyman-alpha equivalent width (EW) and M1500 we find that the Lyman-alpha emitter fraction for the UV-brighter half of our sample is higher than the fraction for the UV-fainter half, a difference which increases at higher redshift. This is a surprising result and can be interpreted as a population of low Lyman-alpha EW, UV-bright galaxies situated in reionised bubbles. This result is especially interesting in the context of similar, UV-bright, low Lyman-alpha EW objects recently detected around the epoch of reionisation. We extend to intrinsically fainter objects the previously observed trends of LAEs among LBGs as galaxies with high star-formation rates and low dust content, as well as the strongest LAEs having in general fainter UV magnitudes and steeper UV slopes.

5.Towards a reliable prediction of the infrared spectra of cosmic fullerenes and their derivatives in the JWST era

Authors:Jianzhi Xu, Aigen Li, Xiaohu Li, Gao-Lei Hou

Abstract: Fullerenes, including C60, C70, and C60+, are widespread in space through their characteristic infrared vibrational features (C60+ also reveals its presence in the interstellar medium through its electronic transitions) and offer great insights into the carbon chemistry and stellar evolution. The potential existence of fullerene-related species in space has long been speculated and recently put forward by a set of laboratory experiments of C60+, C60H+, C60O+, C60OH+, C70H+, and [C60-Metal]+ complexes. The advent of the James Webb Space Telescope (JWST) provides a unique opportunity to search for these fullerene-related species in space. To facilitate JWST search, analysis, and interpretation, an accurate knowledge of their vibrational properties is essential. Here, we compile a VibFullerene database and conduct a systematic theoretical study on those species. We derive a set of range-specific scaling factors for vibrational frequencies, to account for the deficiency of density functional theory calculations in predicting the accurate frequencies. Scaling factors with low root-mean-square and median errors for the frequencies are obtained, and their performance is evaluated, from which the best-performing methods are recommended for calculating the infrared spectra of fullerene derivatives which balance the accuracy and computational cost. Finally, the recommended vibrational frequencies and intensities of fullerene derivatives are presented for future JWST detection.

1.Graph Theoretical Analysis of local ultraluminous infrared galaxies and quasars

Authors:Orestis Pavlou, Ioannis Michos, Vicky Papadopoulou Lesta, Michalis Papadopoulos, Evangelos S. Papaefthymiou, Andreas Efstathiou

Abstract: We present a methodological framework for studying galaxy evolution by utilizing Graph Theory and network analysis tools. We study the evolutionary processes of local ultraluminous infrared galaxies (ULIRGs) and quasars and the underlying physical processes, such as star formation and active galactic nucleus (AGN) activity, through the application of Graph Theoretical analysis tools. We extract, process and analyse mid-infrared spectra of local (z < 0.4) ULIRGs and quasars between 5-38 microns through internally developed Python routines, in order to generate similarity graphs, with the nodes representing ULIRGs being grouped together based on the similarity of their spectra. Additionally, we extract and compare physical features from the mid-IR spectra, such as the polycyclic aromatic hydrocarbons (PAHs) emission and silicate depth absorption features, as indicators of the presence of star-forming regions and obscuring dust, in order to understand the underlying physical mechanisms of each evolutionary stage of ULIRGs. Our analysis identifies five groups of local ULIRGs based on their mid-IR spectra, which is quite consistent with the well established fork classification diagram by providing a higher level classification. We demonstrate how graph clustering algorithms and network analysis tools can be utilized as unsupervised learning techniques for revealing direct or indirect relations between various galaxy properties and evolutionary stages, which provides an alternative methodology to previous works for classification in galaxy evolution. Additionally, our methodology compares the output of several graph clustering algorithms in order to demonstrate the best-performing Graph Theoretical tools for studying galaxy evolution.

2.Diffuse emission in microlensed quasars and its implications for accretion-disk physics

Authors:C. Fian, D. Chelouche, S. Kaspi

Abstract: We investigate the discrepancy between the predicted size of accretion disks (ADs) in quasars and the observed sizes as deduced from gravitational microlensing studies. Specifically, we aim to understand whether the discrepancy is due to an inadequacy of current AD models or whether it can be accounted for by the contribution of diffuse broad-line region (BLR) emission to the observed continuum signal. We employed state-of-the-art emission models for quasars and high-resolution microlensing magnification maps and compared the attributes of their magnification-distribution functions to those obtained for pure Shakura-Sunyaev disk models. We tested the validity of our detailed model predictions by examining their agreement with published microlensing estimates of the half-light radius of the continuum-emitting region in a sample of lensed quasars. Our findings suggest that the steep disk temperature profiles found by microlensing studies are erroneous as the data are largely affected by the BLR, which does not obey a temperature-wavelength relation. We show with a sample of 12 lenses that the mere contribution of the BLR to the continuum signal is able to account for the deduced overestimation factors as well as the implied size-wavelength relation. Our study points to a likely solution to the AD size conundrum in lensed quasars, which is related to the interpretation of the observed signals rather than to disk physics. Our findings significantly weaken the tension between AD theory and observations, and suggest that microlensing can provide a new means to probe the hitherto poorly constrained diffuse BLR emission around accreting black holes.

3.Simulated analogues II: a new methodology for non-parametric matching of models to observations

Authors:Rami Al-Belmpeisi, Vito Tuhtan, Mikkel Bregning Christensen, Rajika L Kuruwita, Troels Haugbølle

Abstract: Star formation is a multi-scale problem, and only global simulations that account for the connection from the molecular cloud scale gas flow to the accreting protostar can reflect the observed complexity of protostellar systems. Star-forming regions are characterised by supersonic turbulence and as a result, it is not possible to simultaneously design models that account for the larger environment and in detail reproduce observed stellar systems. Instead, the stellar inventories can be matched statistically, and best matches found that approximate specific observations. Observationally, a combination of single-dish telescopes and interferometers are now able to resolve the nearest protostellar objects on all scales from the protostellar core to the inner 10 AU. We present a new non-parametric methodology which uses high-resolution simulations and post-processing methods to match simulations and observations using deep learning. Our goal is to perform a down-selection from large data sets of synthetic images to a ranked list of best-matching candidates with respect to the observation. This is particularly useful for binary and multiple stellar systems that form in turbulent environments. The objective is to accelerate the rate at which we can do such comparisons, remove biases from hand-picking matches, and contribute to identifying the underlying physical processes that drive the creation and evolution of observed protostellar systems.

4.Simulation-guided galaxy evolution inference: A case study with strong lensing galaxies

Authors:Andreas Filipp, Yiping Shu, Ruediger Pakmor, Sherry H. Suyu, Xiaosheng Huang

Abstract: Understanding the evolution of galaxies provides crucial insights into a broad range of aspects in astrophysics, including structure formation and growth, the nature of dark energy and dark matter, baryonic physics, and more. It is, however, infeasible to track the evolutionary processes of individual galaxies in real time given their long timescales. As a result, galaxy evolution analyses have been mostly based on ensembles of galaxies that are supposed to be from the same population according to usually basic and crude observational criteria. We propose a new strategy of evaluating the evolution of an individual galaxy by identifying its descendant galaxies as guided by cosmological simulations. As a proof of concept, we examined the evolution of the total mass distribution of a target strong lensing galaxy at $z=0.884$ using the proposed strategy. We selected 158 galaxies from the IllustrisTNG300 simulation that we identified as analogs of the target galaxy. We followed their descendants and found 11 observed strong lensing galaxies that match in stellar mass and size with the descendants at their redshifts. The observed and simulated results are discussed, although no conclusive assessment is made given the low statistical significance due to the small sample size. Nevertheless, the test confirms that our proposed strategy is already feasible with existing data and simulations. We expect it to play an even more important role in studying galaxy evolution as more strong lens systems and larger simulations become available with the advent of next-generation survey programs and cosmological simulations.

1.Evolution of Non-parametric Morphology of Galaxies in the JWST CEERS Field at $z\simeq$0.8-3.0

Authors:Yao Yao, Jie Song, Xu Kong, Guanwen Fang, Hong-Xin Zhang, Xinkai Chen

Abstract: Galaxy morphology is one of the most fundamental ways to describe galaxy properties, but the morphology we observe may be affected by wavelength and spatial resolution, which may introduce systematic bias when comparing galaxies at different redshift. Taking advantage of the broad wavelength coverage from optical to near-IR and high resolution NIRCam instrument of JWST, we measure the non-parametric morphological parameters of a total of 1376 galaxies at $z\simeq$0.8-3.0 in the CEERS field through an optimized code called {\tt\string statmorph\_csst}. We divide our sample into three redshift intervals and investigate the wavelength- and redshift-dependence of the morphological parameters. We also explore how the widely-used galaxy type classification methods based on the morphological parameters depend on wavelength and spatial resolution. We find that there are variations in all morphological parameters with rest-frame wavelength ($\lambda_{\rm rf}$), especially at the short wavelength end, and the $\lambda_{\rm rf}$ mainly affects the classification between late-type and early-type galaxy. As the $\lambda_{\rm rf}$ increases, the galaxies on the $G-M_{20}$ diagram move to the upper left with a slope of -0.23$\pm$0.03 on average. We find that spatial resolution mainly affects the merger identification. The merger fraction in F200W resolution can be $\ga$2 times larger than that in F444W resolution. Furthermore, We compare the morphological parameter evolution of galaxies with different stellar masses. We find that there are differences in the morphological evolution of high- and low-mass (log$M_*\geqslant$10 and 9$<$log$M_*<$10) galaxies in the studied redshift range, which may be caused by their different evolution paths.

2.Distributions of the Density and Kinetic Temperature of the Molecular Gas in the Central Region of NGC 613 using Hierarchical Bayesian Inference

Authors:Hiroyuki Kaneko, Tomoka Tosaki, Kunihiko Tanaka, Yusuke Miyamoto

Abstract: We present position-position-velocity (PPV) cubes of the physical and chemical properties of the molecular medium in the central 1.2 kpc region of the active galaxy NGC 613 at a PPV resolution of 0.$^{\prime\prime}$8$\times$0.$^{\prime\prime}$8$\times$10 km s$^{-1}$ (0.$^{\prime\prime}$8 = $\sim$68 pc). We used eight molecular lines obtained with ALMA. Non-LTE calculation with hierarchical Bayesian inference was used to construct PPV cubes of the gas kinetic temperature ($T_\mathrm{kin}$), molecular hydrogen volume density ($n_\mathrm{H_2}$), column densities ($N_\mathrm{H_2}$), and fractional abundances of four molecules ($^{12}$C$^{18}$O, HCN, HCO$^+$, and CS). The derived $n_\mathrm{H_2}$, $N_\mathrm{H_2}$, and $T_\mathrm{kin}$ ranged 10$^{3.21-3.85}$ cm$^{-3}$, 10$^{20.8-22.1}$ cm$^{-2}$, and 10$^{2.33-2.64}$ K, respectively. Our first application of the non-LTE method with the hierarchical Bayesian inference to external galaxies yielded compatible results compared with the previous studies of this galaxy, demonstrating the efficacy of this method for application to other galaxies. We examined the correlation between gas surface density $\Sigma_\mathrm{H_2}$ (converted from $N_\mathrm{H_2}$) and the star formation rate $\Sigma_\mathrm{SFR}$ obtained from the 110 GHz continuum flux map and found two distinct sequences in the $\Sigma_\mathrm{H_2}$-$\Sigma_\mathrm{SFR}$ diagram; the southwestern subregion of the star-forming ring exhibited a $\sim$0.5 dex higher star formation efficiency (SFE; $\Sigma_\mathrm{SFR}/\Sigma_\mathrm{H_2}$) than the eastern subregion. However, they exhibited no systematic difference in $n_\mathrm{H_2}$, which is often argued as a driver of SFE variation. We suggest that the deficiency of molecular gas in the southwestern subregion, where no significant gas supply is evident along the offset ridges in the bar, is responsible for the elevated SFE.

3.Minor merger growth in action: JWST detects faint blue companions around massive quiescent galaxies at 0.5 < z < 3

Authors:Katherine A. Suess, Christina C. Williams, Brant Robertson, Zhiyuan Ji, Benjamin D. Johnson, Erica Nelson, Stacey Alberts, Kevin Hainline, Francesco DEugenio, Hannah Ubler, Marcia Rieke, George Rieke, Andrew J. Bunker, Stefano Carniani, Stephane Charlot, Daniel J. Eisenstein, Roberto Maiolino, Daniel P. Stark, Sandro Tacchella, Chris Willott

Abstract: Minor mergers are thought to drive the structural evolution of massive quiescent galaxies; however, existing HST imaging is primarily sensitive to stellar mass ratios >1:10. Here, we report the discovery of a large population of low-mass companions within 35 kpc of known logM*/Msun > 10.5 quiescent galaxies at 0.5 < z < 3. While massive companions like those identified by HST are rare, JWST imaging from JADES reveals that the average massive quiescent galaxy hosts ~5 nearby companions with stellar mass ratios <1:10. Despite a median stellar mass ratio of just 1:900, these tiny companions are so numerous that they represent at least 30\% of the total mass being added to quiescent galaxies via minor mergers. While relatively massive companions have colors similar to their hosts, companions with mass ratios <1:10 typically have bluer colors and lower mass-to-light ratios than their host galaxies at similar radii. The accretion of these tiny companions is likely to drive evolution in the color gradients and stellar population properties of the host galaxies. Our results suggest that the well-established ``minor merger growth" model for quiescent galaxies extends down to very low mass ratios of <1:100, and demonstrates the power of JWST to constrain both the spatially-resolved properties of massive galaxies and the properties of low-mass companions beyond the local universe.

4.Revealing the Gas Recycling in the Circumgalactic Medium (CGM) Utilizing a Luminous Ly$α$ Nebula Around a Type-II Quasar at z=2.6 with the Keck Cosmic Web Imager (KCWI)

Authors:Shiwu Zhang, Zheng Cai, Dandan Xu, Andrea Afruni, Yunjing Wu, Wuji Wang, Fabrizio Arrigoni Battaia, Mingyu Li, Sen Wang, Xianzhi Bi

Abstract: How galaxies acquire material from the circumgalactic medium (CGM) is a key question in galaxy evolution. Recent observations and simulations show that gas recycling could be an important avenue for star formation. This paper presents Keck Cosmic Web Imager (KCWI) integral field unit spectroscopic observations on a type-II quasar, Q1517+0055 at z = 2.65, a pilot study of our Ly${\alpha}$ nebulae sample at $z\approx 2$. We revealed diffuse emission of the Ly$\alpha$ 1216, HeII 1640, and CIV 1549 on the projected physical scale of 122 kpc, 45 kpc, and 79 kpc, respectively. The total Ly$\alpha$ luminosity is L$_{\rm Ly\alpha}$ = $3.04\pm 0.02 \times 10^{44}$ erg s$^{-1}$. The line ratio diagnostics shows that HeII/Ly$\alpha$ $\approx$0.08 and CIV/Ly$\alpha$ $\approx$0.28, consistent with the photoionization including recombination and photon pumping. We also identify the associated HI and CIV absorption from the spectra. By fitting the spectra, we derive both the column density and the velocity. We find that the velocity profile from both the absorption and the HeII emission exhibit increasing trends. Moreover, both the line ratio diagnostic from the emission and the column density ratio from the absorption confirm that the cool gas metallicity is $\geq Z_{\odot}$. From detailed modeling and estimation, gas recycling might be a more plausible interpretation compared with the scenario of a powerful outflow.

5.The nature of the X-ray sources in dwarf galaxies in nearby clusters from the KIWICS

Authors:Şeyda Şen, Ersin Göğüş, Reynier F. Peletier, Nelvy Choque-Challapa, Amirnezam Amiri

Abstract: We present a deep search for and analysis of X-ray sources in a sample of dwarf galaxies (M$_{r}$ < -15.5 mag) located within twelve galaxy clusters from the Kapteyn IAC WEAVE INT Cluster Survey (KIWICS) of photometric observations in the $\textit{r}$ and $\textit{g}$ using the Wide Field Camera (WFC) at the 2.5-m Isaac Newton telescope (INT). We first investigated the optical data, identified 2720 dwarf galaxies in all fields and determined their characteristics; namely, their colors, effective radii, and stellar masses. We then searched the $\textit{Chandra}$ data archive for X-ray counterparts of optically detected dwarf galaxies. We found a total of 20 X-ray emitting dwarf galaxies, with X-ray flux ranging from 1.7$\times10^{-15}$ to 4.1$\times10^{-14}$ erg cm$^{-2}$ s$^{-1}$ and X-ray luminosities varying from 2$\times10^{39}$ to 5.4$\times10^{41}$ erg s$^{-1}$. Our results indicate that the X-ray luminosity of the sources in our sample is larger than the Eddington luminosity limit for a typical neutron star, even at the lowest observed levels. This leads us to conclude that the sources emitting X-rays in our sample are likely black holes. Additionally, we have employed a scaling relation between black hole and stellar mass to estimate the masses of the black holes in our sample, and have determined a range of black hole masses from 4.6$\times10^{4}$ to 1.5$\times10^{6}$ M$_\odot$. Finally, we find a trend between X-ray to optical flux ratio and X-ray flux. We discuss the implications of our findings and highlight the importance of X-ray observations in studying the properties of dwarf galaxies.

6.HINOTORI I: The Nature of Rejuvenation Galaxies

Authors:Takumi S. Tanaka, Kazuhiro Shimasaku, Sandro Tacchella, Makoto Ando, Kei Ito, Hassen M. Yesuf, Suin Matsui

Abstract: We present the HINOTORI (star formation History INvestigatiOn TO find RejuvenatIon) project to reveal the nature of rejuvenation galaxies (RGs), which are galaxies that restarted their star formation after being quiescent. As the first step of HINOTORI, we construct the largest RG sample with 1071 sources. We select these RGs from 8857 MaNGA (Mapping Nearby Galaxies at APO) survey galaxies by reconstructing their star formation histories with Prospector spectral energy distribution fitting code. Both optical spectral data and UV to IR photometric data are used for the fitting. Using mock data, we confirm that our method can detect weak rejuvenation events that form only about 0.1% of the total stellar mass with high completeness. The RGs account for ~10% of the whole sample, and rejuvenation events contribute on average only about 0.1% of the total stellar mass in those galaxies but 17% of the cosmic-star formation rate density today. Our RGs have a similar mass distribution to quiescent galaxies (QGs). However, the morphology of the RGs is more disk-like than QGs, suggesting that rejuvenation may occur selectively in disk-like QGs. Our results also suggest the possibility of multiple-time rejuvenation events in a single galaxy. Further spatially resolved analyses of integral field unit data and radio observations and comparisons to simulations are needed to identify the mechanism and the role of rejuvenation in galaxy evolution.

7.Flow of gas detected from beyond the filaments to protostellar scales in Barnard 5

Authors:M. T. Valdivia-Mena, J. E. Pineda, D. M. Segura-Cox, P. Caselli, A. Schmiedeke, S. Choudhury, S. S. R. Offner, R. Neri, A. Goodman, G. A. Fuller

Abstract: Infall of gas from outside natal cores has proven to feed protostars after the main accretion phase (Class 0). This changes our view of star formation to a picture that includes asymmetric accretion (streamers), and a larger role of the environment. However, the connection between streamers and the filaments that prevail in star-forming regions is unknown. We investigate the flow of material toward the filaments within Barnard 5 (B5) and the infall from the envelope to the protostellar disk of the embedded protostar B5-IRS1. Our goal is to follow the flow of material from the larger, dense core scale, to the protostellar disk scale. We present new HC$_3$N line data from the NOEMA and 30m telescopes covering the coherence zone of B5, together with ALMA H$_2$CO and C$^{18}$O maps toward the protostellar envelope. We fit multiple Gaussian components to the lines so as to decompose their individual physical components. We investigate the HC$_3$N velocity gradients to determine the direction of chemically-fresh gas flow. At envelope scales, we use a clustering algorithm to disentangle the different kinematic components within H$_2$CO emission. At dense core scales, HC$_3$N traces the infall from the B5 region toward the filaments. HC$_3$N velocity gradients are consistent with accretion toward the filament spines plus flow along them. We found a $\sim2800$ au streamer in H$_2$CO emission which is blueshifted with respect to the protostar and deposits gas at outer disk scales. The strongest velocity gradients at large scales curve toward the position of the streamer at small scales, suggesting a connection between both flows. Our analysis suggests that the gas can flow from the dense core to the protostar. This implies that the mass available for a protostar is not limited to its envelope, and can receiving chemically-unprocessed gas after the main accretion phase.

8.The Magellanic Puzzle: origin of the periphery

Authors:Pol Massana Montana State University, David L. Nidever Montana State University, Knut Olsen NSF's National Optical-Infrared Astronomy Research Laboratory

Abstract: In this paper, we analyse the metallicity structure of the Magellanic Clouds using parameters derived from the Gaia DR3 low-resolution XP spectra, astrometry and photometry. We find that the qualitative behavior of the radial metallicity gradients in the LMC and SMC are quite similar, with both of them having a metallicity plateau at intermediate radii and a second at larger radii. The LMC has a first metallicity plateau at [Fe/H]$\approx$-0.8 for 3$-$7\degr, while the SMC has one at [Fe/H]$\approx$-1.1 at 3$-$5\degr. The outer LMC periphery has a fairly constant metallicity of [Fe/H]$\approx$-1.0 (10$-$18\degr), while the outer SMC periphery has a value of [Fe/H]$\approx$-1.3 (6$-$10\degr). The sharp drop in metallicity in the LMC at $\sim$8\dgr and the marked difference in age distributions in these two regions suggests that there were two important evolutionary phases in the LMC. In addition, we find that the Magellanic periphery substructures, likely Magellanic debris, are mostly dominated by LMC material stripped off in old interactions with the SMC. This presents a new picture in contrast with the popular belief that the debris around the Clouds had been mostly stripped off from the SMC due to having a lower mass. We perform a detailed analysis for each known substructure and identify its potential origin based on metallicities and motions with respect to each galaxy.

1.Evidence for low power radio jet-ISM interaction at 10 parsec in the dwarf AGN host NGC 4395

Authors:Payel Nandi, C. S. Stalin, D. J. Saikia, Rogemar A. Riffel, Arijit Manna, Sabyasachi Pal, O. L. Dors, Dominika Wylezalek, Vaidehi S. Paliya, P. Saikia, Pratik Dabhade, Markus-Kissler Patig, Ram Sagar

Abstract: Black hole driven outfBlack hole driven outflows in galaxies hosting active galactic nuclei (AGN) may interact with their interstellar medium (ISM) affecting star formation. Such feedback processes, reminiscent of those seen in massive galaxies, have been reported recently in some dwarf galaxies. However, such studies have usually been on kiloparsec and larger scales and our knowledge on the smallest spatial scales to which this feedback processes can operate is unclear. Here we demonstrate radio jet-ISM interaction on the scale of an asymmetric triple radio structure of $\sim$10 parsec size in NGC 4395. This triplet radio structure is seen in the 15 GHz continuum image and the two asymmetric jet like structures are situated on either side of the radio core that coincides with the optical {\it Gaia} position. The high resolution radio image and the extended [OIII]$\lambda$5007 emission, indicative of an outflow, are spatially coincident and are consistent with the interpretation of a low power radio jet interacting with the ISM. Modelling of the spectral lines using CLOUDY and MAPPINGS, and estimation of temperature using Gemini and MaNGA integral field spectroscopic data suggest shock ionization of the gas. The continuum emission at 237 GHz, though weak was found to spatially coincide with the AGN, however, the CO(2-1) line emission was found to be displaced by around 1 arcsec northward of the AGN core. The spatial coincidence of molecular H2$\lambda$2.4085 along the jet direction, the morphology of ionised [OIII]$\lambda$5007 and displacement of CO(2-1) emission argues for conditions less favourable for star formation at $\sim$5 parsec.

2.Concluding remarks: Faraday Discussion on astrochemistry at high resolution

Authors:T. J. Millar

Abstract: Fifty years on from the first detailed chemical kinetic modelling of astronomical sources, I provide some introductory comments on the history of astrochemistry, summarise some personal views on the topics covered in this discussion meeting, and conclude with some thoughts on its future development. I have left out the jokes.

3.Stellar angular momentum of disk galaxies at z = 0.7 in the MAGIC survey I. Impact of the environment

Authors:W. Mercier, B. Epinat, T. Contini, D. Krajnović, L. Ciesla, B. C. Lemaux, V. Abril-Melgarejo, L. Boogaard, D. Pelliccia

Abstract: Aims: At intermediate redshift, galaxy groups/clusters are thought to impact galaxies (e.g. their angular momentum). We investigate whether the environment has an impact on the galaxies' angular momentum and identify underlying driving physical mechanisms. Methods: We derive robust estimates of the stellar angular momentum using Hubble Space Telescope (HST) images combined with spatially resolved ionised gas kinematics from the Multi-Unit Spectroscopic Explorer (MUSE) for a sample of ~200 galaxies in groups and in the field at z~0.7 drawn from the MAGIC survey. Using various environmental tracers, we study the position of the galaxies in the the angular momentum-stellar mass (Fall) relation as a function of environment. Results: We measure a 0.12 dex (2sigma significant) depletion of angular momentum for low-mass galaxies (M* < 10^10 Msun) in groups with respect to the field. Massive galaxies located in dense environments have less angular momentum than expected from the low-mass Fall relation but, without a comparable field sample, we cannot infer whether this effect is mass- or environmentally-driven. Furthermore, massive galaxies are found in the centre of the structures and have low systemic velocities. The observed depletion of angular momentum at low mass does not appear linked with the strength of the over-density around the galaxies but it is strongly correlated with the galaxies' systemic velocity normalised by the dispersion of their host group and with their ionised gas velocity dispersion. Conclusions: Group galaxies seem depleted in angular momentum, especially at low mass. Our results suggest that this depletion might be induced by physical mechanisms that scale with the systemic velocity of the galaxies (e.g. stripping or merging) and that such mechanism might be responsible for enhancing the velocity dispersion of the gas as galaxies lose angular momentum.

4.The minimum measurable eccentricity from gravitational waves of LISA massive black hole binaries

Authors:Mudit Garg, Shubhanshu Tiwari, Andrea Derdzinski, John Baker, Sylvain Marsat, Lucio Mayer

Abstract: We explore the eccentricity measurement threshold of LISA for gravitational waves radiated by massive black hole binaries (MBHBs) with redshifted BH masses $M_z$ in the range $10^{4.5}\mbox{-}10^{7.5}~{\rm M}_\odot$ at redshift $z=1$. The eccentricity can be an important tracer of the environment where MBHBs evolve to reach the merger phase. To consider LISA's motion and apply the time delay interferometry, we employ the lisabeta software and produce year-long eccentric waveforms using the inspiral-only post-Newtonian model TaylorF2Ecc. We study the minimum measurable eccentricity ($e_{\rm min}$, defined at one year before the merger) analytically by computing matches and Fisher matrices, and numerically via Bayesian inference by varying both intrinsic and extrinsic parameters. We find that $e_{\rm min}$ has a strong dependence on $M_z$ and a weak dependence on mass ratio and extrinsic parameters. Match-based signal-to-noise ratio criterion suggest that LISA will be able to detect $e_{\rm min}\sim10^{-2.5}$ for lighter systems ($M_z\lesssim10^{5.5}~{\rm M}_\odot$) and $\sim10^{-1.5}$ for heavier MBHBs with a $90\%$ confidence. Bayesian inference with Fisher initialization and a zero noise realization pushes this limit to $e_{\rm min}\sim10^{-2.75}$ for lower-mass binaries assuming a $<50\%$ relative error. Bayesian inference can recover injected eccentricities of $0.1$ and $10^{-2.75}$ for a $10^5~{\rm M}_\odot$ system with a $\sim10^{-2}\%$ and a $\sim10\%$ relative errors, respectively. Both analytical and numerical methodologies provide almost consistent results for our systems of interest. LISA will launch in a decade, making this study valuable and timely to prepare for unlocking the mysteries of the MBHB evolution.

5.The missing radial velocities of Gaia: a catalogue of Bayesian estimates for DR3

Authors:Aneesh P. Naik, Axel Widmark

Abstract: In an earlier work, we demonstrated the effectiveness of Bayesian neural networks in estimating the missing line-of-sight velocities of Gaia stars, and published an accompanying catalogue of blind predictions for the line-of-sight velocities of stars in Gaia DR3. These were not merely point predictions, but probability distributions reflecting our state of knowledge about each star. Here, we verify that these predictions were highly accurate: the DR3 measurements were statistically consistent with our prediction distributions, with an approximate error rate of 1.5%. We use this same technique to produce a publicly available catalogue of predictive probability distributions for the 185 million stars up to a G-band magnitude of 17.5 still missing line-of-sight velocities in Gaia DR3. Validation tests demonstrate that the predictions are reliable for stars within approximately 7 kpc from the Sun and with distance precisions better than around 20%. For such stars, the typical prediction uncertainty is 25-30 km/s. We invite the community to use these radial velocities in analyses of stellar kinematics and dynamics, and give an example of such an application.

6.Mapping gravity in stellar nurseries -- establishing the effectiveness of 2D acceleration maps

Authors:Zhen-Zhen He, Guang-Xing Li, Andreas Burkert

Abstract: Gravity is the driving force of star formation. Although gravity is caused by the presence of matter, its role in complex regions is still unsettled. One effective way to study the pattern of gravity is to compute the accretion it exerts on the gas by providing gravitational acceleration maps. A practical way to study acceleration is by computing it using 2D surface density maps, yet whether these maps are accurate remains uncertain. Using numerical simulations, we confirm that the accuracy of the acceleration maps $\mathbf a_{\rm 2D}(x,y)$ computed from 2D surface density are good representations for the mean acceleration weighted by mass. Due to the under-estimations of the distances from projected maps, the magnitudes of accelerations will be over-estimated $|\mathbf a_{\rm 2D}(x,y)| \approx 2.3 \pm 1.8 \; |\mathbf a_{\rm 3D}^{\rm proj}(x,y)|$, where $\mathbf a_{\rm 3D}^{\rm proj}(x,y)$ is mass-weighted projected gravitational acceleration, yet $\mathbf a_{\rm 2D}(x,y)$ and $ \mathbf a_{\rm 3D}^{\rm proj}(x,y)$ stay aligned within 20$^{\circ}$. Significant deviations only occur in regions where multiple structures are present along the line of sight. The acceleration maps estimated from surface density provide good descriptions of the projection of 3D acceleration fields. We expect this technique useful in establishing the link between cloud morphology and star formation, and in understanding the link between gravity and other processes such as the magnetic field. A version of the code for calculating surface density gravitational potential is available at \url{}.

7.Panchromatic Photometry of Low-redshift, Massive Galaxies Selected from SDSS Stripe 82

Authors:Yang A. Li, Luis C. Ho, Jinyi Shangguan, Ming-Yang Zhuang, Ruancun Li

Abstract: The broadband spectral energy distribution of a galaxy encodes valuable information on its stellar mass, star formation rate (SFR), dust content, and possible fractional energy contribution from nonstellar sources. We present a comprehensive catalog of panchromatic photometry, covering 17 bands from the far-ultraviolet to 500 $\mu$m, for 2685 low-redshift (z=0.01-0.11), massive ($M_* > 10^{10}\,M_\odot$) galaxies selected from the Stripe 82 region of the Sloan Digital Sky Survey, one of the largest areas with relatively deep, uniform observations over a wide range of wavelengths. Taking advantage of the deep optical coadded images, we develop a hybrid approach for matched-aperture photometry of the multi-band data. We derive robust uncertainties and upper limits for undetected galaxies, deblend interacting/merging galaxies and sources in crowded regions, and treat contamination by foreground stars. We perform spectral energy distribution fitting to derive the stellar mass, SFR, and dust mass, critically assessing the influence of flux upper limits for undetected photometric bands and applying corrections for systematic uncertainties based on extensive mock tests. Comparison of our measurements with those of commonly used published catalogs reveals good agreement for the stellar masses. While the SFRs of galaxies on the star-forming main sequence show reasonable consistency, galaxies in and below the green valley show considerable disagreement between different sets of measurements. Our analysis suggests that one should incorporate the most accurate and inclusive photometry into the spectral energy distribution analysis, and that care should be exercised in interpreting the SFRs of galaxies with moderate to weak star formation activity.

8.The Subtle Effects of Mergers on Star Formation in Nearby Galaxies

Authors:Yang A. Li, Luis C. Ho, Jinyi Shangguan

Abstract: Interactions and mergers play an important role in regulating the physical properties of galaxies, such as their morphology, gas content, and star formation rate (SFR). Controversy exists as to the degree to which these events, even gas-rich major mergers, enhance star formation activity. We study merger pairs selected from a sample of massive ($M_* \ge 10^{10}\,M_\odot$), low-redshift ($z = 0.01-0.11$) galaxies located in the Stripe 82 region of the Sloan Digital Sky Survey, using stellar masses, SFRs, and total dust masses derived from a new set of uniformly measured panchromatic photometry and spectral energy distribution analysis. The dust masses, when converted to equivalent total atomic and molecular hydrogen, probe gas masses as low as $\sim 10^{8.5}\,M_\odot$. Our measurements delineate a bimodal distribution on the $M_{\rm gas}-M_*$ plane: the gas-rich, star-forming galaxies that trace the well-studied gas mass main sequence, and passive galaxies that occupy a distinct, gas-poor regime. These two populations, in turn, map into a bimodal distribution on the relation between SFR and gas mass surface density. Among low-redshift galaxies, galaxy mergers, including those that involve gas-rich and nearly equal-mass galaxies, exert a minimal impact on their SFR, specific SFR, or star formation efficiency. Starbursts are rare. The star formation efficiency of gas-rich, minor mergers even appears suppressed. This study stresses the multiple, complex factors that influence the evolution of the gas and its ability to form stars in mergers.

9.The radio emission in radio-quiet quasars: the VLBA perspective

Authors:Sina Chen, Ari Laor, Ehud Behar, Ranieri D. Baldi, Joseph D. Gelfand

Abstract: The origin of the radio emission in radio-quiet quasars (RQQ) is not established yet. We present new VLBA observations at 1.6 and 4.9 GHz of ten RQQ (nine detected), which together with published earlier observations of eight RQQ (five detected), forms a representative sample of 18 RQQ drawn from the Palomar-Green sample of low z (< 0.5) AGN. The spectral slope of the integrated emission extends from very steep (alpha < -1.98) to strongly inverted (alpha = +2.18), and the slopes of nine of the 14 objects are flat (alpha > -0.5). Most objects have an unresolved flat-spectrum core, which coincides with the optical Gaia position. The extended emission is generally steep-spectrum, has a low brightness temperature (< 10^7 K), and is displaced from the optical core (the Gaia position) by ~ 5-100 pc. The VLBA core flux is tightly correlated with the X-ray flux, and follows a radio to X-ray luminosity relation of log L_R/L_X = -6, for all objects with a black hole mass log M_BH/M_Sun < 8.5. The flatness of the core emission implies a compact source size (< 0.1 pc), which likely originates from the accretion disk corona. The mas-scale extended emission is optically thin and of clumpy structure, and is likely produced by an outflow from the center. Radio observations at higher frequencies can further test the accretion disk coronal emission interpretation for the core emission in RQQ.

10.Internal kinematics of dwarf satellites of MW/M31-like galaxies in TNG50

Authors:Alberto Manuel Martínez-García, Andrés del Pino, Ewa L. Łokas, Roeland P. van der Marel, Antonio Aparicio

Abstract: We present a kinematic study of a thousand of dwarf satellites of MW/M31-like hosts from the IllustrisTNG50 simulation. Internal kinematics were derived for all the snapshots to obtain a historical record of their rotation velocity in the plane of the sky ($|V_T|$) and the amplitude of their velocity gradients along the line of sight ($A_{\rm grad}^{v_z}$) measured from the host. For the majority of the satellites we initially detected rotation in the plane of the sky (65%) or velocity gradients (80%), and this was progressively reduced to 45% and 68% at $z = 0$ respectively. We find that the evolution of the rotation in the plane of the sky and the velocity gradients differs according to type of dwarfs, which could be explained in terms of their different masses and orbital histories. We observe that interaction with the host has an impact on the evolution of the internal kinematics of the satellites. The rotation signal of the satellites is progressively reduced during pericentric passages, the first pericentre being especially disruptive for the initial kinematics. We observe temporary increases in $A_{\rm grad}^{v_z}$ during pericentric passage caused by tidal interaction with the host, $A_{\rm grad}^{v_z}$ increasing as the satellites approach their pericentre and dropping as they move away. In summary, we conclude that the presence of detectable rotation in dwarf satellites is not uncommon, and that the evolution of their internal kinematics is clearly affected by their interaction with the host.

1.Identifying the disc, bulge, and intra-halo light of simulated galaxies through structural decomposition

Authors:Katy L. Proctor, Claudia del P. Lagos, Aaron D. Ludlow, Aaron S. G. Robotham

Abstract: We perform a structural decomposition of galaxies identified in three cosmological hydrodynamical simulations by applying Gaussian Mixture Models (GMMs) to the kinematics of their stellar particles. We study the resulting disc, bulge, and intra-halo light (IHL) components of galaxies whose host dark matter haloes have virial masses in the range $M_{200}=10^{11}$-- $10^{15}\,{\rm M_\odot}$. Our decomposition technique isolates galactic discs whose mass fractions, $f_{\rm disc}$, correlate strongly with common alternative morphology indicators; for example, $f_{\rm disc}$ is approximately equal to $\kappa_{{\rm co}}$, the fraction of stellar kinetic energy in co-rotation. The primary aim of our study, however, is to characterise the IHL of galaxies in a consistent manner and over a broad mass range, and to analyse its properties from the scale of galactic stellar haloes up to the intra-cluster light. Our results imply that the IHL fraction, $f_{\rm IHL}$, has appreciable scatter and is strongly correlated with galaxy morphology: at fixed stellar mass, the IHL of disc galaxies is typically older and less massive than that of spheroids. Above $M_{200}\approx 10^{13}\,{\rm M_\odot}$, we find, on average, $f_{\rm IHL}\approx 0.45$, albeit with considerable scatter. The transition radius beyond which the IHL dominates the stellar mass of a galaxy is roughly $30\,{\rm kpc}$ for $M_{200}\lesssim 10^{12.8}\,{\rm M_\odot}$, but increases strongly towards higher masses. However, we find that no alternative IHL definitions -- whether based on the ex-situ stellar fraction, or the stellar mass outside a spherical aperture -- reproduce our dynamically-defined IHL fractions.

2.Astrometric mass measurement of compact companions in binary systems with Gaia

Authors:Yilun Wang, Shilong Liao, Nicola Giacobbo, Aleksandra Olejak, Jian Gao, Jifeng Liu

Abstract: For binary systems with an unseen primary and a luminous secondary, the astrometric wobble of the secondary could be used to study the primary. With Gaia, it is possible to measure the mass of the black hole or neutron star with a luminous companion (hereafter BH/NS-LC). Our aim is to provide a method for predicting Gaia's ability in measuring the mass of BH/NS-LCs. We also tried to estimate the number of solvable BH/NS-LCs using Gaia. We used a realistic Markov chain Monte Carlo simulation of mock Gaia observations to obtain a relation between the uncertainty of mass measurement of the primary in BH/NS-LCs with the observable variables of the secondary astrometric orbit. Furthermore, we used the MOBSE code to evolve a Galactic BH/NS-LC sample with a combined Milky Way model. Our relation is applied to this sample to estimate the number of solvable BH/NS-LCs. We derived a good relation between the mass uncertainty and the binary parameters. For the first time, we show the quantitive influence of the period P, inclination i, eccentricity e, and ecliptic latitude $\beta$ to the mass measurement. Our results suggest that $48^{+7}_{-7}$ BH-LCs and $102^{+11}_{10}$ NS-LCs are solvable during a 5 yr Gaia mission. We also give the distribution of the distance and apparent magnitude of the Gaia solvable BH/NS-LCs. This solvable sample would be increased by additional spectroscopic data or a prolonged Gaia mission. The mass uncertainty relation could be used in future simulations of BH/NS-LCs observed by Gaia. The prediction of the solvable BH/NS-LCs is not only influenced by the process in generating the Galactic BH/NS-LC sample, but is also affected by our uncertainty relation. In particular, the relations of parameters such as $[P, e, i, \beta]$ are very useful to correct the selection effect in the statistic results of the future BH/NS-LC sample observed by Gaia.

1.Spectropolarimetry of Type II supernovae (I) Sample, observational data and interstellar polarization

Authors:T. Nagao, S. Mattila, R. Kotak, H. Kuncarayakti

Abstract: We investigate polarization spectra of hydrogen-rich core-collapse supernovae (Type~II SNe). The polarization signal from SNe contains two independent components: intrinsic SN polarization and interstellar polarization (ISP). From these components, we can study the SN explosion geometry and the dust properties in their host galaxies or in the Milky Way. In this first paper, using a new improved method, we investigate the properties of the ISP components of 11 well-observed Type~II SNe. As a result of our analysis, we find that 10 out of these 11 SNe showed a steady ISP component with a polarization degree $\lesssim 1.0$ \%, while one SN was consistent with zero ISP. As for the wavelength dependence, SN~2001dh (and possibly SN~2012aw) showed a non-Milky-Way-like ISP likely originating from the interstellar dust in their respective host galaxies: their polarization maxima were located at short wavelengths ($\lesssim4000$~\AA). Similar results have been obtained previously for highly reddened SNe. The majority of the SNe in our sample had too large uncertainties in the wavelength dependence of their ISP components to consider them further. Our work demonstrates that, by applying this method to a larger SN sample, further investigation of the ISP component of the SN polarization can provide new opportunities to study interstellar dust properties in external galaxies.

2.Mapping the stellar population and gas excitation of MaNGA galaxies with MEGACUBES. Results for AGN versus control sample

Authors:Rogério Riffel, Nicolas D. Mallmann, Sandro B. Rembold, Gabriele S. Ilha, Rogemar A. Riffel, Thaisa Storchi-Bergmann, Daniel Ruschel-Dutra, Alexandre Vazdekis, Ignacio Martín-Navarro, Jaderson S. Schimoia, Cristina Ramos Almeida, Luiz N. da Costa, Glauber C. Vila-Verde, Lara Gatto

Abstract: We present spaxel-by-spaxel stellar population fits for the $\sim$10 thousand MaNGA datacubes. We provide multiple extension fits files, nominated as MEGACUBES, with maps of several properties as well as emission-line profiles that are provided for each spaxel. All the MEGACUBES are available through a web interface ( or We also defined a final Active Galactic Nuclei (AGN) sample, as well as a control sample matching the AGN host galaxy properties. We have analysed the stellar populations and spatially resolved emission-line diagnostic diagrams of these AGNs and compared them with the control galaxies sample. We find that the relative fractions of young ($t \leq $56 Myr) and intermediate-age (100 Myr $\leq t \leq$ 2 Gyr) show predominantly a positive gradient for both AGNs and controls. The relative fraction of intermediate-age stellar population is higher in AGN hosts when compared to the control sample, and this difference becomes larger for higher [O III] luminosity AGNs. We attribute this to the fact that extra gas is available in these more luminous sources and that it most likely originates from mass-loss from the intermediate-age stars. The spatially resolved diagnostic diagrams reveal that the AGN emission is concentrated in the inner 0.5 $R_e$ (effective radius) region of the galaxies, showing that the AGN classification is aperture dependent and that emission-line ratios have to be taken together with the H$\alpha$ equivalent width for proper activity classification. We present a composite "BPT+WHAN" diagram that produces a more comprehensive mapping of the gas excitation.

3.First glycine isomer detected in the interstellar medium: glycolamide (NH$_2$C(O)CH$_2$OH)

Authors:Víctor M. Rivilla, Miguel Sanz-Novo, Izaskun Jiménez-Serra, Jesús Martín-Pintado, Laura Colzi, Shaoshan Zeng, Andrés Megías, Álvaro López-Gallifa, Antonio Martínez-Henares, Sarah Massalkhi, Belén Tercero, Pablo de Vicente, Sergio Martín, David San Andríes, Miguel A. Requena-Torres, José Luis Alonso

Abstract: We report the first detection in the interstellar medium of a C$_2$H$_5$O$_2$N isomer: $syn$-glycolamide (NH$_2$C(O)CH$_2$OH). The exquisite sensitivity at sub-mK levels of an ultra-deep spectral survey carried out with the Yebes 40m and IRAM 30m telescopes towards the G+0.693-0.027 molecular cloud have allowed us to unambiguously identify multiple transitions of this species. We derived a column density of (7.4 $\pm$ 0.7)$\times$10$^{12}$ cm$^{-2}$, which implies a molecular abundance with respect to H$_2$ of 5.5$\times$10$^{-11}$. The other C$_2$H$_5$O$_2$N isomers, including the higher-energy $anti$ conformer of glycolamide, and two conformers of glycine, were not detected. The upper limit derived for the abundance of glycine indicates that this amino acid is surely less abundant than its isomer glycolamide in the ISM. The abundances of the C$_2$H$_5$O$_2$N isomers cannot be explained in terms of thermodynamic equilibrium, and thus chemical kinetics need to be invoked. While the low abundance of glycine might not be surprising, based on the relative low abundances of acids in the ISM compared to other compounds (e.g. alcohols, aldehydes or amines), several chemical pathways can favour the formation of its isomer glycolamide. It can be formed through radical-radical reactions on the surface of dust grains. The abundances of these radicals can be significantly boosted in an environment affected by a strong ultraviolet field induced by cosmic rays, such as that expected in G+0.693-0.027. Therefore, as shown by several recent molecular detections towards this molecular cloud, it stands out as the best target to discover new species with carbon, oxygen and nitrogen with increasing chemical complexity.

4.The impact of supernova feedback on the mass-metallicity relations

Authors:Dyna Ibrahim, Chiaki Kobayashi

Abstract: Metallicity is a fundamental physical property that strongly constrains galaxy formation and evolution. The formation of stars in galaxies is suppressed by the energy released from supernova explosions and can be enhanced by metal production. In order to understand the impact of this supernova feedback, we compare four different feedback methods, ejecting energy in thermal, kinetic, stochastic and mechanical forms, into our self-consistent cosmological chemodynamical simulations. To minimise other uncertainties, we use the latest nucleosynthesis yields that can reproduce the observed elemental abundances of stars in the Milky Way. For each method, we predict the evolution of stellar and gas-phase metallicities as a function of galaxy mass, i.e., the mass-metallicity relations. We then find that the mechanical feedback can give the best match to a number of observations up to redshift $z\sim3$, although the predicted gas-phase metallicities seem to be higher than observed at $z\ge 1$. The feedback modelling can be further constrained by the metallicities in distant galaxies with the James Web Space Telescope and those of a large sample with ongoing and future spectroscopic surveys.

5.AGN's Deadness Over Cosmic Time: UVJ Diagrams of X-Ray-Selected AGN

Authors:Rachel Cionitti, Brandon Coleman, Allison Kirkpatrick, Greg Troiani

Abstract: Active Galactic Nuclei (AGN) are intensely accreting supermassive black holes at the centers of massive galaxies. Though these objects occupy little spatial extent of the galaxy itself, they are thought to have far reaching affects, impacting the galaxy's star formation, and possibly it's lifespan until it becomes 'red and dead'. Typical galaxies demonstrate that, over cosmic time, they tend to separate into a bimodal distribution of 'red and dead' or blue and star forming. We examine whether active galaxies evolve over cosmic time in a similar way, and whether this can reveal anything about the complexities of the relationship between an AGN and the host galaxy. We use the Stripe82X survey to identify 3940 X-ray AGN spanning z=0-2.5, and we measure the rest-frame UVJ colors of each galaxy. We classify AGN as star-forming or quiescent based on their location in a UVJ color diagram. We find that there is not a clear bimodal distribution between AGN in star forming and quiescent galaxies. Furthermore, the most luminous X-ray sources tend to lie in the star forming region, which may indicate a correlation between central engine activity and increased rates of star formation.

6.Properties of the jet in M87 revealed by its helical structure imaged with the VLBA at 8 and 15 GHz

Authors:A. S. Nikonov MPIFR, ASC LPI, Y. Y. Kovalev MPIFR, ASC LPI, MIPT, E. V. Kravchenko MIPT, ASC LPI, I. N. Pashchenko ASC LPI, A. P. Lobanov MPIFR, MIPT

Abstract: We present full-track high-resolution radio observations of the jet of the galaxy M87 at 8 and 15 GHz. These observations were taken over three consecutive days in May 2009 using the Very Long Baseline Array (VLBA), one antenna of the Very Large Array (VLA), and the Effelsberg 100 m telescope. Our produced images have dynamic ranges exceeding 20,000:1 and resolve linear scales down to approximately 100 Schwarzschild radii, revealing a limb-brightened jet and a faint, steep spectrum counter-jet. We performed jet-to-counter-jet analysis, which helped estimate the physical parameters of the flow. The rich internal structure of the jet is dominated by three helical threads, likely produced by the Kelvin-Helmholtz (KH) instability developing in a supersonic flow with a Mach number of approximately 20 and an enthalpy ratio of around 0.3. We produce a CLEAN imaging bias-corrected 8-15GHz spectral index image, which shows spectrum flattening in regions of helical thread intersections. This further supports the KH origin of the observed internal structure of the jet. We detect polarised emission in the jet at distances of approximately 20 milliarcseconds from the core and find Faraday rotation which follows a transverse gradient across the jet. We apply Faraday rotation correction to the polarisation position angle and find that the position angle changes as a function of distance from the jet axis, which suggests the presence of a helical magnetic field.

7.MUSE-ALMA Haloes IX: Morphologies and Stellar Properties of Gas-rich Galaxies

Authors:Arjun Karki, Varsha P. Kulkarni, Simon Weng, Céline Péroux, Ramona Augustin, Matthew Hayes, Mohammadreza Ayromlou, Glenn G. Kacprzak, J. Christopher Howk, Roland Szakacs, Anne Klitsch, Aleksandra Hamanowicz, Alejandra Fresco, Martin A. Zwaan, Andrew D. Biggs, Andrew J. Fox, Susan Kassin, Harald Kuntschner

Abstract: Understanding how galaxies interact with the circumgalactic medium (CGM) requires determining how galaxies morphological and stellar properties correlate with their CGM properties. We report an analysis of 66 well-imaged galaxies detected in HST and VLT MUSE observations and determined to be within $\pm$500 km s$^{-1}$ of the redshifts of strong intervening quasar absorbers at $0.2 \lesssim z \lesssim 1.4$ with H I column densities $N_{\rm H I}$ $>$ $10^{18}$ $\rm cm^{-2}$. We present the geometrical properties (S\'ersic indices, effective radii, axis ratios, and position angles) of these galaxies determined using GALFIT. Using these properties along with star formation rates (SFRs, estimated using the H$\alpha$ or [O II] luminosity) and stellar masses ($M_{*}$ estimated from spectral energy distribution fits), we examine correlations among various stellar and CGM properties. Our main findings are as follows: (1) SFR correlates well with $M_{*}$, and most absorption-selected galaxies are consistent with the star formation main sequence (SFMS) of the global population. (2) More massive absorber counterparts are more centrally concentrated and are larger in size. (3) Galaxy sizes and normalized impact parameters correlate negatively with $N_{\rm H I}$, consistent with higher $N_{\rm H I}$ absorption arising in smaller galaxies, and closer to galaxy centers. (4) Absorption and emission metallicities correlate with $M_{*}$ and sSFR, implying metal-poor absorbers arise in galaxies with low past star formation and faster current gas consumption rates. (5) SFR surface densities of absorption-selected galaxies are higher than predicted by the Kennicutt-Schmidt relation for local galaxies, suggesting a higher star formation efficiency in the absorption-selected galaxies.

1.Dark Matter Halo Spin of the Dwarf Galaxy UGC 5288: Insights from Observations, N-body and Cosmological Simulations

Authors:Sioree Ansar, Sandeep K Kataria, Mousumi Das

Abstract: Dark matter (DM) halo angular momentum is very challenging to determine from observations of galaxies. In this study, we present a new hybrid method of estimating the dimensionless halo angular momentum, halo spin of a gas-rich dwarf barred galaxy UGC5288 using N-Body/SPH simulations. We forward model the galaxy disk properties: stellar and gas mass, surface densities, disk scalelengths, bar length and bar ellipticity from observations. We use the HI rotation curve to constrain the DM halo density profile and further use the bar properties to determine the models that best represent the observed baryonic disk. We compare the halo spin profile from our models to the halo spin profiles of similar mass dwarf galaxy analogues of UGC5288 in the TNG50 simulations. The halo spin profile from our simulated models matches within ballpark values of the median spin profile of UGC5288 analogues in the TNG50 simulations, although there are some uncertainties due to the DM halo evolutionary history.

2.Action-based dynamical models of M31-like galaxies

Authors:Paula Gherghinescu, Payel Das, Robert J. J. Grand, Matthew D. A. Orkney

Abstract: In this work, we present an action-based dynamical equilibrium model to constrain the phase-space distribution of stars in the stellar halo, present-day dark matter distribution, and the total mass distribution in M31-like galaxies. The model comprises a three-component gravitational potential (stellar bulge, stellar disk, and a dark matter halo), and a double-power law distribution function (DF), $f(\mathbf{J})$, which is a function of actions. A Bayesian model-fitting algorithm was implemented that enabled both parameters of the potential and DF to be explored. After testing the model-fitting algorithm on mock data drawn from the model itself, it was applied to a set of three M31-like haloes from the Auriga simulations (Auriga 21, Auriga 23, Auriga 24). Furthermore, we tested the equilibrium assumption and the ability of a double-power law distribution function to represent the stellar halo stars. The model incurs an error in the total enclosed mass of around 10 percent out to 100 kpc, thus justifying the equilibrium assumption. Furthermore, the double-power law DF used proves to be an appropriate description of the investigated M31-like halos. The anisotropy profiles of the halos were also investigated and discussed from a merger history point of view.

3.Searching for new globular clusters in M 31 with Gaia EDR3

Authors:Yilun Wang, Haibo Yuan, Bingqiu Chen, Xinlei Chen, Hao Wu, Zexi Niu, Jifeng Li

Abstract: We found 50 new globular cluster (GC) candidates around M\,31 with Gaia Early Data Release 3 (EDR3), with the help from Pan-STARRS1 DR1 magnitudes and Pan-Andromeda Archaeological Survey (PAndAS) images. Based on the latest Revised Bologna Catalog and \textit{simbad}, we trained 2 Random Forest (RF) classifiers, the first one to distinguish extended sources from point sources and the second one to further select GCs from extended sources. From 1.85 million sources of $16^m{<}g{<}19.5^m$ and within a large area of $\sim$392\,deg$^2$ around M\,31, we selected 20,658 extended sources and 1,934 initial GC candidates. After visual inspection of the PAndAS images to eliminate the contamination of non-cluster sources, particularly galaxies, we finally got 50 candidates. These candidates are divided into 3 types (\textbf{a}, \textbf{b}, \textbf{c}) according to their projected distance $D$ to the center of M\,31 and their probability to be a true GC, $P_{GC}$, which is calculated by our second RF classifier. Among these candidates, 14 are found to be associated (in projection) with the large-scale structures within the halo of M\,31. We also provided several simple parameter criteria for selecting extended sources effectively from the Gaia EDR3, which can reach a completeness of 92.1\% with a contamination fraction lower than 10\%.

4.The first comprehensive Milky Way stellar mock catalogue for the Chinese Space Station Telescope Survey Camera

Authors:Yang Chen, Xiaoting Fu, Chao Liu, Piero Dal Tio, Léo Girardi, Giada Pastorelli, Alessandro Mazzi, Michele Trabucchi, Hao Tian, Dongwei Fan, Paola Marigo, Alessandro Bressan

Abstract: The Chinese Space Station Telescope (CSST) is a cutting-edge two-meter astronomical space telescope currently under construction. Its primary Survey Camera (SC) is designed to conduct large-area imaging sky surveys using a sophisticated seven-band photometric system. The resulting data will provide unprecedented data for studying the structure and stellar populations of the Milky Way. To support the CSST development and scientific projects related to its survey data, we generate the first comprehensive Milky Way stellar mock catalogue for the CSST SC photometric system using the TRILEGAL stellar population synthesis tool. The catalogue includes approximately 12.6 billion stars, covering a wide range of stellar parameters, photometry, astrometry, and kinematics, with magnitude reaching down to $g\,=\,27.5$ mag in the AB magnitude system. The catalogue represents our benchmark understanding of the stellar populations in the Milky Way, enabling a direct comparison with the future CSST survey data. Particularly, it sheds light on faint stars that are hidden from current sky surveys. Our crowding limit analysis based on this catalogue provides compelling evidence for the extension of the CSST Optical Survey (OS) to cover low Galactic latitude regions. The strategic extension of the CSST-OS coverage, combined with this comprehensive mock catalogue, will enable transformative science with the CSST.

5.TEMPLATES: Characterization of a Merger in the Dusty Lensing SPT0418-47 System

Authors:Jared Cathey, Anthony H. Gonzalez, Sidney Lower, Kedar A. Phadke, Justin Spilker, Manuel Aravena, Jack E. Birkin, Simon Birrer, Scott Chapman, Håkon Dahle, Cristopher C. Hayward, Yashar Hezaveh, Ryley Hill, Taylor A. Hutchison, Guillaume Mahler, Daniel P. Marrone, Desika Narayanan, Alexander Navarre, Cassie Reuter, Jane R. Rigby, Keren Sharon, Manuel Solimano, Nikolaus Sulzenauer, Joaquin Vieira, David Vizgan

Abstract: We present JWST and ALMA results for the lensing system SPT0418-47, which includes a strongly-lensed, dusty star-forming galaxy at redshift z=4.225 and an associated multiply-imaged companion. JWST NIRCam and MIRI imaging observations presented in this paper were acquired as part of the Early Release Science program Targeting Extremely Magnified Panchromatic Lensed Arcs and Their Extended Star Formation (TEMPLATES). This data set provides robust, mutiwavelength detection of stellar light in both the main (SPT0418A) and companion (SPT0418B) galaxies, while the ALMA detection of [C II] emission confirms that SPT0418B lies at the same redshift as SPT0418A. From a source plane reconstruction, we infer that the projected physical separation of the two galaxies is $4.42\pm 0.05$ kpc. We derive total magnifications of $\mu=29.5\pm1.2$ and $\mu=4.2\pm 0.9$ for SPT0418A and SPT0418B, respectively. We use both CIGALE and PROSPECTOR to derive stellar masses. The stellar mass ratio of SPT0418A and SPT0418B is approximately 4 to 1 ($4.5\pm 1.0$ for CIGALE and $4.2^{+1.9}_{-1.6}$ for PROSPECTOR). We also see evidence of extended structure associated with SPT0418A in the lensing reconstruction that is suggestive of a tidal feature. Interestingly, the star formation rates and stellar masses of both galaxies are consistent with the main sequence of star-forming galaxies at this epoch, indicating that this ongoing interaction has not noticeably elevated the star formation levels.

1.Is the correlation between the bulge-to-total stellar mass ratio and the number of dwarf galaxies in tension with $Λ$CDM?

Authors:Oliver Müller, Ethan Crosby

Abstract: Previous results suggest that there exists a correlation between the size of the bulge of a galaxy and the number of its dwarf galaxy satellites. This was found to be inconsistent with the standard model of cosmology based on comparisons to semi-analytical dark matter-only simulations, where no such correlation was found. In this work, we extend these studies using the volume-complete ELVES dwarf galaxy catalog, which increases the number of systems compared to previous work by a factor of four. For each giant galaxy we compile the bulge-to-total baryonic mass (B/T) ratio and put it as a function of the number of dwarf galaxies surrounding them within 250 kpc (N$_{250}$). For the 29 galaxy systems in the ELVES catalog, we find a linear relation between B/T and N$_{250}$ which is consistent with previous data. However, for a given stellar mass of the host galaxy this relation is mainly driven by their morphology, where early-type galaxies have a larger B/T ratio and a larger N$_{250}$ than late type galaxies. By investigating spiral galaxies in Illustris-TNG100, we tested whether the inclusion of baryons in the simulations will change the results based on Millennium-II. Contrary to dark matter-only simulations, we do find a correlation between B/T and N$_{250}$, indicating that the standard model of cosmology does predict a correlation. The empirical relation between the number of satellites and the bulge to total stellar mass is therefore not necessarily in tension with $\Lambda$CDM.

2.A candidate of binary black hole system in AGN with broad Balmer emission lines having quite different line widths

Authors:XueGuang Zhang GXU

Abstract: In the manuscript, a candidate of sub-pc binary black hole (BBH) system is reported in SDSS J1257+2023 through different properties of broad Balmer emission lines. After subtractions of host galaxy contributions, Gaussian functions are applied to measure emission lines in SDSS J1257+2023, leading line width (second moment) 760${\rm km/s}$ of broad H$\beta$ to be 0.69 times of line width 1100${\rm km/s}$ of broad H$\alpha$, quite different from normal line width ratio 1.1 of broad H$\beta$ to broad H$\alpha$ in quasars. The quite broader component in broad H$\alpha$ in SDSS J1257+2023 can be confirmed with confidence level higher than $5\sigma$ through F-test technique, through different model functions applied to measure emission lines. The broad Balmer emission lines having different line widths can be naturally explained by a BBH system with different obscurations on central two independent BLRs. Meanwhile, through ZTF light curves and corresponding phase folded light curves well described by sinusoidal function, BBH system expected optical QPOs can be detected with periodicity about 1000days, confirmed with confidence level higher than $3\sigma$ by Generalized Lomb-Scargle periodogram. And through CAR process simulated light curves, confidence level higher than $2\sigma$ can be determined to support the optical QPOs in SDSS J1257+2023 not from intrinsic AGN activities, although the ZTF light curves have short time durations. Moreover, through oversimplified BBH system simulated results, studying different broad Balmer lines as signs of BBH systems in normal quasars with flux ratios around 4 of broad H$\alpha$ to broad H$\beta$ could be done in near future.

3.Laboratory and astronomical discovery of the cyanovinyl radical H2CCCN

Authors:C. Cabezas, J. Tang, M. Agúndez, K. Seiki, Y. Sumiyoshi, Y. Ohshima, B. Tercero, N. Marcelino, R. Fuentetaja, P. de Vicente, Y. Endo, J. Cernicharo

Abstract: We report the first laboratory and interstellar detection of the alpha-cyano vinyl radical (H2CCCN). This species was produced in the laboratory by an electric discharge of a gas mixture of vinyl cyanide, CH2CHCN, and Ne, and its rotational spectrum was characterized using a Balle-Flygare narrowband-type Fourier-transform microwave spectrometer operating in the frequency region of 8-40 GHz. The observed spectrum shows a complex structure due to tunneling splittings between two torsional sublevels of the ground vibronic state, 0+ and 0-, derived from a large-amplitude inversion motion. In addition, the presence of two equivalent hydrogen nuclei makes necessary to discern between ortho- and para-H2CCCN. A least squares analysis reproduces the observed transition frequencies with a standard deviation of ca. 3 kHz. Using the laboratory predictions, this radical is detected in the cold dark cloud TMC-1 using the Yebes 40m telescope and the QUIJOTE line survey. The 404-303 and 505-404 rotational transitions, composed of several hyperfine components, were observed in the 31.0-50.4 GHz range. Adopting a rotational temperature of 6K we derive a column density of (1.4+/-0.2)e11 cm-2 and (1.1+/-0.2)e11 cm-2 for ortho-H2CCCN and para-H2CCCN, respectively. The reactions C + CH3CN, and perhaps also N + CH2CCH, emerge as the most likely routes to H2CCCN in TMC-1.

4.Deciphering the radio-star formation correlation on kpc-scales III. Radio-dim and bright regions in spiral galaxies

Authors:B. Vollmer Universite de Strasbourg, CNRS, Observatoire Astronomique de Strasbourg, France, M. Soida Astronomical Observatory, Jagiellonian University, Krakow, Poland, R. Beck Max-Planck-Institut fuer Radioastronomie, Bonn, Germany, J. D. P. Kenney Yale University Astronomy Department, New Haven, USA

Abstract: The relation between the resolved star formation rate per unit area and the non-thermal radio continuum emission is studied in 21 Virgo cluster galaxies and the two nearby spiral galaxies, NGC6946 and M51. For the interpretation and understanding of our results we used a 3D model where star formation, 2D cosmic ray (CR) propagation, and the physics of synchrotron emission are included. Based on the linear correlation between the star formation rate per unit area and the synchrotron emission and its scatter radio-bright and radio-dim regions can be robustly defined for our sample of spiral galaxies. We identified CR diffusion or streaming as the physical causes of radio-bright regions of unperturbed symmetric spiral galaxies as NGC6946. We identified the probable causes of radio-bright regions in several galaxies as CR transport, via either gravitational tides (M51) or galactic winds (NGC4532) or ram pressure stripping (NGC4330 and NGC4522). Three galaxies are overall radio-dim: NGC4298, NGC4535, and NGC4567. Based on our model of synchrotron-emitting disks we suggest that the overall radio-dim galaxies have a significantly lower magnetic field than expected by equipartition between the magnetic and turbulent energy densities. Radio-bright regions frequently coincide with asymmetric ridges of polarized radio continuum emission, and we found a clear albeit moderate correlation between the polarized radio continuum emission and the radio/SFR ratio. When compression or shear motions of the interstellar medium (ISM) are present in the galactic disk, the radio-bright regions are linked to the commonly observed asymmetric ridges of polarized radio continuum emission and represent a useful tool for the interaction diagnostics. Based on our results, we propose a scenario for the interplay between star formation, CR electrons, and magnetic fields in spiral galaxies.

5.Low-ionization iron-rich Broad Absorption-Line Quasar SDSS J1652+2650: Physical conditions in the ejected gas from excited FeII and metastable HeI

Authors:Balashev S. A., Ledoux C., Noterdaeme P., Boissé P., Krogager J. K., López S., Telikova K. N

Abstract: We present high-resolution VLT/UVES spectroscopy and a detailed analysis of the unique Broad Absorption-Line system towards the quasar SDSS J165252.67+265001.96. This system exhibits low-ionization metal absorption lines from the ground states and excited energy levels of Fe II and Mn II, and the meta-stable 2^3S excited state of He I. The extended kinematics of the absorber encompasses three main clumps with velocity offsets of -5680, -4550, and -1770 km s$^{-1}$ from the quasar emission redshift, $z=0.3509\pm0.0003$, derived from [O II] emission. Each clump shows moderate partial covering of the background continuum source, $C_f \approx [0.53; 0.24; 0.81]$. We discuss the excitation mechanisms at play in the gas, which we use to constrain the distance of the clouds from the Active Galactic Nucleus (AGN) as well as the density, temperature, and typical sizes of the clouds. The number density is found to be $n_{\rm H} \sim 10^4\rm cm^{-3}$ and the temperature $T_e \sim 10^4\rm\,K$, with longitudinal cloudlet sizes of $\gtrsim0.01$ pc. Cloudy photo-ionization modelling of He I$^{*}$, which is also produced at the interface between the neutral and ionized phases, assuming the number densities derived from Fe II, constrains the ionization parameter to be $\log U \sim -3$. This corresponds to distances of a few 100 pc from the AGN. We discuss these results in the more general context of associated absorption-line systems and propose a connection between FeLoBALs and the recently-identified molecular-rich intrinsic absorbers. Studies of significant samples of FeLoBALs, even though rare per se, will soon be possible thanks to large dedicated surveys paired with high-resolution spectroscopic follow-ups.

1.Machine-learning identified molecular fragments responsible for infrared emission features of polycyclic aromatic hydrocarbons

Authors:Zhisen Meng, Yong Zhang, Enwei Liang, Zhao Wang

Abstract: Machine learning feature importance calculations are used to determine the molecular substructures that are responsible for mid and far-infrared (IR) emission features of neutral polycyclic aromatic hydrocarbons (PAHs). Using the extended-connectivity fingerprint as a descriptor of chemical structure, a random forest model is trained on the spectra of 14,124 PAHs to evaluate the importance of 10,632 molecular fragments for each band within the range of 2.761 to 1172.745 microns. The accuracy of the results is confirmed by comparing them with previously studied unidentified infrared emission (UIE) bands. The results are summarized in two tables available as Supplementary Data, which can be used as a reference for assessing possible UIE carriers. We demonstrate that the tables can be used to explore the relation between the PAH structure and the spectra by discussing about the IR features of nitrogen-containing PAHs and super-hydrogenated PAHs.

2.Changing-look Active Galactic Nuclei from the Dark Energy Spectroscopic Instrument. I.Sample from the Early Data

Authors:Wei-Jian Guo, Hu Zou, Victoria Anne Fawcett, Rebecca Canning, Stephanie Juneau, Tamara M. Davis, David M. Alexander, Linhua Jiang, Jessica Nicole Aguilar, Steven Ahlen, David Brooks, Todd Claybaugh, Axel de la Macorra, Peter Doel, Kevin Fanning, Jaime E. Forero-Romero, Satya Gontcho A Gontcho, Klaus Honscheid, Theodore Kisner, Anthony Kremin, Martin Landriau, Aaron Meisner, Ramon Miquel, John Moustakas, Jundan Nie, Zhiwei Pan, Claire Poppett, Francisco Prada, Mehdi Rezaie, Graziano Rossi, Małgorzata Siudek, Eusebio Sanchez, Michael Schubnell, Hee-Jong Seo, Jipeng Sui, Gregory Tarlé, Zhiming Zhou

Abstract: Changing-look Active Galactic Nuclei (CL AGN) can be generally confirmed by the emergence (turn-on) or disappearance (turn-off) of broad emission lines, associated with a transient timescale (about $100\sim5000$ days) that is much shorter than predicted by traditional accretion disk models. We carry out a systematic CL AGN search by cross-matching the spectra coming from the Dark Energy Spectroscopic Instrument and the Sloan Digital Sky Survey. Following previous studies, we identify CL AGN based on $\rm{H}\alpha $, $\rm{H}\beta$, and Mg\,{\sc ii} at $z\leq0.75$ and Mg\,{\sc ii}, C\,{\sc iii}], and C\,{\sc iv} at $z>0.75$. We present 130 CL AGN based on visual inspection and three selection criteria, including 2 $\rm{H}\alpha$, 45 $\rm{H}\beta$, 38 Mg\,{\sc ii}, 61 C\,{\sc iii}], and 10 C\,{\sc iv} CL AGN. Twenty cases show simultaneous appearances/disappearances of two broad emission lines while three AGN exhibit the concurrent appearance of three broad emission lines. We also present 91 CL AGN candidates with significant flux variation of broad emission lines but remaining strong broad components. In the confirmed CL AGN, 42 cases show additional CL candidate features for different lines. In this paper, we find 1) a 95:35 ratio of a turn-on to turn-off CL AGN; 2) the highest redshift CL AGN ($z=3.56$) ever discovered; 3) an upper limit transition timescale ranging from 244 to 5762 days in the rest-frame; 4) the majority of CL AGN follow the bluer-when-brighter trend. Our results greatly increase the current CL census ($30\sim50\%$) and would be conducive to explore the underlying physical mechanism.

3.Dynamics of powerful radio galaxies

Authors:Ross J. Turner, Stanislav S. Shabala

Abstract: Analytical models describing the dynamics of lobed radio sources are essential for interpretation of the tens of millions of radio sources that will be observed by the Square Kilometre Array and pathfinder instruments. We propose that historical models can be grouped into two classes in which the forward expansion of the radio source is driven by either the jet momentum flux or lobe internal pressure. The most recent generation of analytical models combines these limiting cases for a more comprehensive description. We extend the mathematical formalism of historical models to describe source expansion in non-uniform environments, and directly compare different model classes with each other, and with hydrodynamic numerical simulations. We quantify differences in predicted observable characteristics for lobed radio sources due to the different model assumptions for their dynamics. We make our code for the historical models analysed in this review openly available to the community.

4.The nature of compact radio sources: the case of FR0 radio galaxies

Authors:Ranieri D. Baldi INAF-Istituto di Radioastronomia, Bologna, Italy

Abstract: Radio-loud compact radio sources (CRSs) are characterised by morphological compactness of the jet structure centred on the active nucleus of the galaxy. Most of the local elliptical galaxies are found to host a CRS with nuclear luminosities lower than those of typical quasars, $\lesssim$10$^{42}\, {\rm erg\, s}^{-1}$. Recently, low-luminosity CRSs with a LINER-like optical spectrum have been named Fanaroff-Riley (FR) type 0 to highlight their lack of substantially extended radio emission at kpc scales, in contrast with the other Fanaroff-Riley classes, full-fledged FRIs and FRII radio galaxies. FR0s are the most abundant class of radio galaxies in the local Universe, and characterised by a higher core dominance, poorer Mpc-scale environment and smaller (sub-kpc scale, if resolved) jets than FRIs. However, FR0s share similar host and nuclear properties with FRIs. A different accretion-ejection paradigm from that in place in FRIs is invoked to account for the parsec-scale FR0 jets. This review revises the state-of-the-art knowledge about FR0s, their nature, and which open issues the next generation of radio telescopes can solve in this context.

5.Atomic Hydrogen in the Milky Way: A Stepping Stone in the Evolution of Galaxies

Authors:Naomi M. McClure-Griffiths, Snezana Stanimirovic, Daniel R. Rybarczyk

Abstract: Atomic hydrogen (HI) is a critical stepping stone in the gas evolution cycle of the interstellar medium (ISM) of the Milky Way. Hi traces both the cold, premolecular state before star formation and the warm, diffuse ISM before and after star formation. This review describes new, sensitive HI absorption and emission surveys, which, together with high angular and spectral resolution Hi emission data, have revealed the physical properties of HI, its structure, and its association with magnetic fields. We give an overview of the HI phases and discuss how Hi properties depend on the environment and what its structure can tell us about feedback in the ISM. Key findings include the following: - The mass fraction of the cold neutral medium is $\lesssim 40$\% on average, increasing with $A_V$ due to the increase of mean gas density. - The cold disk extends to at least $R\sim 25$ kpc. - Approximately 40% of the HI is warm, with structural characteristics that derive from feedback events. - Cold HI is highly filamentary, whereas warm HI is more smoothly distributed. We summarize future observational and simulation opportunities that can be used to unravel the 3D structure of the atomic ISM and the effects of heating and cooling on HI properties.

6.Revisiting the old end of the Milky Way open cluster age function

Authors:Andrés E. Piatti

Abstract: The age distribution of the open cluster system is a key piece of information to decipher the star formation history of the Milky Way disk. Recently, a remarkable earlier drop of its older end was found, which caught our attention. Precisely, we analyzed in detail the population of open clusters older than 1 Gyr located inside a circle of 2.0 kpc from the Sun contained in the Milky Way Star Cluster catalog, using the Data Release 3.0 of the Gaia survey, and found that it contains a slightly larger old open cluster population with respect to that witnessing the earlier drop age distribution. However, there are still some aspects that deserve further attention in order to undoubtedly handle a statistically complete cluster sample, that allows us to comprehensively know the older end of the open cluster age distribution function. We discuss some reasons that affect such a completeness, among them, the photometric depth of the database employed, the performance of machine learning techniques used to recognize open clusters, the cleaning of cluster color-magnitude diagrams from field star contamination, etc.

7.A New kinematic model of the Galaxy: analysis of the stellar velocity field from \emph{Gaia} Data Release 3

Authors:V. S. Akhmetov, B. Bucciarelli, M. Crosta, M. G. Lattanzi, A. Spagna, P. Re Fiorentin, E. Yu. Bannikova

Abstract: This work presents the results of a kinematic analysis of the Galaxy that uses a new model as applied to the newest available Gaia data. We carry out the Taylor decomposition of the velocity field up to second order for 18 million high luminosity stars (i.e., young OB, giants and subgiants) from the Gaia DR3 data. We determine the components of mean stellar velocities and their first and second partial derivatives (relative to cylindrical coordinates) for more than 28 thousand points in the plane of our Galaxy. We estimate Oort's constants A, B, C, and K and other kinematics parameters and map them as a function of Galactocentric coordinates. The values found confirm the results of our previous works and are in excellent agreement with those obtained by other authors. In addition, the introduction of second order partial derivatives of the stellar velocity field allows us to determine the values of the vertical gradient of the Galaxy azimuthal, radial and vertical velocities. Also, we determine the mean of the Galaxy rotation curve for Galactocentric distances from 4 kpc to 18 kpc by averaging Galactic azimuths in the range -30$^\circ$<$\theta$<+30$^\circ$ about the direction Galactic Centre -- Sun --Galactic anticentre. Maps of the velocity components and of their partial derivatives with respect to coordinates within 10 kpc of the Sun reveal complex substructures, which provide clear evidence of non-axisymmetric features of the Galaxy. Finally, we show evidence of differences in the Northern and Southern hemispheres stellar velocity fields.

8.A giant radio galaxy with three cycles of episodic jet activity from LoTSS DR2

Authors:Kshitij Chavan, Pratik Dabhade, D. J. Saikia

Abstract: The excellent sensitivity and optimum resolution of LoTSS DR2 at 144 MHz has enabled us to discover a giant radio galaxy (J1225+4011) with three distinct episodes of jet activity, making it a member of a class of objects called triple-double radio galaxies (TDRGs). The source extends overall up to 1.35 Mpc in projected size, with the second episode extending to 572 kpc, and the inner episode to 118 kpc. J1225+4011 is only the fourth radio source showing a triple-double radio structure. All four sources have overall sizes greater than 700 kpc, making them giants. We also present the LoTSS 144 MHz map of the TDRG J0929+4146 and report its updated size. Lastly, we have summarised and discussed the radio properties of all TDRGs for the first time to understand their growth and evolution. Our observations suggest that the power of their jets may decrease with time.

9.JADES: deep spectroscopy of a low-mass galaxy at redshift 2.3 quenched by environment

Authors:Lester Sandles, Francesco D'Eugenio, Jakob M. Helton, Roberto Maiolino, Kevin Hainline, William M. Baker, Christina C. Williams, Stacey Alberts, Andrew J. Bunker, Stefano Carniani, Stephane Charlot, Jacopo Chevallard, Mirko Curti, Emma Curtis-Lake, Daniel J. Eisenstein, Zhiyuan Ji, Benjamin D. Johnson, Tobias J. Looser, Tim Rawle, Brant Robertson, Bruno Rodríguez Del Pino, Sandro Tacchella, Hannah Übler, Christopher N. A. Willmer, Chris Willott

Abstract: We report the discovery of a quiescent galaxy at $z=2.34$ with a stellar mass of only $M_\star = 9.5^{+1.8}_{-1.2} \times 10^{8} \mathrm{M}_\odot$, based on deep JWST/NIRSpec spectroscopy. This is the least massive quiescent galaxy found so far at high redshift. We use a Bayesian approach to model the spectrum and photometry, and find the target to have been quiescent for 0.6 Gyr with a mass-weighted average stellar age of 0.8-1.7 Gyr (dominated by systematics). The galaxy displays an inverse colour gradient with radius, consistent with environment-driven quenching. Based on a combination of spectroscopic and robust (medium- and broad-band) photometric redshifts, we identify a galaxy overdensity near the location of the target (5-$\sigma$ above the background level at this redshift). We stress that had we been specifically targetting galaxies within overdensities, the main target would not have been selected on photometry alone; therefore, environment studies based on photometric redshifts are biased against low-mass quiescent galaxies. The overdensity contains three spectroscopically confirmed, massive, old galaxies ($M_\star = 8-17 \times 10^{10} \mathrm{M}_\odot$). The presence of these evolved systems points to accelerated galaxy evolution in overdensities at redshifts z > 2, in agreement with previous works. In projection, our target lies only 35 pkpc away from the most massive galaxy in this overdensity (spectroscopic redshift z = 2.349) which is located close to overdensity's centre. This suggests the low-mass galaxy was quenched by environment, making it possibly the earliest evidence for environment-driven quenching to date.

10.Discovery of the elusive carbonic acid (HOCOOH) in space

Authors:Miguel Sanz-Novo, Víctor M. Rivilla, Izaskun Jiménez-Serra, Jesús Martín-Pintado, Laura Colzi, Shaoshan Zeng, Andrés Megías, Álvaro López-Gallifa, Antonio Martínez-Henares, Sarah Massalkhi, Belén Tercero, Pablo de Vicente, Sergio Martín, David San Andrés, Miguel A. Requena-Torres

Abstract: After a quarter century since the detection of the last interstellar carboxylic acid, acetic acid (CH$_3$COOH), we report the discovery of a new one, the \textit{cis-trans} form of carbonic acid (HOCOOH), toward the Galactic Center molecular cloud G+0.693-0.027. HOCOOH stands as the first interstellar molecule containing three oxygen atoms and also the third carboxylic acid detected so far in the interstellar medium. Albeit the limited available laboratory measurements (up to 65 GHz), we have also identified several pairs of unblended lines directly in the astronomical data (between 75-120 GHz), which allowed us to slightly improve the set of spectroscopic constants. We derive a column density for \textit{cis-trans} HOCOOH of $N$ = (6.4 $\pm$ 0.4) $\times$ 10$^{12}$ cm$^{-2}$, which yields an abundance with respect to molecular H$_2$ of 4.7 $\times$ 10$^{-11}$. Meanwhile, the extremely low dipole moment (about fifteen times lower) of the lower-energy conformer, \textit{cis-cis} HOCOOH, precludes its detection. We obtain an upper limit to its abundance with respect to H$_2$ of $\leq$ 1.2 $\times$10$^{-9}$, which suggests that \textit{cis-cis} HOCOOH might be fairly abundant in interstellar space, although it is nearly undetectable by radio astronomical observations. We derive a \textit{cis-cis}/\textit{cis-trans} ratio $\leq$ 25, consistent with the smaller energy difference between both conformers compared with the relative stability of \textit{trans-} and \textit{cis}-formic acid (HCOOH). Finally, we compare the abundance of these acids in different astronomical environments, further suggesting a relationship between the chemical content found in the interstellar medium and the chemical composition of the minor bodies of the Solar System, which could be inherited during the star formation process.

1.The Rapid ASKAP Continuum Survey III: Spectra and Polarisation In Cutouts of Extragalactic Sources (SPICE-RACS) First Data Release

Authors:Alec J. M. Thomson, David McConnell, Emil Lenc, Timothy J Galvin, Lawrence Rudnick, George Heald, Catherine L. Hale, Stefan W. Duchesne, Craig S. Anderson, Ettore Carretti, Christoph Federrath, B. M. Gaensler, Lisa Harvey-Smith, Marijke Haverkorn, Aidan W. Hotan, Yik Ki Ma, Tara Murphy, N. M. McClure-Griffith, Vanessa A. Moss, Shane P. O'Sullivan, Wasim Raja, Amit Seta, Cameron L. Van Eck, Jennifer L. West, Matthew T. Whiting, Mark H. Wieringa

Abstract: The Australian SKA Pathfinder (ASKAP) radio telescope has carried out a survey of the entire Southern Sky at 887.5MHz. The wide area, high angular resolution, and broad bandwidth provided by the low-band Rapid ASKAP Continuum Survey (RACS-low) allow the production of a next-generation rotation measure (RM) grid across the entire Southern Sky. Here we introduce this project as Spectral and Polarisation in Cutouts of Extragalactic sources from RACS (SPICE-RACS). In our first data release, we image 30 RACS-low fields in Stokes $I$, $Q$, $U$ at 25'' angular resolution, across 744 to 1032MHz with 1MHz spectral resolution. Using a bespoke, highly parallelised, software pipeline we are able to rapidly process wide-area spectro-polarimetric ASKAP observations. Notably, we use 'postage stamp' cutouts to assess the polarisation properties of \ncomponents\ radio components detected in total intensity. We find that our Stokes $Q$ and $U$ images have an rms noise of ~80$\mu$Jy/PSF, and our correction for instrumental polarisation leakage allows us to characterise components with >1% polarisation fraction over most of the field of view. We produce a broadband polarised radio component catalogue that contains \nrms\ RM measurements over an area of ~1300deg^2 with an average error in RM of 1.6+1.1-1.0rad/m^2, and an average linear polarisation fraction 3.4+3.0-1.6%. We determine this subset of components using the conditions that the polarised signal-to-noise ratio is $>8$, the polarisation fraction is above our estimated polarised leakage, and the Stokes $I$ spectrum has a reliable model. Our catalogue provides an areal density of $4\pm2$ RMs/deg^2; an increase of $\sim4$ times over the previous state-of-the-art (Taylor et al. 2009). Meaning that, having used just 3% of the RACS-low sky area, we have produced the 3rd largest RM catalogue to date. This catalogue has broad applications for studying...

2.The torsion of stellar streams and the overall shape of galactic gravity's source

Authors:Adriana Bariego-Quintana, Felipe J. Llanes-Estrada

Abstract: Flat rotation curves v(r) are naturally explained by elongated (prolate) Dark Matter (DM) distributions, and we have provided competitive fits to the SPARC database. To further probe the geometry of the halo one needs out-of-plane observables. Stellar streams, poetically analogous to airplane contrails, but caused by tidal dispersion of massive substructures such as satellite dwarf galaxies, would lie on a plane should the DM-halo gravitational field be spherically symmetric. We aim at establishing stellar stream torsion, a local observable that measures the deviation from planarity in differential curve geometry. We perform small-scale simulations of tidally distorted star clusters to check that indeed a central force center produces negligible torsion. Turning to observational data, we identify among the known streams those that are at largest distance from the galactic center and likely not affected by the Magellanic clouds, as most promising for the study, and by means of polynomial fits we extract their differential torsion. We find that the torsion of the few known streams that should be sensitive to most of the Milky Way's DM Halo is much larger than expected for a central spherical bulb alone. This is consistent with non-sphericity of the halo. Future studies of stellar stream torsion with larger samples and further out of the galactic plane should be able to extract the ellipticity of the halo to see whether it is just a slight distortion of a spherical shape or rather ressembles a more elongated cigar.

3.The dual nature of the tidal tails of NGC 5904 (M5)

Authors:Andrés E. Piatti

Abstract: The tangential velocity dispersion of stars belonging to the Milky Way globular cluster's tidal tails has recently been found from N-body simulations to be a parameter that distinguishes between cored and cuspy profiles of low-mass dwarf galaxy dark matter subhaloes where that globular cluster formed, and the in-situ formation scenario. In this context, we discovered that M5's tidal tails are composed by stars at two different metallicity regimes ([Fe/H] ~ -1.4 dex and -2.0 dex). The more metal-rich tidal tail stars are of the same metal content than M5's members and have a tangential velocity dispersion that coincides with the predicted value for a cuspy formation scenario (subhalo mass $\sim$ 10$^9$ M$_{\odot}$). The more metal-poor stars, that are found along the entire M5 tidal tails and have similar distributions to their more metal-rich counterparts in the M5 colour-magnitude diagram and orbit trajectory, have a tangential velocity dispersion that refers to a cored subhalo (mass $\sim$ 10$^9$ M$_{\odot}$) or an in-situ formation scenario. In order to reconcile the dual distribution of M5 tidal tail stars, in kinematics and chemistry, we propose that M5 collided with another more metal-poor and less massive globular cluster anytime before or after it was accreted into the Milky Way.

4.The environments of hyper-compact H II regions. I. G345.0061+01.794 B

Authors:Toktarkhan Komesh, Guido Garay, Aruzhan Omar, Robert Estalella, Zhandos Assembay, Dalei Li, Andrés Guzmán, Jarken Esimbek, Jiasheng Huang, Yuxin He, Nazgul Alimgazinova, Meiramgul Kyzgarina, Nurman Zhumabay, Arailym Manapbayeva

Abstract: We report high angular resolution observations, made with the Atacama Large Millimeter Array in band 6, of high excitation molecular lines of CH3CN and SO2 and of the H29a radio recombination line towards the G345.0061+01.794 B HC H II region, in order to investigate the physical and kinematical characteristics of its surroundings. Emission was detected in all observed components of the J=14-13 rotational ladder of CH3CN and in the 30(4,26)-30(3,27) and 32(4,28)-32(3,29) lines of SO2. The peak of the velocity integrated molecular emission is located \sim0.4" northwest of the peak of the continuum emission. The first-order moment images and channel maps show a velocity gradient, of 1.1 km s-1 arcsec-1, across the source, and a distinctive spot of blueshifted emission towards the peak of the zero-order moment. We derived that the rotational temperature decreases from 230 Kelvin at the peak position to 137 Kelvin at its edge, indicating that our molecular observations are probing a hot molecular core that is internally excited. The emission in the H29a line arises from a region of 0.65" in size, whose peak is coincident with that of the dust continuum, has a center velocity of -18.1pm0.9 km s-1 and a width (FWHM) of 33.7pm2.3 km s-1. We modeled the kinematical characteristics of "central blue spot" feature as due to infalling motions, deriving a central mass of 126.0pm8.7M_sun. Our observations indicate that this HC H II region is surrounded by a compact structure of hot molecular gas, which is rotating and infalling toward a central mass, that is most likely confining the ionized region.

1.Investigating 16 Open Clusters in the Kepler/K2-Gaia DR3 field. I. Membership, Binary, and Rotation

Authors:Liu Long, Shanlao Bi, Jinhua Zhang, Xianfei Zhang, Liyun Zhang, Zhishuai Ge, Tanda Li, Xunzhou Chen, Yaguang Li, Lifei Ye, TianCheng Sun, Jianzhao Zhou

Abstract: Using data from the Gaia Data Release 3 (Gaia DR3) and Kepler/K2, we present a catalog of 16 open clusters with ages ranging from 4 to 4000 Myr, which provides detailed information on membership, binary systems, and rotation. We assess the memberships in 5D phase space, and estimate the basic parameters of each cluster. Among the 20,160 members, there are 4,381 stars identified as binary candidates and 49 stars as blue straggler stars. The fraction of binaries vary in each cluster, and the range between 9% to 44%. We obtain the rotation periods of 5,467 members, of which 4,304 are determined in this work. To establish a benchmark for the rotation-age-color relation, we construct color-period diagrams. We find that the rotational features of binaries are similar to that of single stars, while features for binaries are more scattered in the rotation period. Moreover, the morphology of the color-period relationship is already established for Upper Scorpius at the age of 19 Myr, and some stars of varying spectral types (i.e. FG-, K-, and M-type) show different spin-down rates after the age of ~110 Myr. By incorporating the effects of stalled spin-down into our analysis, we develop an empirical rotation-age-color relation, which is valid with ages between 700 - 4000 Myr and colors corresponding to a range of 0.5 < (G_BP-G_RP)0 < 2.5 mag.

2.Interstellar Conditions Deduced from Interstellar Neutral Helium Observed by IBEX and Global Heliosphere Modeling

Authors:P. Swaczyna, M. Bzowski, J. Heerikhuisen, M. A. Kubiak, F. Rahmanifard, E. J. Zirnstein, S. A. Fuselier, A. Galli, D. J. McComas, E. Möbius, N. A. Schwadron

Abstract: In situ observations of interstellar neutral (ISN) helium atoms by the IBEX-Lo instrument onboard the Interstellar Boundary Explorer (IBEX) mission are used to determine the velocity and temperature of the pristine very local interstellar medium (VLISM). Most ISN helium atoms penetrating the heliosphere, known as the primary population, originate in the pristine VLISM. As the primary atoms travel through the outer heliosheath, they charge exchange with He$^+$ ions in slowed and compressed plasma creating the secondary population. With more than 2.4 million ISN helium atoms sampled by IBEX during ISN seasons 2009-2020, we compare the observations with predictions of a parametrized model of ISN helium transport in the heliosphere. We account for the filtration of ISN helium atoms at the heliospheric boundaries by charge exchange and elastic collisions. We examine the sensitivity of the ISN helium fluxes to the interstellar conditions described by the pristine VLISM velocity, temperature, magnetic field, and composition. We show that comprehensive modeling of the filtration processes is critical for interpreting ISN helium observations, as the change in the derived VLISM conditions exceeds the statistical uncertainties when accounting for these effects. The pristine VLISM parameters found by this analysis are the flow speed (26.6 km s$^{-1}$), inflow direction in ecliptic coordinates (255.7$^\circ$, 5.04$^\circ$), temperature (7350 K), and B-V plane inclination to the ecliptic plane (53.7$^\circ$). The derived pristine VLISM He$^+$ density is $9.7\times10^3$ cm$^{-3}$. Additionally, we show a strong correlation between the interstellar plasma density and magnetic field strength deduced from these observations.

3.Zwicky Transient Facility and Globular Clusters: the gr-Band Period-Luminosity Relations for Mira Variables at Maximum Light and Their Applications to Local Galaxies

Authors:Chow-Choong Ngeow, Jia-Yu Ou, Anupam Bhardwaj, Josiah Purdum, Ben Rusholme, Avery Wold

Abstract: Based on 14 Miras located in 7 globular clusters, we derived the first gr-band period-luminosity (PL) at maximum light for the large-amplitude Mira variables using the multi-year light-curve data collected from the Zwicky Transient Facility (ZTF). Since Miras are red variables, we applied a color-term correction to subsets of ZTF light curves, and found that such corrections do not have a large impact on period determinations. We applied our derived PL relations to the known extragalactic Miras in five local galaxies (Sextans, Leo I, Leo II, NGC6822 and IC1613), and determined their Mira-based distances. We demonstrated that our PL relations can be applied to short-period (<300 days) Miras, including those in the two most distant galaxies (NGC6822 and IC1613) in our sample even when only a portion of the light-curves around maximum light have detections. We have also shown that the long-period extragalactic Miras do not follow the PL relations extrapolated to longer periods. Hence, our derived PL relations are only applicable to the short-period Miras, which will be discovered in abundance in local galaxies within the era of Vera C. Rubin Observatory's Legacy Survey of Space and Time.

1.Infrared Spectroscopy of Nearby Radio Active Early-Type Galaxies -- II: Spectral Atlas

Authors:Mark Durré, Jeremy Mould, Michael Brown, Tristan Reynolds

Abstract: We present a near infrared spectroscopic atlas of nearby, bright early-type galaxies with radio emission, containing 163 galaxies observed by the Palomar 200" TripleSpec instrument, measuring the emission line fluxes for H, He, [Fe II] and H$_2$ and determined the nuclear excitation mechanisms. By stacking spectra, we deduced the H$_2$ excitation temperature ($1957\pm182$ K) and dominant excitation mechanism (thermal and shock heating combined) from the $\textit{K}$-band emission line sequence. Stacking also produces an "average" spectrum of absorption features and spectral indices from the literature; the CO12 absorption line index vs. $\textit{J-K}$ colour shows a trend of stronger nuclear activity producing a weaker CO12 index and a redder (flatter) continuum. The correlations between the radio and the emission-line luminosities finds a trend with radio power; however, the large scatter in the upper limits shows that the two are not directly coupled and the duty cycles of SF and AGN activity are not synchronised.

2.Discovery of spectacular quasar-driven superbubbles in red quasars

Authors:Lu Shen, Guilin Liu, Zhicheng He, Nadia L. Zakamska, Eilat Glikman, Jenny E. Greene, Weida Hu, Guobin Mou, Dominika Wylezalek, David S. N. Rupke

Abstract: Quasar-driven outflows on galactic scales are a routinely invoked ingredient for galaxy formation models. We report the discovery of ionized gas nebulae as traced by [O III] $\lambda$5007 AA emission surrounding three luminous red quasars at $z \sim 0.4$ from Gemini Integral Field Unit (IFU) observations. All these nebulae feature unprecedented pairs of "superbubbles" extending $\sim$20 kpc in diameter, and the line-of-sight velocity difference between the red- and blue-shifted bubbles reaches up to $\sim$1200 km s$^{-1}$. Their spectacular dual-bubble morphology (in analogy to the Galactic "Fermi bubbles") and their kinematics provide unambiguous evidence for galaxy-wide quasar-driven outflows, in parallel with the quasi-spherical outflows similar in size from luminous Type-1 and -2 quasars at concordant redshift. These bubble pairs manifest themselves as a signpost of the short-lived superbubble ``break-out'' phase, when the quasar wind drives the bubbles to escape the confinement from the dense environment and plunge into the galactic halo with a high-velocity expansion.

3.Bending instabilities of m=1 mode in disc galaxies: interplay between dark matter halo and vertical pressure

Authors:Sagar S. Goyary, Kanak Saha, H. Shanjit Singh, Suchira Sarkar

Abstract: A self-gravitating, differentially rotating galactic disc under vertical hydrostatic equilibrium is supported by the vertical pressure gradient force against the gravitational collapse. Such discs are known to support various bending modes e.g., warps, corrugation, or scalloping (typically, higher order bending modes) of which m=1 bending modes (warps) are the most prevalent ones in galactic discs. Here, we present a detailed theoretical analysis of the bending instability in realistic models of disc galaxies in which an exponential stellar disc is under vertical equilibrium and residing in a cold rigid dark matter halo. A quadratic eigenvalue equation describing the bending modes is formulated and solved for the complete eigen spectrum for a set of model disc galaxies by varying their physical properties such as disc scale-height, and dark matter halo mass. It is shown that the vertical pressure gradient force can excite unstable bending modes in such a disc as well as large scale discrete modes. Further, it is shown that the unstable eigen-modes in a thinner disc grow faster than those in a thicker disc. The bending instabilities are found to be suppressed in discs dominated by massive dark matter halo. We estimate the growth timescales and corresponding wavelength of the m=1 unstable bending modes in Milky Way like galaxies and discuss its implication.

4.Star formation efficiency and AGN feedback in narrow-line Seyfert 1 galaxies with fast X-ray nuclear winds

Authors:Quentin Salomé, Yair Krongold, Anna Lia Longinotti, Manuela Bischetti, Santiago García-Burillo, Olga Vega, Miguel Sánchez-Portal, Chiara Feruglio, María Jesús Jiménez-Donaire, Maria Vittoria Zanchettin

Abstract: We present the first systematic study of the molecular gas and star formation efficiency in a sample of ten narrow-line Seyfert 1 galaxies selected to have X-ray Ultra Fast Outflows and, therefore, to potentially show AGN feedback effects. CO observations were obtained with the IRAM 30m telescope in six galaxies and from the literature for four galaxies. We derived the stellar mass, star formation rate, AGN and FIR dust luminosities by fitting the multi-band spectral energy distributions with the CIGALE code. Most of the galaxies in our sample lie above the main sequence (MS) and the molecular depletion time is one to two orders of magnitude shorter than the one typically measured in local star-forming galaxies. Moreover, we found a promising correlation between the star formation efficiency and the Eddington ratio, as well as a tentative correlation with the AGN luminosity. The role played by the AGN activity in the regulation of star formation within the host galaxies of our sample remains uncertain (little or no effect? positive feedback?). Nevertheless, we can conclude that quenching by the AGN activity is minor and that star formation will likely stop in a short time due to gas exhaustion by the current starburst episode.

5.Towards an automatic approach to modelling the circumgalactic medium: new tools for mock making and fitting of metal profiles in large surveys

Authors:Alessia Longobardi, Matteo Fossati, Michele Fumagalli, Bhaskar Agarwal, Emma Lofthouse, Marta Galbiati, Rajeshwari Dutta, Trystyn A. M. Berg, Louise A. Welsh

Abstract: We present two new tools for studying and modelling metal absorption lines in the circumgalactic medium. The first tool, dubbed ``NMF Profile Maker'' (NMF$-$PM), uses a non-negative matrix factorization (NMF) method and provides a robust means to generate large libraries of realistic metal absorption profiles. The method is trained and tested on 650 unsaturated metal absorbers in the redshift interval $z=0.9-4.2$ with column densities between $11.2 \le \log{(\mathrm{N/cm^{-2}})} \le 16.3$, obtained from high-resolution ($R> 4000$) and high signal-to-noise ratio ($S/N \ge 10$) quasar spectroscopy. To avoid spurious features, we train on infinite $S/N$ Voigt models of the observed line profiles derived using the code ``Monte-Carlo Absorption Line Fitter'' (MC$-$ALF), a novel automatic Bayesian fitting code that is the second tool we present in this work. MC$-$ALF is a Monte Carlo code based on nested sampling that, without the need for any prior guess or human intervention, can decompose metal lines into individual Voigt components. Both MC$-$ALF and NMF$-$PM are made publicly available to allow the community to produce large libraries of synthetic metal profiles and to reconstruct Voigt models of absorption lines in an automatic fashion. Both tools contribute to the scientific effort of simulating and analysing metal absorbers in very large spectroscopic surveys of quasars like the ongoing Dark Energy Spectroscopic Instrument (DESI), the 4-meter Multi-Object Spectroscopic Telescope (4MOST), and the WHT Enhanced Area Velocity Explorer (WEAVE) surveys.

6.Disk and Envelope Streamers of the GGD27-MM1 Massive Protostar

Authors:M. Fernández-López Instituto Argentino de Radioastronomía, Argentina, J. M. Girart Institut de Ciències de l'Espai, Catalunya Institut d'Estudis Espacials de Catalunya, Catalunya, J. A. López-Vázquez Academia Sinica Institute of Astronomy and Astrophysics, Taiwan, R. Estalella Departament de Física Quàntica i Astrofísica, Barcelona, Spain, G. Busquet Departament de Física Quàntica i Astrofísica, Barcelona, Spain Institut de Ciències del Cosmos, Barcelona, Spain Institut d'Estudis Espacials de Catalunya, Catalunya, S. Curiel Instituto de Astronomía, México, N. Añez-López Université Paris-Saclay, France

Abstract: We present new Atacama Large (sub)Millimeter Array 0.98 mm observations of the continuum emission and several molecular lines toward the high-mass protostellar system GGD27-MM1, driving the HH 80-81 radio-jet. The detailed analysis of the continuum and the CH$_3$CN molecular emission allows us to separate the contributions from the dust content of the disk (extending up to 190 au), the molecular content of the disk (extending from 140 to 360 au), and the content of the envelope, revealing the presence of several possible accretion streamers (also seen in other molecular tracers, such as CH$_3$OH). We analyze the physical properties of the system, producing temperature and column density maps, and radial profiles for the disk and the envelope. We qualitatively reproduce the trajectories and line-of-sight velocities of the possible streamers using a theoretical model approach. An ad-hoc model of a flared disk comprising a hot dust disk embedded in cold gas fits the H$_2$S emission, which revealed the molecular disk as crescent-shape with a prominent central absorption. Another fit to the central absorption spectrum suggests that the absorption is probably caused by different external cold layers from the envelope or the accretion streamers. Finally, the analysis of the rotation pattern of the different molecular transitions in the molecular disk, suggests that there is an inner zone devoid of molecular content.

7.The physical and chemical structure of Sagittarius B2 VIIIa. Dust and ionized gas contributions to the full molecular line survey of 47 hot cores

Authors:T. Möller I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937 Köln, Germany, P. Schilke I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937 Köln, Germany, Á. Sánchez-Monge I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937 Köln, Germany Institut de Ciències de l'Espai Institut d'Estudis Espacials de Catalunya, A. Schmiedeke I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937 Köln, Germany Green Bank Observatory, 155 Observatory Rd, Green Bank, WV 24944, F. Meng I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937 Köln, Germany University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China

Abstract: Sagittarius B2 (Sgr B2) is a giant molecular cloud complex in the central molecular zone of our Galaxy hosting several sites of high-mass star formation. The two main centers of activity are Sgr B2(M) and Sgr B2(N), which contain 27 and 20 continuum sources, respectively. Our analysis aims to be a comprehensive modeling of each core spectrum, where we take the complex interaction between molecular lines, dust attenuation, and free-free emission arising from HII regions into account. In this work, we determine the dust and, if HII regions are contained, the parameters of the free-free thermal emission of the ionized gas for each core, and derive a self-consistent description of the continuum levels of each core. Using the high sensitivity of ALMA, we characterize the physical and chemical structure of these continuum sources and gain better insight into the star formation process within the cores. We used ALMA to perform an unbiased spectral line survey of all 47 sources in ALMA band 6 with a frequency coverage from 211 GHz to 275 GHz. In order to model the free-free continuum contribution of a specific core, we fit the contained recombination lines (RRLs) to obtain the electron temperatures and the emission measures, where we use an extended XCLASS program to describe RRLs and free-free continuum simultaneously. In contrast to previous analyses, we derived the corresponding parameters here not only for each core, but also for their local surrounding envelope, and determined their physical properties. The distribution of RRLs we found in the core spectra closely fits the distribution of HII regions described in previous analyses. For the cores we determine average dust temperatures of around 236 K (Sgr B2(M)) and 225 K (Sgr B2(N)), while the electronic temperatures are located in a range between 3800 K and 23800 K.

8.Submillimeter Observations of Magnetic Fields in Massive Star-forming Region W75N

Authors:Lingzhen Zeng, Qizhou Zhang, Felipe O. Alves, Tao-Chung Ching, Josep M. Girart, Junhao Liu

Abstract: This paper presents the results of full polarization observations of the massive star-forming region W75N, conducted with 3 arcsec spatial resolutions at 345 GHz using the Submillimeter Array (SMA). The magnetic field structures in the dense cores of the region are derived using the linearly polarized continuum emission. The overall magnetic field strength and orientation are found to agree with those from the previous observations. The plane-of-sky (POS) component of the magnetic field in the region was calculated to be 0.8 \pm 0.1 mG using the angular dispersion function (ADF) method. Further analyses involving the polarization-intensity gradient-local gravity method and H13CO+ (4-3) line data indicated that the cloud is undergoing global gravitational collapse and the magnetic field is shaped by gravity and outflows in the dense core regions.

9.Physical parameters of stellar population in star formation regions of galaxies

Authors:A. S. Gusev, F. Sakhibov, O. V. Egorov, V. S. Kostiuk, E. V. Shimanovskaya

Abstract: We present the results of a study of young unresolved stellar groupings (clusters, OB associations, and their complexes) associated with HII regions, based on the coupling of spectroscopic, photometric and H{\alpha} spectrophotometric observations of star formation regions. Along with our own observations, we use a part of the spectroscopic and H{\alpha} data from the literature and open databases. The study is based on the catalogue of 1510 star formation regions with ages ~10-20 Myr in 19 spiral galaxies, compiled by us earlier. We study the morphology of stellar groupings and their relation with the associated H{\alpha} emission region. Extinctions, gas chemical abundances, and sizes of star formation regions are measured. Using numerical SSP models computed for metallicities fixed from observations to intrinsic colours of the studied star formation regions, we estimated ages and masses of stellar population of 400 young stellar groupings. Different relations between observational and physical parameters of the young stellar population in star formation regions are discussed.

10.The Spatial and Emission Properties of the Large [O III] Emission Nebula Near M31

Authors:Robert A. Fesen, Stefan Kimeswenger, J. Michael Shull, Marcel Drechsler, Xavier Strottner, Yann Sainty, Bray Falls, Christophe Vergnes, Nicolas Martino, Sean Walker, Justin Rupert

Abstract: Drechsler et al. (2023) reported the unexpected discovery of a 1.5 degree long [O III] emission nebula 1.2 degrees southeast of the M31 nucleus. Here we present additional images of this large emission structure, called SDSO, along with radial velocity and flux measurements from low-dispersion spectra. Independent sets of [O III] images show SDSO to be composed of broad streaks of diffuse emission aligned NE-SW. Deep H$\alpha$ images reveal no strong coincident emission suggesting a high [O III]/H$\alpha$ ratio. We also find no other [O III] emission nebulosity as bright as SDSO within several degrees of M31 and no filamentary H$\alpha$ emission connected to SDSO. Optical spectra taken along the arc's northern limb reveal [O III] $\lambda\lambda$4959,5007 emissions matching the location and extent seen in our [O III] images. The heliocentric velocity of this [O III] nebulosity is $-9.8 \pm 6.8$ km s$^{-1}$ with a peak surface brightness of $(4\pm2) \times 10^{-18}$ erg s$^{-1}$ cm$^{-2}$ arcsec$^{-2}$ ($\sim$0.55 Rayleigh). We discuss SDSO as a possible unrecognized supernova remnant, a large and unusually nearby planetary nebula, a stellar bow shock nebula, or an interaction of M31's outer halo gas with high-velocity circumgalactic gas. We conclude that galactic origins for SDSO are unlikely and favor instead an extragalactic M31 halo--circumgalactic cloud interaction scenario, despite the nebula's low radial velocity. We then describe new observations that may help resolve the true nature and origin of this large nebulosity so close to M31 in the sky.

11.Ultraviolet Compactness of High-Redshift Galaxies as a Tracer of Early-Stage Gas Infall, Stochastic Star Formation, and Offset from the Fundamental Metallicity Relation

Authors:Danial Langeroodi, Jens Hjorth

Abstract: Recent compilations of NIRSpec emission line galaxies have shown a mild redshift evolution of the FMR at $z > 4$, indicating that the FMR alone is not fully capable of capturing the redshift evolution of the mass-metallicity relation: $z > 4$ galaxies appear more metal-poor than the FMR predictions. There is evidence that the most metal-deficient high-redshift galaxies are also the most compact. In this work, we further investigate this anti-correlation by leveraging the wealth of data gathered through the first cycle of JWST. We compile a sample of 427 $z > 3$ galaxies covered by both the NIRSpec prism and NIRCam short-wavelength photometry, consisting of 334 galaxies from the publicly available programs and 93 galaxies from the first data release of the JADES program. We use this sample to infer the redshift evolution of the FMR from $z = 3$ to $z \sim 10$, further confirming the previously reported mild redshift evolution. We measure the rest-ultraviolet (UV) sizes of $z > 4$ galaxies, inferring the mass-size relation at $z = 4-10$ with a power-law slope of $0.21 \pm 0.04$. We investigate the redshift evolution of the mass-size relation, finding that at a fixed stellar mass, higher redshift galaxies appear more compact. The degree of this redshift evolution depends on the stellar mass, with the lowest mass galaxies showing the strongest redshift evolution and the most massive galaxies ($\log(M_{\star}/M_{\odot}) > 9$) showing no redshift evolution. We investigate the anti-correlation between the compactness of galaxies and their gas-phase metallicities, finding that the more compact galaxies appear more metal-deficient and therefore more offset from the local calibration of the FMR. (abridged)

1.EDGE: The direct link between mass growth history and the extended stellar haloes of the faintest dwarf galaxies

Authors:Alex Goater, Justin I. Read, Noelia E. D. Noël, Matthew D. A. Orkney, Stacy Y. Kim, Martin P. Rey, Eric P. Andersson, Oscar Agertz, Andrew Pontzen, Roberta Vieliute, Dhairya Kataria, Kiah Jeneway

Abstract: Ultra-faint dwarf galaxies (UFDs) are commonly found in close proximity to the Milky Way and other massive spiral galaxies. As such, their projected stellar ellipticity and extended light distributions are often thought to owe to tidal forces. In this paper, we study the projected stellar ellipticities and faint stellar outskirts of tidally isolated ultra-faints drawn from the 'Engineering Dwarfs at Galaxy Formation's Edge' (EDGE) cosmological simulation suite. Despite their tidal isolation, our simulated dwarfs exhibit a wide range of projected ellipticities ($0.03 < \varepsilon < 0.85$), with many possessing anisotropic extended stellar haloes that mimic tidal tails, but owe instead to late-time accretion of lower mass companions. Furthermore, we find a strong causal relationship between ellipticity and formation time of an UFD, which is robust to a wide variation in the feedback model. We show that the distribution of projected ellipticities in our suite of simulated EDGE dwarfs matches well with that of 21 Local Group dwarf galaxies. Given the ellipticity in EDGE arises from an ex-situ accretion origin, the agreement in shape indicates the ellipticities of some observed dwarfs may also originate from a similar non-tidal scenario. The orbital parameters of these observed dwarfs further support that they are not currently tidally disrupting. If the baryonic content in these galaxies is still tidally intact, then the same may be true for their dark matter content, making these galaxies in our Local Group pristine laboratories for testing dark matter and galaxy formation models.

2.Accelerated structural evolution of galaxies in a starbursting cluster at z=2.51

Authors:Can Xu, Tao Wang, Qiusheng Gu, Anita Zanella, Ke Xu, Hanwen Sun, Veronica Strazzullo, Francesco Valentino, Raphael Gobat, Emanuele Daddi, David Elbaz, Mengyuan Xiao, Shiying Lu, Luwenjia Zhou

Abstract: Structural properties of cluster galaxies during their peak formation epoch, $z \sim 2-4$ provide key information on whether and how environment affects galaxy formation and evolution. Based on deep HST/WFC3 imaging towards the z=2.51 cluster, J1001, we explore environmental effects on the structure, color gradients, and stellar populations of a statistical sample of cluster SFGs. We find that the cluster SFGs are on average smaller than their field counterparts. This difference is most pronounced at the high-mass end ($M_{\star} > 10^{10.5} M_{\odot}$) with nearly all of them lying below the mass-size relation of field galaxies. The high-mass cluster SFGs are also generally old with a steep negative color gradient, indicating an early formation time likely associated with strong dissipative collapse. For low-mass cluster SFGs, we unveil a population of compact galaxies with steep positive color gradients that are not seen in the field. This suggests that the low-mass compact cluster SFGs may have already experienced strong environmental effects, e.g., tidal/ram pressure stripping, in this young cluster. These results provide evidence on the environmental effects at work in the earliest formed clusters with different roles in the formation of low and high-mass galaxies.

3.The filament determination depends on the tracer: comparing filaments based on dark matter particles and galaxies in the GAEA semi-analytic model

Authors:Daria Zakharova, Benedetta Vulcani, Gabriella De Lucia, Lizhi Xie, Michaela Hirschmann, Fabio Fontanot

Abstract: Filaments are elongated structures that connect groups and clusters of galaxies and are visually the striking feature in cosmological maps. In the literature, typically filaments are defined only using galaxies, assuming that these are good tracers of the dark matter distribution, despite the fact that galaxies are a biased indicator. Here we apply the topological filament extractor DisPerSE to the predictions of the semi-analytic code GAEA to investigate the correspondence between the properties of $z=0$ filaments extracted using the distribution of dark matter and the distribution of model galaxies evolving within the same large-scale structure. We focus on filaments around massive clusters with a mass comparable to Virgo and Coma, with the intent of investigating the influence of massive systems and their feeding filamentary structure on the physical properties of galaxies. We apply different methods to compare the properties of filaments based on the different tracers and study how the sample selection impacts the extraction. Overall, filaments extracted using different tracers agree, although they never coincide totally. We also find that the number of filaments ending up in the massive clusters identified using galaxies distribution is typically underestimated with respect to the corresponding dark matter filament extraction.

4.Variability, flaring and coherence -- the complementarity of the maser and superradiance regimes

Authors:Martin Houde, Fereshteh Rajabi, Gordon C. MacLeod, Sharmila Goedhart, Yoshihiro Tanabe, Stefanus P. van den Heever, Christopher M. Wyenberg, Yoshinori Yonekura

Abstract: We discuss the role that coherence phenomena can have on the intensity variability of spectral lines associated with maser radiation. We do so by introducing the fundamental cooperative radiation phenomenon of (Dicke's) superradiance and discuss its complementary nature to the maser action, as well as its role in the flaring behaviour of some maser sources. We will consider examples of observational diagnostics that can help discriminate between the two, and identify superradiance as the source of the latter. More precisely, we show how superradiance readily accounts for the different time-scales observed in the multi-wavelength monitoring of the periodic flaring in G9.62+0.20E.

5.A reproduction of the Milky Way's Faraday rotation measure map in galaxy simulations from global to local scales

Authors:Stefan Reissl, Ralf S. Klessen, Eric W. Pellegrini, Daniel Rahner, Rüdiger Pakmor, Robert Grand, Facundo Gomez, Federico Marinacci, Volker Springel

Abstract: Magnetic fields are of critical importance for our understanding of the origin and long-term evolution of the Milky Way. This is due to their decisive role in the dynamical evolution of the interstellar medium (ISM) and their influence on the star-formation process. Faraday rotation measures (RM) along many different sightlines across the Galaxy are a primary means to infer the magnetic field topology and strength from observations. However, the interpretation of the data has been hampered by the failure of previous attempts to explain the observations in theoretical models and to synthesize a realistic multi-scale all-sky RM map. We here utilize a cosmological magnetohydrodynamic (MHD) simulation of the formation of the Milky Way, augment it with a novel star cluster population synthesis model for a more realistic structure of the local interstellar medium, and perform detailed polarized radiative transfer calculations on the resulting model. This yields a faithful first principles prediction of the Faraday sky as observed on Earth. The results reproduce the observations of the Galaxy not only on global scales, but also on local scales of individual star-forming clouds. They also imply that the Local Bubble containing our Sun dominates the RM signal over large regions of the sky. Modern cosmological MHD simulations of the Milky Way's formation, combined with a simple and plausible model for the fraction of free electrons in the ISM, explain the RM observations remarkably well, thus indicating the emergence of a firm theoretical understanding of the genesis of magnetic fields in our Universe across cosmic time.

6.Chemistry of multiple stellar populations in the mono-metallic, in situ, bulge globular cluster NGC 6388

Authors:Eugenio Carretta INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Angela Bragaglia INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna

Abstract: We present the homogeneous abundance analysis for a combined sample of 185 giants in the bulge globular cluster (GC) NGC 6388. Our results are used to describe the multiple stellar populations and differences or analogies with bulge field stars. Proton-capture elements indicate that a single class of first-generation polluters is sufficient to reproduce both the extreme and intermediate parts of the anti-correlations among light elements O, Na, Mg, and Al, which is at odds with our previous results based on a much smaller sample. The abundance pattern of other species in NGC 6388 closely tracks the trends observed in bulge field stars. In particular, the alpha-elements, including Si, rule out an accreted origin for NGC 6388, confirming our previous results based on iron-peak elements, chemo-dynamical analysis, and the age-metallicity relation. The neutron-capture elements are generally uniform, although the [Zr/Fe] ratio shows an intrinsic scatter, correlated to Na and Al abundances. Instead, we do not find enhancement in neutron-capture elements for stars whose photometric properties would classify NGC 6388 as a type II GC. Together with the homogeneity in [Fe/H] we found in a previous paper, this indicates we need to better understand the criteria to separate classes of GCs, coupling photometry, and spectroscopy. These results are based on abundances of 22 species (O, Na, Mg, Al, Si, Ca, Ti, Sc, V, Cr, Mn, Fe, Co, Ni, Zn, Y, Zr, Ba, La, Ce, Nd, and Eu) from UVES spectra sampling proton-, alpha-, neutron-capture elements, and Fe-peak elements. For 12 species, we also obtain abundances in a large number of giants (up to 150) from GIRAFFE spectra.

1.Beyond spectroscopy. II. Stellar parameters for over twenty million stars in the northern sky from SAGES DR1 and Gaia DR3

Authors:Yang Huang, Timothy C. Beers, Hai-Bo Yuan, Ke-Feng Tan, Wei Wang, Jie Zheng, Chun Li, Young Sun Lee, Hai-Ning Li, Jing-Kun Zhao, Xiang-Xiang Xue, Yu-Juan Liu, Hua-Wei Zhang, Xue-Ang Sun, Ji Li, Hong-Rui Gu, Christian Wolf, Christopher A. Onken, Ji-Feng Liu, Zhou Fan, Gang Zhao

Abstract: We present precise photometric estimates of stellar parameters, including effective temperature, metallicity, luminosity classification, distance, and stellar age, for nearly 26 million stars using the methodology developed in the first paper of this series, based on the stellar colors from the Stellar Abundances and Galactic Evolution Survey (SAGES) DR1 and Gaia EDR3. The optimal design of stellar-parameter sensitive $uv$ filters by SAGES has enabled us to determine photometric-metallicity estimates down to $-3.5$, similar to our previous results with the SkyMapper Southern Survey (SMSS), yielding a large sample of over five million metal-poor (MP; [Fe/H]$\le -1.0$) stars and nearly one million very metal-poor (VMP; [Fe/H]$\le -2.0$) stars. The typical precision is around $0.1$ dex for both dwarf and giant stars with [Fe/H]$>-1.0$, and 0.15-0.25/0.3-0.4 dex for dwarf/giant stars with [Fe/H]$<-1.0$. Using the precise parallax measurements and stellar colors from Gaia, effective temperature, luminosity classification, distance and stellar age are further derived for our sample stars. This huge data set in the Northern sky from SAGES, together with similar data in the Southern sky from SMSS, will greatly advance our understanding of the Milky Way, in particular its formation and evolution.

2.The abundance and excitation of molecular anions in interstellar clouds

Authors:M. Agundez, N. Marcelino, B. Tercero, I. Jimenez-Serra, J. Cernicharo

Abstract: We report new observations of molecular anions with the Yebes 40m and IRAM 30m telescopes toward the cold dense clouds TMC-1 CP, Lupus-1A, L1527, L483, L1495B, and L1544. We detected for the first time C3N- and C5N- in Lupus-1A and C4H- and C6H- in L483. In addition, we report new lines of C6H- toward the six targeted sources, of C4H- toward TMC-1 CP, Lupus-1A, and L1527, and of C8H- and C3N- in TMC-1 CP. Excitation calculations indicate that the lines of anions accessible to radiotelescopes run from subthermally excited to thermalized as the size of the anion increases, with the degree of departure from thermalization depending on the H2 volume density and the line frequency. We noticed that the collision rate coefficients available for the radical C6H cannot explain various observational facts, which advises for a revisitation of the collision data for this species. The observations presented here, together with observational data from the literature, are used to model the excitation of interstellar anions and to constrain their abundances. In general, the anion-to-neutral ratios derived here agree within 50 % (a factor of two at most) with literature values, when available, except for the C4H-/C4H ratio, which shows higher differences due to a revision of the dipole moment of C4H. From the set of anion-to-neutral abundance ratios derived two conclusions can be drawn. First, the C6H-/C6H ratio shows a tentative trend in which it increases with increasing H2 density, as expected from theoretical grounds. And second, it is incontestable that the higher the molecular size the higher the anion-to-neutral ratio, which supports a formation mechanism based on radiative electron attachment. Nonetheless, calculated rate coefficients for electron attachment to the medium size species C4H and C3N are probably too high and too low, respectively, by more than one order of magnitude.

3.Physical properties of circumnuclear ionising clusters. I. NGC 7742

Authors:S. Zamora, A. I. Díaz

Abstract: This work aims to derive the physical properties of the CNSFRs in the ring of the face-on spiral NGC 7742 using IFS observations. We have selected 88 individual ionising clusters that power HII regions populating the ring of the galaxy that may have originated in a minor merger event. For the HII regions the rate of Lyman continuum photon emission is between 0.025 and 1.5 10$^{51}$ which points to these regions being ionised by star clusters. Their electron density, ionisation parameter, filling factor and ionised hydrogen mass show values consistent with those found in other studies of similar regions and their metal abundances as traced by sulphur have been found to be between 0.25 and 2.4 times solar, with most regions showing values slightly below solar. The equivalent temperature of the ionising clusters is relatively low, below 40000 K which is consistent with the high elemental abundances derived. The young stellar population of the clusters has contributions of ionising and non-ionising populations with ages around 5 Ma and 300 Ma respectively. The masses of ionising clusters once corrected for the contribution of underlying non-ionising populations were found to have a mean value of 3.5 $\times$ 10$^4$ M$_{\odot}$, comparable to the mass of ionised gas and about 20 \% of the corrected photometric mass.

4.Self-consistent Combined HST, K-band, and Spitzer Photometric Catalogs of the BUFFALO Survey Fields

Authors:Amanda Pagul, F. Javier Sánchez, Iary Davidzon, Anton M. Koekemoer, Hakim Atek, Renyue Cen, Lukas J. Furtak, Mathilde Jauzac, Guillaume Mahler, Bahram Mobasher, Mireia Montes, Mario Nonino, Keren Sharon, Charles L. Steinhardt, John R. Weaver

Abstract: This manuscript presents new astronomical source catalogs using data from the BUFFALO Survey. These catalogs contain detailed information for over 100,000 astronomical sources in the 6 BUFFALO clusters: Abell 370, Abell 2744, Abell S1063, MACS 0416, MACS 0717, and MACS 1149 spanning a total 240 arcmin^2. The catalogs include positions and forced photometry measurements of these objects in the F275W, F336W, F435W, F606W, F814W, F105W, F125W, F140W, and F160W HST -bands, Keck-NIRC2/VLT-HAWKI Ks band, and IRAC Channel 1 and 2 bands. Additionally, we include photometry measurements in the F475W, F625W, and F110W bands for Abell 370. This catalog also includes photometric redshift estimates computed via template fitting using LePhare. When comparing to spectroscopic reference, we obtain an outlier fraction of 9.2% and scatter, normalized median absolute deviation (NMAD), of 0.062. The catalogs are publicly available for their use by the community.

5.The individual abundance distributions of disc stars across birth radii in GALAH

Authors:Kaile Wang, Andreia Carrillo, Melissa K. Ness, Tobias Buck

Abstract: Individual abundances in the Milky Way disc record stellar birth properties (e.g. age, birth radius ($R_{\rm birth}$)) and capture the diversity of the star-forming environments over time. Assuming an analytical relationship between ([Fe/H], [$\alpha$/Fe]) and $R_{\rm birth}$, we examine the distributions of individual abundances [X/Fe] of elements C, O, Mg, Si, Ca ($\alpha$), Al (odd-z), Mn (iron-peak), Y, and Ba (neutron-capture) for stars in the Milky Way. We want to understand how these elements might differentiate environments across the disc. We assign tracks of $R_{\rm birth}$ in the [$\alpha$/Fe] vs. [Fe/H] plane as informed by expectations from simulations for $\sim 59,000$ GALAH stars in the solar neighborhood ($R\sim7-9$ kpc) which also have inferred ages. Our formalism for $R_{\rm birth}$ shows that older stars ($\sim$10 Gyrs) have a $R_{\rm birth}$ distribution with smaller mean values (i.e., $\bar{R}_{\mbox{birth}}$$\sim5\pm0.8$ kpc) compared to younger stars ($\sim6$ Gyrs; $\bar{R}_{\mbox{birth}}$$\sim10\pm1.5$ kpc), for a given [Fe/H], consistent with inside-out growth. The $\alpha$-, odd-z, and iron-peak element abundances decrease as a function of $R_{\rm birth}$, whereas the neutron-capture abundances increase. The $R_{\rm birth}$-[Fe/H] gradient we measure is steeper compared to the present-day gradient (-0.067 dex/kpc vs -0.058 dex/kpc), which we also find true for $R_{\rm birth}$-[X/Fe] gradients. These results (i) showcase the feasibility of relating the birth radius of stars to their element abundances, (ii) the abundance gradients across $R_{\rm birth}$ are steeper than those over current radius, and (iii) offer an observational comparison to expectations on element abundance distributions from hydrodynamical simulations.

6.Redshifting galaxies from DESI to JWST CEERS: Correction of biases and uncertainties in quantifying morphology

Authors:Si-Yue Yu, Cheng Cheng, Yue Pan, Fengwu Sun, Yang A. Li

Abstract: Observations of high-redshift galaxies with unprecedented detail have now been rendered possible with JWST. However, accurately quantifying their morphology remains uncertain due to potential biases and uncertainties. To address this issue, we used a sample of 1816 nearby DESI galaxies, with a mass range of $10^{9.75-11.25}M_{\odot}$, to compute artificial images of galaxies of the same mass located at $0.75\leq z\leq 3$ and observed at rest-frame optical wavelength in CEERS. We analyzed the effects of cosmological redshift on the measurements of Petrosian radius ($R_p$), half-light radius ($R_{50}$), asymmetry ($A$), concentration ($C$), axis ratio ($q$), and S\'ersic index ($n$). Our results show that $R_p$ and $R_{50}$, calculated using non-parametric methods, are slightly overestimated due to PSF smoothing, while $R_{50}$, $q$, and $n$ obtained through model fitting does not exhibit significant biases. We improve the computation of $A$ by incorporating a more accurate noise effect removal procedure. Due to PSF asymmetry, there is a minor overestimation of $A$ for intrinsically symmetric galaxies. However, for intrinsically asymmetric galaxies, PSF smoothing dominates and results in an underestimation of $A$, an effect that becomes more significant with higher intrinsic $A$ or at lower resolutions. Moreover, PSF smoothing also leads to an underestimation of $C$, which is notably more pronounced in galaxies with higher intrinsic $C$ or at lower resolutions. We developed functions based on resolution level, defined as $R_p/$FWHM, for correcting these biases and the associated statistical uncertainties. Applying these corrections, we measured the bias-corrected morphology for the simulated CEERS images and we find that the derived quantities are in good agreement with their intrinsic values -- except for $A$, which is robust only for angularly large galaxies where $R_p/{\rm FWHM}\geq 5$.

1.A model for molecular hydrogen-dependent star formation in simulations of galaxy evolution

Authors:Ezequiel Lozano, Cecilia Scannapieco, Sebastian E. Nuza

Abstract: Star formation, together with the associated chemical and energy feedback, is one of the most important processes in galaxy evolution. The star formation activity in galaxies defines and affects many of their fundamental properties, such as stellar mass, morphology and chemical enrichment levels. Simple models for star formation in cosmological hydrodynamical simulations have shown to be successful in reproducing the star formation rate (SFR) levels and shapes of different types of galaxies. However, with the advent of high-resolution simulations and more detailed observations, more sophisticated star formation models are needed; in particular, to better understand the relation between star formation and the amount of gas in the atomic and molecular phases. In this work, we apply a novel star formation model, recently developed to work in the context of hydrodynamical simulations, to the study of the SFR in Milky Way-mass galaxies. The new implementation describes the formation of molecular hydrogen from atomic material, considering also possible dependencies with the chemical abundance of the gas. This allows to implement various star formation models, where the SFR of a gas cloud is determined by the atomic and/or molecular gas phases, and to compare their predictions to recent observational results.

1.Exploring the Angular Momentum - Atomic Gas Content Connection with EAGLE and IllustrisTNG

Authors:Jennifer A. Hardwick, Luca Cortese, Danail Obreschkow, Claudia Lagos, Adam R. H. Stevens, Barbara Catinella, Lilian Garrett-Smithson

Abstract: We use the EAGLE (Evolution and Assembly of GaLaxies and their Environments) and IllustrisTNG (The Next Generation) cosmological simulations to investigate the properties of the baryonic specific angular momentum (j), baryonic mass (M) and atomic gas fraction ($f_{\rm{atm}}$) plane for nearby galaxies. We find an excellent agreement between EAGLE and TNG, with both also matching quite well the results obtained with xGASS (eXtended GALEX Arecibo SDSS Survey) for gas fractions greater than 0.01. This implies that the disagreements previously identified between xGASS and predictions from simple analytical disc stability arguments also holds true for EAGLE and TNG. For lower gas fraction (the regime currently unconstrained by observations), both simulations deviate from the plane but still maintain good agreement with each other. Despite the challenges posed by resolution limits at low gas fractions, our findings suggest a potential disconnect between angular momentum and gas fraction in the gas-poor regime, implying that not all gas-poor galaxies have low specific angular momentum.

1.Ageing and Quenching through the ageing diagram II: physical characterization of galaxies

Authors:Pablo Corcho-Caballero, Yago Ascasibar, Luca Cortese, Sebastián F. Sánchez, Ángel López-Sánchez, Amelia Fraser-McKelvie, Tayyaba Zafar

Abstract: The connection between quenching mechanisms, which rapidly turn star-forming systems into quiescent, and the properties of the galaxy population remains difficult to discern. In this work we investigate the physical properties of MaNGA and SAMI galaxies at different stages of their star formation history. Specifically, we compare galaxies with signatures of recent quenching (Quenched) -- $\rm H(\alpha)$ in absorption and low $D_n(4000)$ -- with the rest of the low star-forming and active population (Retired and Ageing, respectively). The analysis is performed in terms of characteristics such as the total stellar mass, half-light radius, velocity-to-dispersion ratio, metallicity, and environment. We find that the Ageing population comprises a heterogeneous mixture of galaxies, preferentially late-type systems, with diverse physical properties. Retired galaxies, formerly Ageing or Quenched systems, are dominated by early-type high-mass galaxies found both at low and dense environments. Most importantly, we find that recently quenched galaxies are consistent with a population of compact low-mass satellite systems, with higher metallicities than their Ageing analogues. We argue that this is compatible with being quenched after undergoing a star-burst phase induced by environmental processes (e.g. ram pressure). However, we also detect a non-negligible fraction of field central galaxies likely quenched by internal processes. This study highlights that, in order to constrain the mechanisms driving galaxy evolution, it is crucial to distinguish between old (Retired) and recently quenched galaxies, thus requiring at least two estimates of the specific star formation rate over different timescales.

2.ACA CO($J=2-1$) Mapping of the Nearest Spiral Galaxy M33. I. Initial Results and Identification of Molecular Clouds

Authors:Kazuyuki Muraoka, Ayu Konishi, Kazuki Tokuda, Hiroshi Kondo, Rie E. Miura, Tomoka Tosaki, Sachiko Onodera, Nario Kuno, Masato I. N. Kobayashi, Kisetsu Tsuge, Hidetoshi Sano, Naoya Kitano, Shinji Fujita, Atsushi Nishimura, Toshikazu Onishi, Kazuya Saigo, Rin I. Yamada, Fumika Demachi, Kengo Tachihara, Yasuo Fukui, Akiko Kawamura

Abstract: We present the results of ALMA-ACA 7 m-array observations in $^{12}$CO($J=2-1$), $^{13}$CO($J=2-1$), and C$^{18}$O($J=2-1$) line emission toward the molecular-gas disk in the Local Group spiral galaxy M33 at an angular resolution of 7".31 $\times$ 6".50 (30 pc $\times$ 26 pc). We combined the ACA 7 m-array $^{12}$CO($J=2-1$) data with the IRAM 30 m data to compensate for emission from diffuse molecular-gas components. The ACA+IRAM combined $^{12}$CO($J=2-1$) map clearly depicts the cloud-scale molecular-gas structure over the M33 disk. Based on the ACA+IRAM $^{12}$CO($J=2-1$) cube data, we cataloged 848 molecular clouds with a mass range from $10^3$ $M_{\odot}$ to $10^6$ $M_{\odot}$. We found that high-mass clouds ($\geq 10^5 M_{\odot}$) tend to associate with the $8 \mu$m-bright sources in the spiral arm region, while low-mass clouds ($< 10^5 M_{\odot}$) tend to be apart from such $8 \mu$m-bright sources and to exist in the inter-arm region. We compared the cataloged clouds with GMCs observed by the IRAM 30 m telescope at 49 pc resolution (IRAM GMC: Corbelli et al. 2017), and found that a small IRAM GMC is likely to be identified as a single molecular cloud even in ACA+IRAM CO data, while a large IRAM GMC can be resolved into multiple ACA+IRAM clouds. The velocity dispersion of a large IRAM GMC is mainly dominated by the line-of-sight velocity difference between small clouds inside the GMC rather than the internal cloud velocity broadening.

3.Molecular outflow in the reionization-epoch quasar J2054-0005 revealed by OH 119 $μ$m observations

Authors:Dragan Salak, Takuya Hashimoto, Akio K. Inoue, Tom J. L. C. Bakx, Darko Donevski, Yuma Sugahara, Yoichi Tamura, Nario Kuno, Yusuke Miyamoto, Seiji Fujimoto, Suphakorn Suphapolthaworn

Abstract: Molecular outflows are expected to play a key role in galaxy evolution at high redshift. To study the impact of outflows on star formation at the epoch of reionization, we performed sensitive ALMA observations of OH 119 $\mu$m toward J2054-0005, a luminous quasar at $z=6.04$. The OH line is detected and exhibits a P-Cygni profile that can be fitted with a broad blue-shifted absorption component, providing unambiguous evidence of an outflow, and an emission component at near-systemic velocity. The mean and terminal outflow velocities are estimated to be $v_\mathrm{out}\approx670~\mathrm{km~s}^{-1}$ and $1500~\mathrm{km~s}^{-1}$, respectively, making the molecular outflow in this quasar one of the fastest at the epoch of reionization. The OH line is marginally resolved for the first time in a quasar at $z>6$, revealing that the outflow extends over the central 2 kpc region. The mass outflow rate is comparable to the star formation rate ($\dot{M}_\mathrm{out}/\mathrm{SFR}\sim1$), indicating rapid ($\sim10^7~\mathrm{yr}$) quenching of star formation. The mass outflow rate in a sample star-forming galaxies and quasars at $4<z<6.4$ exhibits a near-linear correlation with the total infrared luminosity, although the scatter is large. Owing to the high outflow velocity, a large fraction (up to $\sim50\%$) of the outflowing molecular gas may be able to escape from the host galaxy into the intergalactic medium.

4.VINTERGATAN-GM: How do mergers affect the satellite populations of MW-like galaxies?

Authors:Gandhali D. Joshi, Andrew Pontzen, Oscar Agertz, Martin P. Rey, Justin Read, Florent Renaud

Abstract: We investigate the impact of a galaxy's merger history on its system of satellites using the new \textsc{vintergatan-gm} suite of zoom-in hydrodynamical simulations of Milky Way-mass systems. The suite simulates five realizations of the same halo with targeted `genetic modifications' (GMs) of a $z \approx 2$ merger, but resulting in the same halo mass at $z=0$. We find that differences in the satellite stellar mass functions last for 2.25-4.25 Gyr after the $z \approx 2$ merger; specifically, the haloes that have undergone smaller mergers host up to 60% more satellites than those of the larger merger scenarios. However, by $z=0$ these differences in the satellite stellar mass functions have been erased. The differences in satellite numbers seen soon after the mergers are driven by several factors, including the timings of major mergers, the masses and satellite populations of the central and merging systems, and the subsequent extended history of minor mergers. The results persist when measured at fixed central stellar mass rather than fixed time, implying that a host's recent merger history can be a significant source of scatter when reconstructing its dynamical properties from its satellite population.

5.Molecular Abundance of the Circumnuclear Region Surrounding an Active Galactic Nucleus in NGC 1068 based on Imaging Line Survey in the 3-mm Band with ALMA

Authors:Taku Nakajima, Shuro Takano, Tomoka Tosaki, Akio Taniguchi, Nanase Harada, Toshiki Saito, Masatoshi Imanishi, Yuri Nishimura, Takuma Izumi, Yoichi Tamura, Kotaro Kohno, Eric Herbst

Abstract: We present an imaging molecular line survey in the 3-mm band (85-114 GHz) focused on one of the nearest galaxies with an active galactic nucleus (AGN), NGC 1068, based on observations taken with the Atacama Large Millimeter/submillimeter Array (ALMA). Distributions of 23 molecular transitions are obtained in the central ~3 kpc region, including both the circumnuclear disk (CND) and starburst ring (SBR) with 60 and 350 pc resolution. The column densities and relative abundances of all the detected molecules are estimated under the assumption of local thermodynamic equilibrium in the CND and SBR. Then, we discuss the physical and chemical effects of the AGN on molecular abundance corresponding to the observation scale. We found that H13CN, SiO, HCN, and H13CO+ are abundant in the CND relative to the SBR. In contrast, 13CO is more abundant in the SBR. Based on the calculated column density ratios of N(HCN)/N(HCO+), N(HCN)/N(CN), and other molecular distributions, we conclude that the enhancement of HCN in the CND may be due to high-temperature environments resulting from strong shocks, which are traced by the SiO emission. Moreover, the abundance of CN in the CND is significantly lower than the expected value of the model calculations in the region affected by strong radiation. The expected strong X-ray irradiation from the AGN has a relatively lower impact on the molecular abundance in the CND than mechanical feedback.

6.The Classification of Galaxy Morphology in H-band of COSMOS-DASH Field: a combination-based machine learning clustering model

Authors:Yao Dai, Jun Xu, Jie Song, Guanwen Fang, Chichun Zhou, Shuo Ba, Yizhou Gu, Zesen Lin, Xu Kong

Abstract: By applying our previously developed two-step scheme for galaxy morphology classification, we present a catalog of galaxy morphology for H-band selected massive galaxies in the COSMOS-DASH field, which includes 17292 galaxies with stellar mass $M_{\star}>10^{10}~M_{\odot}$ at $0.5<z<2.5$. The classification scheme is designed to provide a complete morphology classification for galaxies via a combination of two machine-learning steps. We first use an unsupervised machine learning method (i.e., bagging-based multi-clustering) to cluster galaxies into five categories: spherical (SPH), early-type disk (ETD), late-type disk (LTD), irregular (IRR), and unclassified (UNC). About 48\% of galaxies (8258/17292) are successfully clustered during this step. For the remaining sample, we adopt a supervised machine learning method (i.e., GoogLeNet) to classify them, during which galaxies that are well-classified in the previous step are taken as our training set. Consequently, we obtain a morphology classification result for the full sample. The t-SNE test shows that galaxies in our sample can be well aggregated. We also measure the parametric and nonparametric morphologies of these galaxies. We find that the S\'{e}rsic index increases from IRR to SPH and the effective radius decreases from IRR to SPH, consistent with the corresponding definitions. Galaxies from different categories are separately distributed in the $G$--$M_{20}$ space. Such consistencies with other characteristic descriptions of galaxy morphology demonstrate the reliability of our classification result, ensuring that it can be used as a basic catalog for further galaxy studies.

7.The AMIGA sample of isolated galaxies. XIV. Disc breaks and interactions through ultra-deep optical imaging

Authors:P. M. Sánchez-Alarcón, J. Román, J. H. Knapen, L. Verdes-Montenegro, S. Comerón, R. M. Rich, J. E. Beckman, M. Argudo-Fernández, P. Ramírez-Moreta, J. Blasco, E. Unda-Sanzana, J. Garrido, S. Sánchez-Exposito

Abstract: In the standard cosmological model of galaxy evolution, mergers and interactions play a fundamental role in shaping galaxies. Galaxies that are currently isolated are thus interesting, allowing us to distinguish between internal and external processes affecting the galactic structure. However, current observational limits may obscure crucial information in the low-mass or low-brightness regime. We use optical imaging of a subsample of the AMIGA catalogue of isolated galaxies to explore the impact of different factors on the structure of these galaxies. We study the type of disc break as a function of the degree of isolation and the presence of interaction indicators like tidal streams or plumes only detectable in the low surface brightness regime. We present deep optical imaging of a sample of 25 isolated galaxies. Through careful data processing and analysis techniques, the surface brightness limits achieved are comparable to those to be obtained on the 10-year LSST coadds. The extreme depth of our imaging allows us to study the interaction signatures of 20 galaxies, given that the presence of Galactic cirrus is a strong limiting factor in the characterisation of interactions for the remaining 5 of them. We detect previously unreported interaction features in 8 (40%) galaxies in our sample. We identify 9 galaxies (36%) showing an exponential disc (Type I), 14 galaxies (56%) with down-bending (Type II) profile and only 2 galaxies (8%) with up-bending (Type III) profiles. Isolated galaxies have considerably more purely exponential discs and fewer up-bending surface brightness profiles than field or cluster galaxies. We suggest that major mergers produce up-bending profiles while a threshold in star formation probably forms down-bending profiles. Unperturbed galaxies, evolving slowly with a low star formation rate could cause the high rate of Type I discs in isolated galaxies observed.

8.On the origin of globular clusters in a hierarchical Universe

Authors:Gabriella De Lucia, J. M. Diederik Kruijssen, Sebastian Trujillo-Gomez, Michaela Hirschmann, Lizhi Xie

Abstract: We present an end-to-end description of the formation process of globular clusters (GCs) which combines a treatment for their formation and dynamical evolution within galaxy haloes with a state-of-the-art semi-analytic simulation of galaxy formation. Our approach allows us to obtain exquisite statistics to study the effect of the environment and assembly history of galaxies, while still allowing a very efficient exploration of the parameter space of star cluster physics. Our reference model, including both efficient cluster disruption during galaxy mergers and a model for the dynamical friction of GCs within the galactic potential, accurately reproduces the observed correlation between the total mass in GCs and the parent halo mass. A deviation from linearity is predicted at low halo masses, which is driven by a strong dependence on morphological type: bulge-dominated galaxies tend to host larger masses of GCs than their later-type counterparts of similar stellar mass. While the significance of the difference might be affected by resolution at the lowest halo masses considered, this is a robust prediction of our model and represents a natural consequence of the assumption that cluster migration from the disk to the halo is triggered by galaxy mergers. Our model requires an environmental dependence of GC radii to reproduce the observed mass distribution of GCs in our Galaxy at the low-mass end. At GC masses $>10^6\,{\rm M}_\odot$, our model predicts fewer GCs than observed due to an overly aggressive treatment of dynamical friction. The metallicity distribution measured for Galactic GCs is well reproduced by our model, even though it predicts systematically younger GCs than observed. We argue that this adds further evidence for an anomalously early formation of the stars in our Galaxy.

9.Subaru High-$z$ Exploration of Low-Luminosity Quasars (SHELLQs). XVIII. The Dark Matter Halo Mass of Quasars at $z\sim6$

Authors:Junya Arita, Nobunari Kashikawa, Yoshiki Matsuoka, Wanqiu He, Kei Ito, Yongming Liang, Rikako Ishimoto, Takehiro Yoshioka, Yoshihiro Takeda, Kazushi Iwasawa, Masafusa Onoue, Yoshiki Toba, Masatoshi Imanishi

Abstract: We present, for the first time, dark matter halo (DMH) mass measurement of quasars at $z\sim6$ based on a clustering analysis of 107 quasars. Spectroscopically identified quasars are homogeneously extracted from the HSC-SSP wide layer over $891\,\mathrm{deg^2}$. We evaluate the clustering strength by three different auto-correlation functions: projected correlation function, angular correlation function, and redshift-space correlation function. The DMH mass of quasars at $z\sim6$ is evaluated as $5.0_{-4.0}^{+7.4}\times10^{12}\,h^{-1}M_\odot$ with the bias parameter $b=20.8\pm8.7$ by the projected correlation function. The other two estimators agree with these values, though each uncertainty is large. The DMH mass of quasars is found to be nearly constant $\sim10^{12.5}\,h^{-1}M_\odot$ throughout cosmic time, suggesting that there is a characteristic DMH mass where quasars are always activated. As a result, quasars appear in the most massive halos at $z \sim 6$, but in less extreme halos thereafter. The DMH mass does not appear to exceed the upper limit of $10^{13}\,h^{-1}M_\odot$, which suggests that most quasars reside in DMHs with $M_\mathrm{halo}<10^{13}\,h^{-1}M_\odot$ across most of the cosmic time. Our results supporting a significant increasing bias with redshift are consistent with the bias evolution model with inefficient AGN feedback at $z\sim6$. The duty cycle ($f_\mathrm{duty}$) is estimated as $0.019\pm0.008$ by assuming that DMHs in some mass interval can host a quasar. The average stellar mass is evaluated from stellar-to-halo mass ratio as $M_*=6.5_{-5.2}^{+9.6}\times10^{10}\,h^{-1}M_\odot$, which is found to be consistent with [C II] observational results.

10.Do old globular clusters in low mass galaxies disprove modified gravity?

Authors:Michal Bílek, Hongsheng Zhao, Benoit Famaey, Srikanth T. Nagesh, Françoise Combes, Oliver Müller, Michael Hilker, Pavel Kroupa, Rodrigo Ibata

Abstract: The controversy "dark matter vs. modified gravity" constitutes a major topic of discussion. It was proposed that dynamical friction could be used to discriminate between the two alternatives. Analytic calculations indicate that, with modified gravity, globular clusters (GCs) of low-mass galaxies experience much stronger dynamical friction than in the equivalent system with Newtonian gravity and dark matter. As a result, in modified gravity the old GCs of low mass galaxies should have already settled in the centers of the galaxies. This is not observed. Here we report on our efforts to verify the analytic results by self-consistent simulations with the MOND-type (modified Newtonian dynamics) gravity. The core stalling mechanism, that was not considered in the analytic calculations, prevents GCs to settle in centers of ultra-diffuse galaxies. For isolated dwarf galaxies, which are gas-rich objects, supernova explosions prevent the GCs from settling.

11.Dust attenuation, dust content and geometry of star-forming galaxies

Authors:Junkai Zhang, Stijn Wuyts, Sam E. Cutler, Lamiya A. Mowla, Gabriel B. Brammer, Ivelina G. Momcheva, Katherine E. Whitaker, Pieter van Dokkum, Natascha M. Förster Schreiber, Erica J. Nelson, Patricia Schady, Carolin Villforth, David Wake, Arjen van der Wel

Abstract: We analyse the joint distribution of dust attenuation and projected axis ratios, together with galaxy size and surface brightness profile information, to infer lessons on the dust content and star/dust geometry within star-forming galaxies at 0 < z <2.5. To do so, we make use of large observational datasets from KiDS+VIKING+HSC-SSP and extend the analysis out to redshift z = 2.5 using the HST surveys CANDELS and 3D-DASH. We construct suites of SKIRT radiative transfer models for idealized galaxies observed under random viewing angles with the aim of reproducing the aforementioned distributions, including the level and inclination dependence of dust attenuation. We find that attenuation-based dust mass estimates are at odds with constraints from far-infrared observations, especially at higher redshifts, when assuming smooth star and dust geometries of equal extent. We demonstrate that UV-to-near-IR and far-infrared constraints can be reconciled by invoking clumpier dust geometries for galaxies at higher redshifts and/or very compact dust cores. We discuss implications for the significant wavelength- and redshift-dependent differences between half-light and half-mass radii that result from spatially varying dust columns within -- especially massive -- star-forming galaxies.

12.Abundance Analysis of Stars at Large Radius in the Sextans Dwarf Spheroidal Galaxy

Authors:Ian U. Roederer, Andrew B. Pace, Vinicius M. Placco, Nelson Caldwell, Sergey E. Koposov, Mario Mateo, Edward W. Olszewski, Matthew G. Walker

Abstract: We present stellar parameters and chemical abundances of 30 elements for five stars located at large radii (3.5-10.7 times the half-light radius) in the Sextans dwarf spheroidal galaxy. We selected these stars using proper motions, radial velocities, and metallicities, and we confirm them as metal-poor members of Sextans with -3.34 <= [Fe/H] <= -2.64 using high-resolution optical spectra collected with the Magellan Inamori Kyocera Echelle spectrograph. Four of the five stars exhibit normal abundances of C (-0.34 <= [C/Fe] <= +0.36), mild enhancement of the alpha elements Mg, Si, Ca, and Ti ([alpha/Fe] = +0.12 +/- 0.03), and unremarkable abundances of Na, Al, K, Sc, V, Cr, Mn, Co, Ni, and Zn. We identify three chemical signatures previously unknown among stars in Sextans. One star exhibits large overabundances ([X/Fe] > +1.2) of C, N, O, Na, Mg, Si, and K, and large deficiencies of heavy elements ([Sr/Fe] = -2.37 +/- 0.25, [Ba/Fe] = -1.45 +/- 0.20, [Eu/Fe] < +0.05), establishing it as a member of the class of carbon-enhanced metal-poor stars with no enhancement of neutron-capture elements. Three stars exhibit moderate enhancements of Eu (+0.17 <= [Eu/Fe] <= +0.70), and the abundance ratios among 12 neutron-capture elements are indicative of r-process nucleosynthesis. Another star is highly enhanced in Sr relative to heavier elements ([Sr/Ba] = +1.21 +/- 0.25). These chemical signatures can all be attributed to massive, low-metallicity stars or their end states. Our results, the first for stars at large radius in Sextans, demonstrate that these stars were formed in chemically inhomogeneous regions, such as those found in ultra-faint dwarf galaxies.

13.SimSpin v2.5.1 -- Constructing synthetic spectral IFU cubes for comparison with observational surveys

Authors:K. E. Harborne, A. Serene, E. J. A. Davies, C. Derkenne, S. Vaughan, A. I. Burdon, C. del P. Lagos, R. McDermid, S. O'Toole, C. Power, A. S. G. Robotham, G. Santucci, R. Tobar

Abstract: In this work, we present a methodology and a corresponding code-base for constructing mock integral field spectrograph (IFS) observations of simulated galaxies in a consistent and reproducible way. Such methods are necessary to improve the collaboration and comparison of observation and theory results, and accelerate our understanding of how the kinematics of galaxies evolve over time. This code, SimSpin, is an open-source package written in R, but also with an API interface such that the code can be interacted with in any coding language. Documentation and individual examples can be found at the open-source website connected to the online repository. SimSpin is already being utilised by international IFS collaborations, including SAMI and MAGPI, for generating comparable data sets from a diverse suite of cosmological hydrodynamical simulations.

14.Continuum Reverberation Mapping of Mrk 876 Over Three Years With Remote Robotic Observatories

Authors:Jake A. Miller, Edward M. Cackett, Michael R. Goad, Keith Horne, Aaron J. Barth, Encarni Romero-Colmenero, Michael Fausnaugh, Jonathan Gelbord, Kirk T. Korista, Hermine Landt, Tommaso Treu, Hartmut Winkler

Abstract: Continuum reverberation mapping probes the sizescale of the optical continuum-emitting region in active galactic nuclei (AGN). Through 3 years of multiwavelength photometric monitoring in the optical with robotic observatories, we perform continuum reverberation mapping on Mrk~876. All wavebands show large amplitude variability and are well correlated. Slow variations in the light curves broaden the cross-correlation function (CCF) significantly, requiring detrending in order to robustly recover interband lags. We measure consistent interband lags using three techniques (CCF, JAVELIN, PyROA), with a lag of around 13~days from $u$ to $z$. These lags are longer than the expected radius of 12~days for the self-gravitating radius of the disk. The lags increase with wavelength roughly following $\lambda^{4/3}$, as would be expected from thin disk theory, but the lag normalization is approximately a factor of 3 longer than expected, as has also been observed in other AGN. The lag in the $i$ band shows an excess which we attribute to variable H$\alpha$ broad-line emission. A flux-flux analysis shows a variable spectrum that follows $f_\nu \propto \lambda^{-1/3}$ as expected for a disk, and an excess in the $i$ band that also points to strong variable H$\alpha$ emission in that band.

1.Reconciling the magnetic field in central disc galaxies with the dynamical mass using the cosmological simulations

Authors:Mohammad Hosseinirad, Fatemeh Tabatabaei, Mojtaba Raouf, Mahmood Roshan

Abstract: The Universe is pervaded by magnetic fields in different scales, although for simplicity, they are ignored in most cosmological simulations. In this paper, we use the TNG50, which is a large cosmological galaxy formation simulation that incorporates magnetic fields with unprecedented resolution. We study the correlation of the magnetic field with various galaxy properties such as the total, stellar and gaseous mass, circular velocity, size and star formation rate. We find a linear correlation between the average magnetic field pervading the disc of galaxies in relative isolation and their circular velocities. In addition we observed that in this sample the average magnetic field in the disc is correlated with the total mass as $\overline{B}\sim M_{\mathrm{tot,\,R_{\star}}}^{0.2}$. We also find that the massive galaxies with active wind-driven black hole feedback, do not follow this trend, as their magnetic field is substantially decreased by this feedback mode. We show that the correlation of the magnetic field with the star formation rate is a little weaker than the circular velocity. Moreover, we compare the magnetic field components of the above sample with a compiled observational sample of non-cluster non-interacting nearby galaxies. Similar to the observation, we find a coupling between the ordered magnetic field and the circular velocity of the flat part of the rotation curve in the simulation, although contrary to the observation, the ordered component is the dominant one in the simulation.

1.Origins of the north-south asymmetry in the ALFALFA HI velocity width function

Authors:Richard A. N. Brooks University College London Durham ICC Durham University, Kyle A. Oman Durham ICC Durham University, Carlos S. Frenk Durham ICC Durham University

Abstract: The number density of extragalactic 21-cm radio sources as a function of their spectral line-widths -- the HI width function (HIWF) -- is a tracer of the dark matter halo mass function. The ALFALFA 21-cm survey measured the HIWF in northern and southern Galactic fields finding a systematically higher number density in the north; an asymmetry which is in tension with $\Lambda$ cold dark matter models which predicts the HIWF should be identical everywhere if sampled in sufficiently large volumes. We use the Sibelius-DARK N-body simulation and semi-analytical galaxy formation model GALFORM to create mock ALFALFA surveys to investigate survey systematics. We find the asymmetry has two origins: the sensitivity of the survey is different in the two fields, and the algorithm used for completeness corrections does not fully account for biases arising from spatial galaxy clustering. Once survey systematics are corrected, cosmological models can be tested against the HIWF.

2.Disk galaxies are self-similar: the universality of the HI-to-Halo mass ratio for isolated disks

Authors:Marie Korsaga, Benoit Famaey, Jonathan Freundlich, Lorenzo Posti, Rodrigo Ibata, Christian Boily, Katarina Kraljic, D. Esparza-Arredondo, C. Ramos Almeida, Jean Koulidiati

Abstract: Observed scaling relations in galaxies between baryons and dark matter global properties are key to shed light on the process of galaxy formation and on the nature of dark matter. Here, we study the scaling relation between the neutral hydrogen (HI) and dark matter mass in isolated rotationally-supported disk galaxies at low redshift. We first show that state-of-the-art galaxy formation simulations predict that the HI-to-dark halo mass ratio decreases with stellar mass for the most massive disk galaxies. We then infer dark matter halo masses from high-quality rotation curve data for isolated disk galaxies in the local Universe, and report on the actual universality of the HI-to-dark halo mass ratio for these observed galaxies. This scaling relation holds for disks spanning a range of 4 orders of magnitude in stellar mass and 3 orders of magnitude in surface brightness. Accounting for the diversity of rotation curve shapes in our observational fits decreases the scatter of the HI-to-dark halo mass ratio while keeping it constant. This finding extends the previously reported discrepancy for the stellar-to-halo mass relation of massive disk galaxies within galaxy formation simulations to the realm of neutral atomic gas. Our result reveals that isolated galaxies with regularly rotating extended HI disks are surprisingly self-similar up to high masses, which hints at mass-independent self-regulation mechanisms that have yet to be fully understood.

3.Streamlined Lensed Quasar Identification in Multiband Images via Ensemble Networks

Authors:Irham Taufik Andika, Sherry H. Suyu, Raoul Cañameras, Alejandra Melo, Stefan Schuldt, Yiping Shu, Anna-Christina Eilers, Anton Timur Jaelani, Minghao Yue

Abstract: Quasars experiencing strong lensing offer unique viewpoints on subjects like the cosmic expansion rate, the dark matter profile within the foreground deflectors, and the quasar host galaxies. Unfortunately, identifying them in astronomical images is challenging since they are overwhelmed by the abundance of non-lenses. To address this, we have developed a novel approach by ensembling cutting-edge convolutional networks (CNNs) -- i.e., ResNet, Inception, NASNet, MobileNet, EfficientNet, and RegNet -- along with vision transformers (ViTs) trained on realistic galaxy-quasar lens simulations based on the Hyper Suprime-Cam (HSC) multiband images. While the individual model exhibits remarkable performance when evaluated against the test dataset, achieving an area under the receiver operating characteristic curve of $>$97.4% and a median false positive rate of 3.1%, it struggles to generalize in real data, indicated by numerous spurious sources picked by each classifier. A significant improvement is achieved by averaging these CNNs and ViTs, resulting in the impurities being downsized by factors up to 40. Subsequently, combining the HSC images with the UKIRT, VISTA, and unWISE data, we retrieve approximately 60 million sources as parent samples and reduce this to 892,609 after employing a photometry preselection to discover $z>1.5$ lensed quasars with Einstein radii of $\theta_\mathrm{E}<5$ arcsec. Afterward, the ensemble classifier indicates 3991 sources with a high probability of being lenses, for which we visually inspect, yielding 161 prevailing candidates awaiting spectroscopic confirmation. These outcomes suggest that automated deep learning pipelines hold great potential in effectively detecting strong lenses in vast datasets with minimal manual visual inspection involved.

4.The truncation of the disk of NGC 4565: Detected up to z=4 kpc, with star formation, and affected by the warp

Authors:Cristina Martinez-Lombilla, Raul Infante-Sainz, Felipe Jimenez-Ibarra, Johan H. Knapen, Ignacio Trujillo, Sebastien Comeron, Alejandro S. Borlaff, Javier Roman

Abstract: Context: The hierarchical model of galaxy formation suggests that galaxies are continuously growing. However, our position inside the Milky Way prevents us from studying the disk edge. Truncations are low surface brightness features located in the disk outskirts of external galaxies. They indicate where the disk brightness abruptly drops and their location is thought to change dynamically. In previous analyses of Milky Way-like galaxies, truncations were detected up to 3 kpc above the mid-plane but whether they remain present beyond that height remains unclear. Aims: Our goal is to determine whether truncations can be detected above 3 kpc height in the Milky Way-like galaxy NGC 4565, thus establishing the actual disk thickness. We also aim to study how the truncation relates to disk properties such as star formation activity or the warp. Methods: We perform a vertical study of the disk of NGC 4565 edge in unprecedented detail. We explore the truncation radius at different heights above/below the disk mid-plane (0<z<8 kpc) and at different wavelengths. We use new ultra-deep optical data ($\mu_{g,\rm{lim}}=30.5$ mag arcsec$^{-2}$; $3 \sigma$ within $10 \times 10$ arcsec$^{2}$ boxes) in the $g$, $r$ and $i$ broad bands, along with near- and far-ultraviolet, H$\alpha$, and \ion{H}{i} observations. Results: We detect the truncation up to 4 kpc in the $g$, $r$ and $i$ ultra-deep bands which is 1 kpc higher than in any previous study for any galaxy. The radial position of the truncation remains constant up to 3 kpc while higher up it is located at a smaller radius. This result is independent of the wavelength but is affected by the presence of the warp. Conclusions: We propose an inside-out growth scenario for the formation of the disk of NGC 4565. Our results point towards the truncation feature being linked to a star-forming threshold and to the onset of the disk warp.

5.An environment-dependent halo mass function as a driver for the early quenching of $z\geq1.5$ cluster galaxies

Authors:Syeda Lammim Ahad, Adam Muzzin, Yannick M. Bahé, Henk Hoekstra

Abstract: Many $z=1.5$ galaxies with a stellar mass ($M_{\star}$) $\geq 10^{10}\,\mathrm{M}_\odot$ are already quenched in both galaxy clusters ($>50$ per cent) and the field ($>20$ per cent), with clusters having a higher quenched fraction at all stellar masses compared to the field. A puzzling issue is that these massive quenched galaxies have stellar populations of similar age in both clusters and the field. This suggests that, despite the higher quenched fraction in clusters, the dominant quenching mechanism for massive galaxies is similar in both environments. In this work, we use data from the cosmological hydrodynamic simulations Hydrangea and EAGLE to test whether the excess quenched fraction of massive galaxies in $z = 1.5$ clusters results from fundamental differences in their halo properties compared to the field. We find that (i) at $10^{10} \leq$ $M_{\star}/\,\mathrm{M}_\odot\leq 10^{11}$, quenched fractions in the redshift range $1.5 < z < 3.5$ are consistently higher for galaxies with higher peak maximum circular velocity of the dark matter halo ($v_{\mathrm{max, peak}}$), and (ii) the distribution of $v_{\mathrm{max, peak}}$ is strongly biased towards higher values for cluster satellites compared to the field centrals. Due to this difference in the halo properties of cluster and field galaxies, secular processes alone may account for (most of) the environmental excess of massive quenched galaxies in high-redshift (proto) clusters. Taken at face value, our results challenge a fundamental assumption of popular quenching models, namely that clusters are assembled from an unbiased subset of infalling field galaxies. If confirmed, this would imply that such models must necessarily fail at high redshift, as indicated by recent observations.

6.Strongly lensed [O III] emitters at Cosmic Noon with Roman: Characterizing extreme emission line galaxies on star cluster complex scales (100 pc)

Authors:Keunho J. Kim UCincinnati, Matthew B. Bayliss UCincinnati, Håkon Dahle UOslo, Taylor Hutchison NASA GSFC, Keren Sharon UMichigan, Guillaume Mahler Durham U, M. Riley Owens UCincinnati, James E. Rhoads NASA GSFC

Abstract: Extreme emission line galaxies (EELGs) are considered the primary contributor to cosmic reionization and are valuable laboratories to study the astrophysics of massive stars. It is strongly expected that Roman's High Latitude Wide Area Survey (HLWAS) will find many strongly gravitationally lensed [O III] emitters at Cosmic Noon (1 < z < 2.8). Roman imaging and grism spectroscopy alone will simultaneously confirm these strong lens systems and probe their interstellar medium (ISM) and stellar properties on small scales ($\lesssim$ 100 pc). Moreover, these observations will synergize with ground-based and space-based follow-up observations of the discovered lensed [O III] emitters in multi-wavelength analyses of their properties (e.g., massive stars and possible escape of ionizing radiation), spatially resolved on the scales of individual star cluster complexes. Only Roman can uniquely sample a large number of lensed [O III] emitters to study the small scale (~ 100 pc) ISM and stellar properties of these extreme emission line galaxies, detailing the key physics of massive stars and the ISM that govern cosmic reionization.

7.Mapping the imprints of stellar and AGN feedback in the circumgalactic medium with X-ray microcalorimeters

Authors:Gerrit Schellenberger, Ákos Bogdán, John A. ZuHone, Benjamin D. Oppenheimer, Nhut Truong, Ildar Khabibullin, Fred Jennings, Annalisa Pillepich, Joseph Burchett, Christopher Carr, Priyanka Chakraborty, Robert Crain, William Forman, Christine Jones, Caroline A. Kilbourne, Ralph P. Kraft, Maxim Markevitch, Daisuke Nagai, Dylan Nelson, Anna Ogorzalek, Scott Randall, Arnab Sarkar, Joop Schaye, Sylvain Veilleux, Mark Vogelsberger, Q. Daniel Wang, Irina Zhuravleva

Abstract: The Astro2020 Decadal Survey has identified the mapping of the circumgalactic medium (CGM, gaseous plasma around galaxies) as a key objective. We explore the prospects for characterizing the CGM in and around nearby galaxy halos with future large grasp X-ray microcalorimeters. We create realistic mock observations from hydrodynamical simulations (EAGLE, IllustrisTNG, and Simba) that demonstrate a wide range of potential measurements, which will address the open questions in galaxy formation and evolution. By including all background and foreground components in our mock observations, we show why it is impossible to perform these measurements with current instruments, such as X-ray CCDs, and only microcalorimeters will allow us to distinguish the faint CGM emission from the bright Milky Way (MW) foreground emission lines. We find that individual halos of MW mass can, on average, be traced out to large radii, around R500, and for larger galaxies even out to R200, using the OVII, OVIII, or FeXVII emission lines. Furthermore, we show that emission line ratios for individual halos can reveal the radial temperature structure. Substructure measurements show that it will be possible to relate azimuthal variations to the feedback mode of the galaxy. We demonstrate the ability to construct temperature, velocity, and abundance ratio maps from spectral fitting for individual galaxy halos, which reveal rotation features, AGN outbursts, and enrichment.

8.Can cuspy dark matter dominated halos hold cored stellar mass distributions?

Authors:Jorge Sanchez Almeida Instituto de Astrofisica de Canarias, La Laguna, Spain Astrophysics Department, Universidad de La Laguna, Angel R. Plastino CeBio y Departamento de Ciencias Basicas, Universidad Nacional del Noroeste de la Prov. de Buenos Aires, UNNOBA, CONICET, Junin, Argentina, Ignacio Trujillo Instituto de Astrofisica de Canarias, La Laguna, Spain Astrophysics Department, Universidad de La Laguna

Abstract: According to the current concordance cosmological model, the dark matter (DM) particles are collision-less and produce self-gravitating structures with a central cusp which, generally, is not observed. The observed density tends to a central plateau or core, explained within the cosmological model through the gravitational feedback of baryons on DM. This mechanism becomes inefficient when decreasing the galaxy stellar mass so that in the low-mass regime (Mstar << 10**6 Msun) the energy provided by the baryons is insufficient to modify cusps into cores. Thus, if cores exist in these galaxies they have to reflect departures from the collision-less nature of DM. Measuring the DM mass distribution in these faint galaxies is extremely challenging, however, their stellar mass distribution can be characterized through deep photometry. Here we provide a way of using only the stellar mass distribution to constrain the underlying DM distribution. The so-called Eddington inversion method allows us to discard pairs of stellar distributions and DM potentials requiring (unphysical) negative distribution functions in the phase space. In particular, cored stellar density profiles are incompatible with the Navarro, Frenk, and White (NFW) potential expected from collision-less DM if the velocity distribution is isotropic and the system spherically symmetric. Through a case-by-case analysis, we are able to relax these assumptions to consider anisotropic velocity distributions and systems which do not have exact cores. In general, stellar distributions with radially biased orbits are difficult to reconcile with NFW-like potentials, and cores in the baryon distribution tend to require cores in the DM distribution.

9.ReveaLLAGN 0: First Look at JWST MIRI data of Sombrero and NGC 1052

Authors:K. Goold U of Utah, A. Seth U of Utah, M. Molina U of Utah, D. Ohlson U of Utah, J. C. Runnoe Vanderbilt U, T. Boeker ESA/ STScI, T. A. Davis Cardiff U, A. Dumont MPIA, M. Eracleous Penn State U, J. A. Fernández-Ontiveros INAF-IAPS, E. Gallo U of Michigan, A. D. Goulding Princeton, J. E. Greene Princeton, L. C. Ho Peking U, S. B. Markoff U of Amsterdam, N. Neumayer MPIA, R. Plotkin U of Nevada, A. Prieto IAC, S. Satyapal George Mason U, G. Van De Ven U of Vienna, J. L. Walsh TAMU, F. Yuan CAS, A. Feldmeier-Krause MPIA, K. Gültekin U of Michigan, S. Hoenig U of Southampton, A. Kirkpatrick University of Kansas, N. Lützgendorf ESA/ STScI, A. E. Reines Montana State U, J. Strader Michigan State U, J. R. Trump U of Connecticut, K. T. Voggel U of Strasbourg

Abstract: We present the first results from the Revealing Low-Luminosity Active Galactic Nuclei (ReveaLLAGN) survey, a JWST survey of seven nearby LLAGN. We focus on two observations with the Mid-Infrared Instrument's (MIRI) Medium Resolution Spectrograph (MRS) of the nuclei of NGC 1052 and Sombrero (NGC 4594 / M104). We also compare these data to public JWST data of a higher-luminosity AGN, NGC 7319. JWST clearly resolves the AGN component even in Sombrero, the faintest target in our survey; the AGN components have very red spectra. We find that the emission-line widths in both NGC 1052 and Sombrero increase with increasing ionization potential, with FWHM > 1000 km/s for lines with ionization potential > 50 eV. These lines are also significantly blue-shifted in both LLAGN. The high ionization potential lines in NGC 7319 show neither broad widths or significant blue shifts. Many of the lower ionization potential emission lines in Sombrero show significant blue wings extending > 1000 km/s. These features and the emission-line maps in both galaxies are consistent with outflows along the jet direction. Sombrero has the lowest luminosity high-ionization potential lines ([Ne V] and [O IV]) ever measured in the mid-IR, but the relative strengths of these lines are consistent with higher luminosity AGN. On the other hand, the [Ne V] emission is much weaker relative to the [Ne III}] and [Ne II] lines of higher-luminosity AGN. These initial results show the great promise that JWST holds for identifying and studying the physical nature of LLAGN.

10.Properties of the Line-of-Sight Velocity Field in the Hot and X-ray Emitting Circumgalactic Medium of Nearby Simulated Disk Galaxies

Authors:J. A. ZuHone CfA, G. Schellenberger CfA, A. Ogorzalek NASA/GSFC U. Maryland-College Park, B. D. Oppenheimer U. Colorado, J. Stern Tel Aviv University, A. Bogdan CfA, N. Truong NASA/GSFC U. Maryland-Baltimore County MPIA, M. Markevitch NASA/GSFC, A. Pillepich MPIA, D. Nelson U. Heidelberg, J. N. Burchett New Mexico State University, I. Khabibullin Ludwig-Maximilians-Universitat Munich Space Research Institute MPA, C. A. Kilbourne NASA/GSFC, R. P. Kraft CfA, P. E. J. Nulsen CfA University of Western Australia, S. Veilleux U. Maryland-College Park, M. Vogelsberger MIT, Q. D. Wang U. Massachusetts-Amherst, I. Zhuravleva U. Chicago

Abstract: The hot, X-ray-emitting phase of the circumgalactic medium in galaxies is believed to be the reservoir of baryons from which gas flows onto the central galaxy and into which feedback from AGN and stars inject mass, momentum, energy, and metals. These effects shape the velocity fields of the hot gas, which can be observed by X-ray IFUs via the Doppler shifting and broadening of emission lines. In this work, we analyze the gas kinematics of the hot circumgalactic medium of Milky Way-mass disk galaxies from the TNG50 simulation with synthetic observations to determine how future instruments can probe this velocity structure. We find that the hot phase is often characterized by outflows outward from the disk driven by feedback processes, radial inflows near the galactic plane, and rotation, though in other cases the velocity field is more disorganized and turbulent. With a spectral resolution of $\sim$1 eV, fast and hot outflows ($\sim$200-500 km s$^{-1}$) can be measured, depending on the orientation of the galaxy on the sky. The rotation velocity of the hot phase ($\sim$100-200 km s$^{-1}$) can be measured using line shifts in edge-on galaxies, and is slower than that of colder gas phases but similar to stellar rotation velocities. By contrast, the slow inflows ($\sim$50-100 km s$^{-1}$) are difficult to measure in projection with these other components. We find that the velocity measured is sensitive to which emission lines are used. Measuring these flows will help constrain theories of how the gas in these galaxies forms and evolves.

11.EIGER IV: The cool 10$^4$K circumgalactic environment of high-$z$ galaxies reveals remarkably efficient IGM enrichment

Authors:Rongmon Bordoloi, Robert A. Simcoe, Jorryt Matthee, Daichi Kashino, Ruari Mackenzie, Simon J. Lilly, Anna-Christina Eilers, Bin Liu, David DePalma, Minghao Yue, Rohan P. Naidu

Abstract: We report new observations of the cool diffuse gas around 29, $2.3<z<6.3$ galaxies, using deep JWST/NIRCam slitless grism spectroscopy around the sightline to the quasar J0100+2802. The galaxies span a stellar mass range of $7.1 \leq \log M_{*}/M_{sun} \leq 10.7$, and star-formation rates of $-0.1 < \log \; SFR/M_{sun}yr^{-1} \; <2.3$. We find galaxies for seven MgII absorption systems within 300 kpc of the quasar sightline. The MgII radial absorption profile falls off sharply with radii, with most of the absorption extending out to 2-3$R_{200}$ of the host galaxies. Six out of seven MgII absorption systems are detected around galaxies with $\log M_{*}/M_{sun} >$9. MgII absorption kinematics are shifted from the systemic redshift of host galaxies with a median absolute velocity of 135 km/s and standard deviation of 85 km/s. The high kinematic offset and large radial separation ($R> 1.3 R_{200}$), suggest that five out of the seven MgII absorption systems are gravitationally not bound to the galaxies. In contrast, most cool circumgalactic media at $z<1$ are gravitationally bound. The high incidence of unbound MgII gas in this work suggests that towards the end of reionization, galaxy halos are in a state of remarkable disequilibrium, and are highly efficient in enriching the intergalactic medium. Two strongest MgII absorption systems are detected at $z\sim$ 4.22 and 4.5, the former associated with a merging galaxy system and the latter associated with three kinematically close galaxies. Both these galaxies reside in local galaxy over-densities, indicating the presence of cool MgII absorption in two "proto-groups" at $z>4$.

12.Fly-by galaxy encounters with multiple black holes produce star-forming linear wakes

Authors:Nianyi Chen, Patrick LaChance, Yueying Ni, Tiziana Di Matteo, Rupert Croft, Priyamvada Natarajan, Simeon Bird

Abstract: We look for simulated star-forming linear wakes such as the one recently discovered by van Dokkum et al. (2023) in the cosmological hydrodynamical simulation ASTRID. Amongst the runaway black holes in ASTRID, none are able to produce clear star-forming wakes. Meanwhile, fly-by encounters, typically involving a compact galaxy (with a central black hole) and a star-forming galaxy (with a duo of black holes) reproduce remarkably well many of the key properties (its length and linearity; recent star formation, etc.) of the observed star-forming linear feature. We predict the feature to persist for approximately 100 Myr in such a system and hence constitute a rare event. The feature contains a partly stripped galaxy (with $M_{\rm gal}=10^9 \sim 10^{10}M_\odot$) and a dual BH system ($M_{\rm BH}=10^5 \sim 10^7\,M_\odot$) in its brightest knot. X-ray emission from AGN in the knot should be detectable in such systems. After $100\sim 200\,{\rm Myrs}$ from the first fly-by, the galaxies merge leaving behind a triple black hole system in a (still) actively star-forming early-type remnant of mass $\sim 5\times 10^{10}\,M_\odot$. Follow-up JWST observations may be key for revealing the nature of these linear features by potentially detecting the older stellar populations constituting the bright knot. Confirmation of such detections may therefore help discriminate a fly-by encounter from a massive BH wake to reveal the origin of such features.

13.X-ray metal line emission from the hot circumgalactic medium: probing the effects of supermassive black hole feedback

Authors:Nhut Truong, Annalisa Pillepich, Dylan Nelson, Ákos Bogdán, Gerrit Schellenberger, Priyanka Chakraborty, William R. Forman, Ralph Kraft, Maxim Markevitch, Anna Ogorzalek, Benjamin D. Oppenheimer, Arnab Sarkar, Sylvain Veilleux, Mark Vogelsberger, Q. Daniel Wan, Norbert Werner, Irina Zhuravleva, John Zuhone

Abstract: We derive predictions from state-of-the-art cosmological galaxy simulations for the spatial distribution of the hot circumgalactic medium (CGM, ${\rm [0.1-1]R_{200c}}$) through its emission lines in the X-ray soft band ($[0.3-1.3]$ keV). In particular, we compare IllustrisTNG, EAGLE, and SIMBA and focus on galaxies with stellar mass $10^{10-11.6}\, \MSUN$ at $z=0$. The three simulation models return significantly different surface brightness radial profiles of prominent emission lines from ionized metals such as OVII(f), OVIII, and FeXVII as a function of galaxy mass. Likewise, the three simulations predict varying azimuthal distributions of line emission with respect to the galactic stellar planes, with IllustrisTNG predicting the strongest angular modulation of CGM physical properties at radial range ${\gtrsim0.3-0.5\,R_{200c}}$. This anisotropic signal is more prominent for higher-energy lines, where it can manifest as X-ray eROSITA-like bubbles. Despite different models of stellar and supermassive black hole (SMBH) feedback, the three simulations consistently predict a dichotomy between star-forming and quiescent galaxies at the Milky-Way and Andromeda mass range, where the former are X-ray brighter than the latter. This is a signature of SMBH-driven outflows, which are responsible for quenching star formation. Finally, we explore the prospect of testing these predictions with a microcalorimeter-based X-ray mission concept with a large field-of-view. Such a mission would probe the extended hot CGM via soft X-ray line emission, determine the physical properties of the CGM, including temperature, from the measurement of line ratios, and provide critical constraints on the efficiency and impact of SMBH feedback on the CGM.

14.Metallicity Dependence of Molecular Cloud Hierarchical Structure at Early Evolutionary Stages

Authors:Masato I. N. Kobayashi, Kazunari Iwasaki, Kengo Tomida, Tsuyoshi Inoue, Kazuyuki Omukai, Kazuki Tokuda

Abstract: The formation of molecular clouds out of HI gas is the first step toward star formation. Its metallicity dependence plays a key role to determine star formation through the cosmic history. Previous theoretical studies with detailed chemical networks calculate thermal equilibrium states and/or thermal evolution under one-zone collapsing background. The molecular cloud formation in reality, however, involves supersonic flows, and thus resolving the cloud internal turbulence/density structure in three dimension is still essential. We here perform magnetohydrodynamics simulations of 20 km s^-1 converging flows of Warm Neutral Medium (WNM) with 1 uG mean magnetic field in the metallicity range from the Solar (1.0 Zsun) to 0.2 Zsun environment. The Cold Neutral Medium (CNM) clumps form faster with higher metallicity due to more efficient cooling. Meanwhile, their mass functions commonly follow dn/dm proportional to m^-1.7 at three cooling times regardless of the metallicity. Their total turbulence power also commonly shows the Kolmogorov spectrum with its 80 percent in the solenoidal mode, while the CNM volume alone indicates the transition towards the Larson's law. These similarities measured at the same time in the unit of the cooling time suggest that the molecular cloud formation directly from the WNM alone requires a longer physical time in a lower metallicity environment in the 1.0-0.2 Zsun range. To explain the rapid formation of molecular clouds and subsequent massive star formation possibly within 10 Myr as observed in the Large/Small Magellanic Clouds (LMC/SMC), the HI gas already contains CNM volume instead of pure WNM.

15.Winds versus jets: a comparison between black hole feedback modes in simulations of idealized galaxy groups and clusters

Authors:Filip Huško ICC, Durham University, Cedric G. Lacey ICC, Durham University, Joop Schaye Leiden Observatory, Folkert S. J. Nobels Leiden Observatory, Matthieu Schaller Leiden Observatory Lorentz Institute for Theoretical Physics, Leiden

Abstract: Using the SWIFT simulation code we study different forms of active galactic nuclei (AGN) feedback in idealized galaxy groups and clusters. We first present a physically motivated model of black hole (BH) spin evolution and a numerical implementation of thermal isotropic feedback (representing the effects of energy-driven winds) and collimated kinetic jets that they launch at different accretion rates. We find that kinetic jet feedback is more efficient at quenching star formation in the brightest cluster galaxies (BCGs) than thermal isotropic feedback, while simultaneously yielding cooler cores in the intracluster medium (ICM). A hybrid model with both types of AGN feedback yields moderate star formation rates, while having the coolest cores. We then consider a simplified implementation of AGN feedback by fixing the feedback efficiencies and the jet direction, finding that the same general conclusions hold. We vary the feedback energetics (the kick velocity and the heating temperature), the fixed efficiencies and the type of energy (kinetic versus thermal) in both the isotropic and the jet case. The isotropic case is largely insensitive to these variations. In particular, we highlight that kinetic isotropic feedback (used e.g. in IllustrisTNG) is similar in its effects to its thermal counterpart (used e.g. in EAGLE). On the other hand, jet feedback must be kinetic in order to be efficient at quenching. We also find that it is much more sensitive to the choice of energy per feedback event (the jet velocity), as well as the efficiency. The former indicates that jet velocities need to be carefully chosen in cosmological simulations, while the latter motivates the use of BH spin evolution models.

1.Ghostly galaxies: accretion-dominated stellar systems in low-mass dark matter halos

Authors:Chung-Wen Wang, Andrew P. Cooper, Sownak Bose, Carlos S. Frenk, Wojciech A. Hellwing

Abstract: Wide-area deep imaging surveys have discovered large numbers of extremely low surface brightness dwarf galaxies, which challenge galaxy formation theory and, potentially, offer new constraints on the nature of dark matter. Here we discuss one as-yet unexplored formation mechanism that may account for a fraction of low surface brightness dwarfs. We call this the `ghost galaxy' scenario. In this scenario, inefficient radiative cooling prevents star formation in the `main branch' of the merger tree of a low mass dark matter halo, such that almost all its stellar mass is acquired through mergers with less massive (but nevertheless star-forming) progenitors. Present-day systems formed in this way would be `ghostly' isolated stellar halos with no central galaxy. We use merger trees based on the Extended Press-Schechter formalism and the COCO cosmological N-body simulation to demonstrate that mass assembly histories of this kind can occur for low-mass halos in Lambda-CDM, but they are rare. They are most probable in isolated halos of present-day mass ~4x10^9 M_sun, occurring for ~5 per cent of all halos of that mass under standard assumptions about the timing and effect of cosmic reionization. The stellar masses of star-forming progenitors in these systems are highly uncertain; abundance-matching arguments imply a bimodal present-day mass function having a brighter population (median M_star ~3x10^6 M_sun) consistent with the tail of the observed luminosity function of ultra-diffuse galaxies. This suggests observable analogues of these systems may await discovery. We find that a stronger ionizing background (globally or locally) produces brighter and more extended ghost galaxies.

2.The precession and inclinational variation across the plane of the Milky Way revealed by open clusters

Authors:Zhihong He

Abstract: This article presents a study of the geometry and motion of the Galactic disk using open clusters in the Gaia era. The findings suggest that the inclination angle of the Galactic disk increases gradually from the inner to the outer disk, with a shift in orientation at the Galactocentric radius of approximately 5 to 7 kpc. Furthermore, the study reveals that the inclined orbits may be elliptical rather than circular, however, more observations are needed to confirm this. An analysis of the vertical motion along the Galactocentric radius reveals that the disk has warped with precession, and that the line-of-nodes shifts at different radii, aligning with the results from the classical Cepheids. Although there is uncertainty for precession/peculiar motion in Solar orbit, after considering the uncertainty, the study derives a median value of precession rate = 6.8 km/s/kpc in the Galaxy. This value for the derived precession in the outer disk is lower than those in the literature due to the systematic motion in Solar orbit (inclination angle = 0.6 deg). The study also finds that the inclinational variation of the disk is significant and can cause systematic motion, with the inclinational variation rate decreasing along the Galactic radius with a slope of -8.9 uas/yr/kpc. Moreover, the derived inclinational variation rate in Solar orbit is 59.1+-11.2(sample)+-7.7(VZsun) uas/yr, which makes it observable for high precision astrometry.

3.From binary to singular: the AGN PSO J334.2028+1.4075 under the high-resolution scope

Authors:P. Benke, K. É. Gabányi, S. Frey, T. An, L. I. Gurvits, E. Kun, P. Mohan, Z. Paragi, E. Ros

Abstract: PSO J334.2028+1.4075 (PSO J334) is a luminous quasar located at redshift z=2.06. The source gained attention when periodic flux density variations were discovered in its optical light curve. These variations were initially interpreted as the variability due to the orbital motion of a supermassive black hole binary (SMBHB) residing in a single circumbinary accretion disk. However, subsequent multiwavelength observations provided evidence against the binary hypothesis as no optical periodicity was found on extended time baselines. On the other hand, detailed radio analysis with the Karl G. Jansky Very Large Array (VLA) and the Very Long Baseline Array (VLBA) revealed a lobe-dominated quasar at kpc scales, and possibly a precessing jet, which could retain PSO J334 as a binary SMBH candidate. We aim to study both the large- and small-scale radio structures in PSO J334 to provide additional evidence for or against the binary scenario. We observed the source at 1.7 GHz with the European Very Long Baseline Interferometry Network (EVN), and at 1.5 and 6.2 GHz with the VLA, at frequencies that complement the previous radio interferometric study. Our images reveal a single component at parsec scales slightly resolved in the southeast-northwest direction and a lobe-dominated quasar at kiloparsec scales with a complex structure. The source morphology and polarization in our VLA maps suggest that the jet is interacting with dense clumps of the ambient medium. While we also observe a misalignment between the inner jet and the outer lobes, we suggest that this is due to the restarted nature of the radio jet activity and the possible presence of a warped accretion disk rather than due to the perturbing effects of a companion SMBH. Our analysis suggests that PSO J334 is most likely a jetted AGN with a single SMBH, and there is no clear evidence of a binary SMBH system in its central engine.

4.Initial sizes of star clusters: implications for cluster dissolution during galaxy evolution

Authors:Marta Reina-Campos, Alison Sills, Godefroy Bichon

Abstract: Massive star clusters are often used as tracers of galaxy formation and assembly. In order to do so, we must understand their properties at formation, and how those properties change with time, galactic environment, and galaxy assembly history. The two most important intrinsic properties that govern star cluster evolution are mass and radius. In this paper, we investigate 10 theoretically and observationally motivated initial size-mass relations for star clusters, and evolve populations of clusters through galaxy formation models. We compare our results to each other and to observations of cluster populations in M83, M31, and the Milky Way. We find that none of our size-mass relations agree with the observations after 6-10 Gyr of evolution. We can successfully reproduce the cluster mass functions with models that have a small range of initial radii, and which do not allow cluster radii to change with time. However, these models do not agree with our understanding of cluster evolution, which does involve radius evolution, and do not match the observed distributions of radii. We note that there is a region of parameter space where clusters are optimally protected from both tidal shocks and evaporation due to two-body relaxation. Clusters which are allowed to evolve into this parameter space will likely survive. An improved understanding of both mass and radius evolution of star clusters in realistic, time-varying galactic potentials is necessary to appropriately make the connection between present-day cluster properties and their use as tracers of galaxy formation and assembly.

5.Deep Search for Glycine Conformers in Barnard 5

Authors:Tadeus Carl, Eva Wirström, Per Bergman, Steven Charnley, Yo-Ling Chuang, Yi-Jehng Kuan

Abstract: One of the most fundamental hypotheses in astrochemistry and astrobiology states that crucial biotic molecules like glycine (NH$_2$CH$_2$COOH) found in meteorites and comets are inherited from early phases of star formation. Most observational searches for glycine in the interstellar medium have focused on warm, high-mass molecular cloud sources. However, recent studies suggest that it might be appropriate to shift the observational focus to cold, low-mass sources. We aim to detect glycine towards the so-called methanol hotspot in the Barnard 5 dark cloud. The hotspot is a cold source ($T_\mathrm{gas}\approx 7.5$ K) with yet high abundances of complex organic molecules (COMs) and water in the gas phase. We carried out deep, pointed observations with the Onsala 20m telescope, targeting several transitions of glycine conformers I and II (Gly-I and Gly-II) in the frequency range $70.2$-$77.9$ GHz. No glycine lines are detected towards the targeted position, but we use a line stacking procedure to derive sensitive abundance upper limits w.r.t. H$_2$ for Gly-I and Gly-II, i.e. $\leq(2$-$5)\times10^{-10}$ and $\leq(0.7$-$3)\times10^{-11}$, respectively. The obtained Gly-II upper limits are the most stringent for a cold source, while the Gly-I upper limits are mostly on the same order as previously measured limits. The measured abundances w.r.t. H$_2$ of other COMs at the B5 methanol hotspot range from $2\times10^{-10}$ (acetaldehyde) to $2\times10^{-8}$ (methanol). Hence, based on a total glycine upper limit of $(2$-$5)\times10^{-10}$, we cannot rule out that glycine is present but undetected.

6.Quaia, the Gaia-unWISE Quasar Catalog: An All-Sky Spectroscopic Quasar Sample

Authors:Kate Storey-Fisher, David W. Hogg, Hans-Walter Rix, Anna-Christina Eilers, Giulio Fabbian, Michael Blanton, David Alonso

Abstract: We present a new, all-sky quasar catalog, Quaia, that samples the largest comoving volume and has the cleanest selection function of any existing spectroscopic quasar sample. The catalog draws on the 6,649,162 quasar candidates identified by the Gaia mission that have redshift estimates from the space observatory's low-resolution BP/RP spectra. This initial sample is highly homogeneous and complete, but has low purity, and 18% of even the bright ($G<20.0$) confirmed quasars have discrepant redshift estimates ($|\Delta z/(1+z)| > 0.2$) compared to those from the Sloan Digital Sky Survey (SDSS). In this work, we combine the Gaia candidates with unWISE infrared data (based on the Wide-field Infrared Survey Explorer survey) to construct a catalog useful for cosmological and astrophysical quasar studies. We apply cuts based on proper motions and Gaia and unWISE colors, reducing the number of contaminants by $\sim$4$\times$. We improve the redshifts by training a $k$-nearest neighbors model on colors and Gaia redshift estimates and using SDSS redshift labels, and achieve redshift estimates on the $G<20.0$ sample with only 6% (10%) catastrophic errors with $|\Delta z/(1+z)| > 0.2$ ($0.1$), a reduction of $\sim$3$\times$ ($\sim$2$\times$) compared to the Gaia redshifts. The final catalog has 1,295,502 quasars with a $G<20.5$, and 755,850 candidates in an even cleaner $G<20.0$ sample. We also construct a rigorous all-sky selection function model for the catalog. We compare Quaia to existing quasar catalogs, in particular showing that its large effective volume makes it a highly competitive sample for cosmological large-scale structure analyses. The catalog is publicly available at

7.On the Tremaine-Weinberg method: how much can we trust gas tracers to measure pattern speeds?

Authors:Olga Borodina, Thomas G. Williams, Mattia C. Sormani, Sharon Meidt, Eva Schinnerer

Abstract: Pattern speeds are a fundamental parameter of the dynamical features (e.g. bars, spiral arms) of a galaxy, setting resonance locations. Pattern speeds are not directly observable, so the Tremaine-Weinberg (TW) method has become the most common method used to measure them in galaxies. However, it has not been tested properly whether this method can straightforwardly be applied to gas tracers, despite this being widely done in the literature. When applied to observations, the TW method may return invalid results, which are difficult to diagnose due to a lack of ground truth for comparison. Although some works applying the TW method to simulated galaxies exist, only stellar populations have been tested. Therefore, here we explore the applicability of the TW method for gas gracers, by applying it to hydrodynamical simulations of galaxies, where we know the true value of the bar pattern speed. We perform some simple tests to see if the TW method has a physically reasonable output. We add different kinds of uncertainties (e.g. in position angle or flux) to the data to mock observational errors based on the magnitude of uncertainty present in the observations. Second, we test the method on 3D simulations with chemical networks. We show that in general, applying TW to observations of gas will not recover the true pattern speed. These results have implications for many "pattern speeds" reported in the literature, and based on these tests we also give some best practices for measuring pattern speeds using gas tracers going forwards.

8.Stellar halo striations from assumptions of axisymmetry

Authors:Elliot Y. Davies, Adam M. Dillamore, Vasily Belokurov, N. Wyn Evans

Abstract: Motivated by the LMC's impact on the integral of motion space of the stellar halo, we run an $N$-body merger simulation to produce a population of halo-like stars. We subsequently move to a test particle simulation, in which the LMC perturbs this debris. When an axisymmetric potential is assumed for the final snapshot of the $N$-body merger remnant, a series of vertical striations in $(L_z, E)$ space form as the LMC approaches its pericentre. These result from the formation of overdensities in angular momentum owing to a relationship between the precession rate of near radial orbits and the torquing of these orbits by the LMC. This effect is heavily dependent on the shape of the inner potential. If a quadrupole component of the potential is included these striations become significantly less apparent due to the difference in precession rate between the two potentials. The absence of these features in data, and the dramatic change in orbital plane precession rate, discourages the use of an axisymmetric potential for highly eccentric orbits accreted from a massive GSE-like merger. Given the link between appearance of these striations and the shape of the potential, this effect may provide a new method of constraining the axisymmetry of the halo.

9.Modeling the High-Energy Ionizing Output from Simple Stellar and X-ray Binary Populations

Authors:Kristen Garofali, Antara R. Basu-Zych, Benjamin D. Johnson, Panayiotis Tzanavaris, Anne Jaskot, Chris Richardson, Bret D. Lehmer, Mihoko Yukita, Edmund Hodges-Kluck, Ann Hornschemeier, Andrew Ptak, Neven Vulic

Abstract: We present a methodology for modeling the joint ionizing impact due to a ``simple X-ray population" (SXP) and its corresponding simple stellar population (SSP), where ``simple" refers to a single age and metallicity population. We construct composite spectral energy distributions (SEDs) including contributions from ultra-luminous X-ray sources (ULXs) and stars, with physically meaningful and consistent consideration of the relative contributions of each component as a function of instantaneous burst age and stellar metallicity. These composite SEDs are used as input for photoionization modeling with Cloudy, from which we produce a grid for the time- and metallicity-dependent nebular emission from these composite populations. We make the results from the photoionization simulations publicly available. We find that the addition of the SXP prolongs the high-energy ionizing output from the population, and correspondingly increases the intensity of nebular lines such as He II $\lambda$1640,4686, [Ne V] $\lambda$3426,14.3$\mu$m, and [O IV] 25.9$\mu$m by factors of at least two relative to models without an SXP spectral component. This effect is most pronounced for instantaneous bursts of star formation on timescales $>$ 10 Myr and at low metallicities ($\sim$ 0.1 $Z_{\odot}$), due to the imposed time- and metallicity-dependent behavior of the SXP relative to the SSP. We propose nebular emission line diagnostics accessible with JWST suitable for inferring the presence of a composite SXP + SSP, and discuss how the ionization signatures compare to models for sources such as intermediate mass black holes.

10.The incidence of AGN in galaxies with different stellar population ages

Authors:Q. Ni, J. Aird, A. Merloni, K. L. Birchall, J. Buchner, M. Salvato, G. Yang

Abstract: It has been argued that recycled gas from stellar mass loss in galaxies might serve as an important fuelling source for black holes (BHs) in their centers. Utilizing spectroscopic samples of galaxies from the Sloan Digital Sky Survey (SDSS) at $z = 0-0.35$ and the Large Early Galaxy Astrophysics Census (LEGA-C) survey at $z = 0.6-1$ that have X-ray coverage from XMM-Newton or Chandra, we test this stellar mass loss fuelling scenario by investigating how AGN activity and BH growth vary with the break strength at 4000 $\r{A}$, $\rm D_{n}4000$ (which is closely related to the age of stellar populations), as younger galaxies are considered to have higher stellar mass loss rates. We found that when controlling for host-galaxy properties, the fraction of log $L_{\rm X}$/$M_\star$ > 32 (which roughly corresponds to Eddington ratios $\gtrsim 1$%) AGN and sample-averaged black hole accretion rate ($\rm \overline{BHAR}$) decrease with $\rm D_{n}4000$ among $\rm D_{n}4000$ $\lesssim$ 1.9 galaxies, suggesting a higher level of AGN activity among younger galaxies, which supports the stellar mass loss fuelling scenario. For the oldest and most massive galaxies at $z = 0-0.35$, this decreasing trend is not present anymore. We found that, among these most massive galaxies at low redshift, the fraction of low specific-accretion-rate (31 $<$ log $L_{\rm X}$/$M_\star$ $<$ 32) AGNs increases with $\rm D_{n}4000$, which may be associated with additional fuelling from hot halo gas and/or enhanced accretion capability.

11.Does God play dice with star clusters?

Authors:Michael Y. Grudić, Stella S. R. Offner, Dávid Guszejnov, Claude-André Faucher-Giguère, Philip F. Hopkins

Abstract: When a detailed model of a stellar population is unavailable, it is most common to assume that stellar masses are independently and identically distributed according to some distribution: the universal initial mass function (IMF). However, stellar masses resulting from causal, long-ranged physics cannot be truly random and independent, and the IMF may vary with environment. To compare stochastic sampling with a physical model, we run a suite of 100 STARFORGE radiation magnetohydrodynamics simulations of low-mass star cluster formation in $2000M_\odot$ clouds that form $\sim 200$ stars each on average. The stacked IMF from the simulated clouds has a sharp truncation at $\sim 28 M_\odot$, well below the typically-assumed maximum stellar mass $M_{\rm up} \sim 100-150M_\odot$ and the total cluster mass. The sequence of star formation is not totally random: massive stars tend to start accreting sooner and finish later than the average star. However, final cluster properties such as maximum stellar mass and total luminosity have a similar amount of cloud-to-cloud scatter to random sampling. Therefore stochastic sampling does not generally model the stellar demographics of a star cluster as it is forming, but may describe the end result fairly well, if the correct IMF -- and its environment-dependent upper cutoff -- are known.

12.Structure, Kinematics, and Observability of the Large Magellanic Cloud's Dynamical Friction Wake in Cold vs. Fuzzy Dark Matter

Authors:Hayden R. Foote, Gurtina Besla, Philip Mocz, Nicolás Garavito-Camargo, Lachlan Lancaster, Martin Sparre, Emily C. Cunningham, Mark Vogelsberger, Facundo A. Gómez, Chervin F. P. Laporte

Abstract: The Large Magellanic Cloud (LMC) will induce a dynamical friction (DF) wake on infall to the Milky Way (MW). The MW's stellar halo will respond to the gravity of the LMC and the dark matter (DM) wake, forming a stellar counterpart to the DM wake. This provides a novel opportunity to constrain the properties of the DM particle. We present a suite of high-resolution, windtunnel-style simulations of the LMC's DF wake that compare the structure, kinematics, and stellar tracer response of the DM wake in cold DM (CDM), with and without self-gravity, vs. fuzzy DM (FDM) with $m_a = 10^{-23}$ eV. We conclude that the self-gravity of the DM wake cannot be ignored. Its inclusion raises the wake's density by $\sim 10\%$, and holds the wake together over larger distances ($\sim$ 50 kpc) than if self-gravity is ignored. The DM wake's mass is comparable to the LMC's infall mass, meaning the DM wake is a significant perturber to the dynamics of MW halo tracers. An FDM wake is more granular in structure and is $\sim 20\%$ dynamically colder than a CDM wake, but with comparable density. The granularity of an FDM wake increases the stars' kinematic response at the percent level compared to CDM, providing a possible avenue of distinguishing a CDM vs. FDM wake. This underscores the need for kinematic measurements of stars in the stellar halo at distances of 70-100 kpc.

13.A study of extreme CIII]1908 & [OIII]88/[CII]157 emission in Pox 186: implications for JWST+ALMA (FUV+FIR) studies of distant galaxies

Authors:Nimisha Kumari, Renske Smit, Claus Leitherer, Joris Witstok, Mike J Irwin, Marco Sirianni, Alessandra Aloisi

Abstract: Carbon spectral features are ubiquitous in the ultraviolet (UV) and far-infrared (FIR) spectra of galaxies in the epoch of reionization (EoR). We probe the ionized carbon content of a blue compact dwarf galaxy Pox 186 using the UV, optical, mid-infrared and FIR data taken with telescopes in space (Hubble, Spitzer, Herschel) and on the ground (Gemini). This local (z~0.0040705) galaxy is likely an analogue of EoR galaxies, as revealed by its extreme FIR emission line ratio, [OIII] 88/[CII] 157 (>10). The UV spectra reveal extreme CIII] 1907, 1909 emission with the strongest equivalent width (EW) = 35.85 $\pm$ 0.73 \AA detected so far in the local (z~0) Universe, a relatively strong CIV 1548, 1550 emission with EW = 7.95 $\pm$0.45\AA, but no He II 1640 detection. Several scenarios are explored to explain the high EW of carbon lines, including high effective temperature, high carbon-to-oxygen ratio, slope and upper mass of top-heavy initial mass function, hard ionizing radiation and in-homogeneous dust distribution. Both CIII] and CIV line profiles are broadened with respect to the OIII] 1660 emission line. Each emission line of CIV 1548, 1550 shows the most distinct double-peak structure ever detected, which we model via two scenarios, firstly a double-peaked profile that might emerge from resonant scattering and secondly, a single nebular emission line along with a weaker interstellar absorption. The study demonstrates that galaxies with extreme FIR emission line ratio may also show extreme UV properties, hence paving a promising avenue of using FIR+UV in the local (via HST+Herschel/SOFIA) and distant (via JWST+ALMA) Universe for unveiling the mysteries of the EoR.

14.Connection Between SDSS Galaxies and ELUCID Subhaloes in the Eye of Machine Learning

Authors:Xiaoju Xu, Xiaohu Yang, Haojie Xu, Youcai Zhang

Abstract: We explore the feasibility of learning the connection between SDSS galaxies and ELUCID subhaloes with random forest (RF). ELUCID is a constrained $N$-body simulation constructed using the matter density field of SDSS. Based on an SDSS-ELUCID matched catalogue, we build RF models that predict $M_r$ magnitude, colour, stellar mass $M_*$, and specific star formation rate (sSFR) with several subhalo properties. While the RF can predict $M_r$ and $M_*$ with reasonable accuracy, the prediction accuracy of colour and sSFR is low, which could be due to the mismatch between galaxies and subhaloes. To test this, we shuffle the galaxies in subhaloes of narrow mass bins in the local neighbourhood using galaxies of a semi-analytic model (SAM) and the TNG hydrodynamic simulation. We find that the shuffling only slightly reduces the colour prediction accuracy in SAM and TNG, which is still considerably higher than that of the SDSS. This suggests that the true connection between SDSS colour and subhalo properties could be weaker than that in the SAM and TNG without the mismatch effect. We also measure the Pearson correlation coefficient between galaxy properties and the subhalo properties in SDSS, SAM, and TNG. Similar to the RF results, we find that the colour-subhalo correlation in SDSS is lower than both the SAM and TNG. We also show that the galaxy-subhalo correlations depend on subhalo mass in the galaxy formation models. Advanced surveys with more fainter galaxies will provide new insights into the galaxy-subhalo relation in the real Universe.

1.The Seoul National University AGN Monitoring Project IV: H$α$ reverberation mapping of 6 AGNs and the H$α$ Size-Luminosity Relation

Authors:Hojin Cho, Jong-Hak Woo, Shu Wang, Donghoon Son, Jaejin Shin, Suvendu Rakshit, Aaron J. Barth, Vardha N. Bennert, Elena Gallo, Edmund Hodges-Kluck, Tommaso Treu, Hyun-Jin Bae, Wanjin Cho, Adi Foord, Jaehyuk Geum, Yashashree Jadhav, Yiseul Jeon, Kyle M. Kabasares, Daeun Kang, Wonseok Kang, Changseok Kim, Donghwa Kim, Minjin Kim, Taewoo Kim, Huynh Anh N. Le, Matthew A. Malkan, Amit Kumar Mandal, Daeseong Park, Songyoun Park, Hyun-il Sung, Vivian U, Peter R. Williams

Abstract: The broad line region (BLR) size-luminosity relation has paramount importance for estimating the mass of black holes in active galactic nuclei (AGNs). Traditionally, the size of the H$\beta$ BLR is often estimated from the optical continuum luminosity at 5100\angstrom{} , while the size of the H$\alpha$ BLR and its correlation with the luminosity is much less constrained. As a part of the Seoul National University AGN Monitoring Project (SAMP) which provides six-year photometric and spectroscopic monitoring data, we present our measurements of the H$\alpha$ lags of 6 high-luminosity AGNs. Combined with the measurements for 42 AGNs from the literature, we derive the size-luminosity relations of H$\alpha$ BLR against broad H$\alpha$ and 5100\angstrom{} continuum luminosities. We find the slope of the relations to be $0.61\pm0.04$ and $0.59\pm0.04$, respectively, which are consistent with the \hb{} size-luminosity relation. Moreover, we find a linear relation between the 5100\angstrom{} continuum luminosity and the broad H$\alpha$ luminosity across 7 orders of magnitude. Using these results, we propose a new virial mass estimator based on the H$\alpha$ broad emission line, finding that the previous mass estimates based on the scaling relations in the literature are overestimated by up to 0.7 dex at masses lower than $10^7$~M$_{\odot}$.

2.A Dynamically Distinct Stellar Population in the Leading Arm of the Sagittarius Stream

Authors:Gwibong Kang, Young Sun Lee, Young Kwang Kim, Timothy C. Beers

Abstract: We present a chemical and dynamical analysis of the leading arm (LA) and trailing arm (TA) of the Sagittarius (Sgr) stream, as well as for the Sgr dwarf galaxy core (SC), using red giant branch, main sequence, and RR Lyrae stars from large spectroscopic survey data. The different chemical properties among the LA, TA, and SC generally agree with recent studies, and can be understood by radial metallicity gradient established in the progenitor of the Sgr dwarf, followed by preferential stellar stripping from the outer part of the Sgr progenitor. One striking finding is a relatively larger fraction of low-eccentricity stars (e < 0.4) in the LA than in the TA and SC. The TA and SC exhibit very similar distributions. Considering that a tidal tail stripped off from a dwarf galaxy maintains the orbital properties of its progenitor, we expect that the e-distribution of the LA should be similar to that of the TA and SC. Thus, the disparate behavior of the e-distribution of the LA is of particular interest. Following the analysis of Vasiliev et al., we attempt to explain the different e-distribution by introducing a time-dependent perturbation of the Milky Way by the Large Magellanic Cloud (LMC)'s gravitational pull, resulting in substantial evolution of the angular momentum of the LA stars to produce the low-e stars. In addition, we confirm from RR Lyrae stars with high eccentricity (e > 0.6) that the TA stars farther away from the SC are also affected by disturbances from the LMC.

3.Galaxies in voids assemble their stars slowly

Authors:J. Domínguez-Gómez, I. Pérez, T. Ruiz-Lara, R. F. Peletier, P. Sánchez-Blázquez, U. Lisenfeld, J. Falcón-Barroso, M. Alcázar-Laynez, M. Argudo-Fernández, G. Blázquez-Calero, H. Courtois, S. Duarte Puertas, D. Espada, E. Florido, R. García-Benito, A. Jiménez, K. Kreckel, M. Relaño, L. Sánchez-Menguiano, T. van der Hulst, R. van de Weygaert, S. Verley, A. Zurita

Abstract: Galaxies in the Universe are distributed in a web-like structure characterised by different large-scale environments: dense clusters, elongated filaments, sheetlike walls, and under-dense regions, called voids. The low density in voids is expected to affect the properties of their galaxies. Indeed, previous studies have shown that galaxies in voids are on average bluer and less massive, and have later morphologies and higher current star formation rates than galaxies in denser large-scale environments. However, it has never been observationally proved that the star formation histories (SFHs) in void galaxies are substantially different from those in filaments, walls, and clusters. Here we show that void galaxies have had, on average, slower SFHs than galaxies in denser large-scale environments. We also find two main SFH types present in all the environments: 'short-timescale' galaxies are not affected by their large-scale environment at early times but only later in their lives; 'long-timescale' galaxies have been continuously affected by their environment and stellar mass. Both types have evolved slower in voids than in filaments, walls, and clusters.

4.Gravitational collapse and accretion flows in the hub filament system G323.46-0.08

Authors:Yingxiu Ma, Jianjun Zhou, Jarken Esimbek, Willem Baan, Dalei Li, Xindi Tang, Yuxin He, Weiguang Ji, Dongdong Zhou, Gang Wu, Kadirya Tursun, Toktarkhan Komesh

Abstract: We studied the hub filament system G323.46-0.08 based on archival molecular line data from the SEDIGISM 13CO survey and infrared data from the GLIMPSE, MIPS, and Hi-GAL surveys. G323.46-0.08 consists of three filaments, F-north, F-west, and F-south, that converge toward the central high_mass clump AGAL 323.459-0.079. F-west and Part 1 of the F-south show clear large-scale velocity gradients 0.28 and 0.44 km s-1 pc-1, respectively. They seem to be channeling materials into AGAL 323.459-0.079. The minimum accretion rate was estimated to be 1216 M Myr-1. A characteristic V-shape appears around AGAL 323.459-0.079 in the PV diagram, which traces the accelerated gas motions under gravitational collapse. This has also been supported by model fitting results. All three filaments are supercritical and they have fragmented into many dense clumps. The seesaw patterns near most dense clumps in the PV diagram suggests that mass accretion also occurs along the filament toward the clumps. Our results show that filamentary accretion flows appear to be an important mechanism for supplying the materials necessary to form the central high-mass clump AGAL 323.459-0.079 and to propel the star forming activity taking place therein.

5.The History of The Milky Way: The Evolution of Star Formation, Cosmic Rays, Metallicity, and Stellar Dynamics over Cosmic Time

Authors:Jiro Shimoda, Shu-ichiro Inutsuka, Masahiro Nagashima

Abstract: We study the long-term evolution of the Milky Way (MW) over cosmic time by modeling the star formation, cosmic rays, metallicity, stellar dynamics, outflows and inflows of the galactic system to obtain various insights into the galactic evolution. The mass accretion is modeled by the results of cosmological $N$-body simulations for the cold dark matter. We find that the star formation rate is about half the mass accretion rate of the disk, given the consistency between observed Galactic Diffuse X-ray Emissions (GDXEs) and possible conditions driving the Galactic wind. Our model simultaneously reproduces the quantities of star formation rate, cosmic rays, metals, and the rotation curve of the current MW. The most important predictions of the model are that there is an unidentified accretion flow with a possible number density of $\sim10^{-2}$ cm$^{-3}$ and the part of the GDXEs originates from a hot, diffuse plasma which is formed by consuming about 10 % of supernova explosion energy. The latter is the science case for future X-ray missions; XRISM, Athena, and so on. We also discuss further implications of our results for the planet formation and observations of externalgalaxies in terms of the multimessenger astronomy.

6.An Overdensity of Lyman Break Galaxies Around the Hot Dust-Obscured Galaxy WISE J224607.56$-$052634.9

Authors:Dejene Zewdie UDP, Roberto J. Assef, Chiara Mazzucchelli, Manuel Aravena, Andrew W. Blain, Tanio Díaz-Santos, Peter R. M. Eisenhardt, Hyunsung D. Jun, Daniel Stern, Chao-Wei Tsai, "and" Jingwen W. Wu

Abstract: We report the identification of Lyman Break Galaxy (LBG) candidates around the most luminous Hot Dust-Obscured Galaxy (Hot DOG) known, WISE J224607.56$-$052634.9 (W2246$-$0526) at $z=4.601$, using deep \textit{r}-, \textit{i}-, and \textit{z}-band imaging from the Gemini Multi-Object Spectrograph South (GMOS-S). We use the surface density of LBGs to probe the Mpc-scale environment of W2246$-$0526 to characterize its richness and evolutionary state. We identify LBG candidates in the vicinity of W2246$-$0526 using the selection criteria developed by \cite{2004VOuchi} and \cite{2006Yoshida} in the Subaru Deep Field and in the Subaru XMM-Newton Deep Field, slightly modified to account for the difference between the filters used, and we find 37 and 55 LBG candidates, respectively. Matching to the $z$-band depths of those studies, this corresponds to $\delta = 5.8^{+2.4}_{-1.9}$ times the surface density of LBGs expected in the field. Interestingly, the Hot DOG itself, as well as a confirmed neighbor, do not satisfy either LBG selection criteria, suggesting we may be missing a large number of companion galaxies. Our analysis shows that we are most likely only finding those with higher-than-average IGM optical depth or moderately high dust obscuration. The number density of LBG candidates is not concentrated around W2246$-$0526, suggesting either an early evolutionary stage for the proto-cluster or that the Hot DOG may not be the most massive galaxy, or that the Hot DOG may be affecting the IGM transparency in its vicinity. The overdensity around W2246$-$0526 is comparable to overdensities found around other Hot DOGs and is somewhat higher than typically found for radio galaxies and luminous quasars at a similar redshift.

7.Fossil group origins XIII. A paradigm shift: fossil groups as isolated structures rather than relics of the ancient Universe

Authors:S. Zarattini, J. A. L. Aguerri, P. Tarrio, E. M. Corsini

Abstract: In this work we study the large-scale structure around a sample of non-fossil systems and compare the results with earlier findings for a sample of genuine fossil systems selected using their magnitude gap. We compute the distance from each system to the closest filament and intersection as obtained from a catalogue of galaxies in the redshift range $0.05 \le z \le 0.7$. We then estimate the average distances and distributions of cumulative distances to filaments and intersections for different bins of magnitude gap. We find that the average distance to filaments is $(3.0\pm 0.8)$ $R_{200}$ for fossil systems, whereas it is $(1.1\pm 0.1)\,R_{200}$ for non-fossil systems. Similarly, the average distance to intersections is larger in fossil than in non-fossil systems, with values of $(16.3\pm 3.2)$ and $(8.9\pm 1.1) \,R_{200}$, respectively. Moreover, the cumulative distributions of distances to intersections are statistically different between fossil and non-fossil systems. Fossil systems selected using the magnitude gap appear to be, on average, more isolated from the cosmic web than non-fossil systems. No dependence is found on the magnitude gap (i.e. non-fossil systems behave in a similar manner independently of their magnitude gap and only fossils are found at larger average distances from the cosmic web). This result supports a formation scenario for fossil systems in which the lack of infalling galaxies from the cosmic web, due to their peculiar position, favours the building of the magnitude gap via the merging of all the massive satellites with the central galaxy. Comparison with numerical simulations suggests that fossil systems selected using the magnitude gap are not old fossils of the ancient Universe, but systems located in regions of the cosmic web not influenced by the presence of intersections.

1.Inside MOND: Testing Gravity with Stellar Accelerations

Authors:Maxwell Finan-Jenkin University of Auckland, Richard Easther University of Auckland

Abstract: We quantify the differences between stellar accelerations in disk galaxies formed in a MONDian universe relative to galaxies with the identical baryonic matter distributions and a fitted cold dark matter halo. In a Milky Way-like galaxy the maximal transverse acceleration is ${\cal {O}}(10^{-9})$ arcseconds per year per decade, well beyond even the most optimistic extrapolations of current capabilities. Conversely, the maximum difference in the line-of-sight acceleration is ${\cal {O}}(1)$ centimetre per second per decade at solar distances from the galactic centre. This level of precision is within reach of plausible future instruments.

2.The Centimeter to Submillimeter Broad Band Radio Spectrum of the Central Compact Component in A Nearby Type-II Seyfert Galaxy NGC 1068

Authors:Tomonari Michiyama, Yoshiyuki Inoue, Akihiro Doi

Abstract: We analyze all the available Atacama Large Millimeter / submillimeter Array archival data of the nearby Type-II Seyfert galaxy NGC 1068, including new 100 GHz data with the angular resolution of 0\farcs05, which was not included in previous continuum spectral analysis. By combining with the literature data based on the Very Large Array, we investigate the broadband radio continuum spectrum of the central $\lesssim7$ pc region of NGC 1068. We found that the flux density is between $\approx$10-20 mJy at 5-700 GHz. Due to the inability of the model in previous studies to account for the newly added 100 GHz data point, we proceeded to update the models and make the necessary adjustments to the parameters. One possible interpretation of this broadband radio spectrum is a combination of emission from the jet base, the dusty torus, and the compact X-raying corona with the magnetic field strength of $\approx20$ G on scales of $\approx30$ Schwarzschild radii from the central black hole. In order to firmly identify the compact corona by omitting any other possible extended components (e.g., free-free emission from ionized gas around), high-resolution/sensitivity observations achieved by next-generation interferometers will be necessary.

3.Cosmic-ray-driven enhancement of the C$^0$/CO abundance ratio in W51C

Authors:Mitsuyoshi Yamagishi, Kenji Furuya, Hidetoshi Sano, Natsuko Izumi, Tatsuya Takekoshi, Hidehiro Kaneda, Kouichiro Nakanishi, Takashi Shimonishi

Abstract: We examine spatial variations of the C$^0$/CO abundance ratio ($X_{\mathrm{C/CO}}$) in the vicinity of the $\gamma$-ray supernova remnant W51C, based on [CI] ($^3P_1$-$^3P_0$), $^{12}$CO(1-0), and $^{13}$CO(1-0) observations with the ASTE and Nobeyama 45-m telescopes. We find that $X_{\mathrm{C/CO}}$ varies in a range of 0.02-0.16 (0.05 in median) inside the molecular clouds of $A_V>$100 mag, where photodissociation of CO by the interstellar UV is negligible. Furthermore, $X_{\mathrm{C/CO}}$ is locally enhanced up to by a factor of four near the W51C center, depending on the projected distance from the W51C center. In high-$A_V$ molecular clouds, $X_{\mathrm{C/CO}}$ is determined by the ratio of the cosmic-ray (CR) ionization rate to the H$_2$ density, and we find no clear spatial variation of the H$_2$ density against the projected distance. Hence, the high CR ionization rate may locally enhance $X_{\mathrm{C/CO}}$ near the W51C center. We also find that the observed spatial extent of the enhanced $X_{\mathrm{C/CO}}$ ($\sim$17 pc) is consistent with the diffusion distance of CRs with the energy of 100 MeV. The fact suggests that the low-energy CRs accelerated in W51C enhance $X_{\mathrm{C/CO}}$. The CR ionization rate at the $X_{\mathrm{C/CO}}$-enhanced cloud is estimated to be 3$\times$10$^{-16}$ s$^{-1}$ on the basis of time-dependent PDR simulations of $X_{\mathrm{C/CO}}$, the value of which is 30 times higher than that in the standard Galactic environment. These results demonstrate that [CI] is a powerful probe to investigate the interaction between CRs and the interstellar medium for a wide area in the vicinity of supernova remnants.

4.Hidden giants in JWST's PEARLS: An ultra-massive z=4.26 sub-millimeter galaxy that is invisible to HST

Authors:Ian Smail, Ugne Dudzeviciute, Mark Gurwell, Giovanni G. Fazio, S. P. Willner, A. M. Swinbank, Vinodiran Arumugam, Jake Summers, Seth H. Cohen, Rolf A. Jansen, Rogier A. Windhorst, Ashish Meena, Adi Zitrin, William C. Keel, Dan Coe, Christopher J. Conselice, Jordan C. J. D'Silva, Simon P. Driver, Brenda Frye, Norman A. Grogin, Anton M. Koekemoer, Madeline A. Marshall, Mario Nonino, Nor Pirzkal, Aaron Robotham, Michael J. Rutkowski, Russell E. Ryan Jr., Scott Tompkins, Christopher N. A. Willmer, Haojing Yan, Thomas J. Broadhurst, Cheng Cheng, Jose M. Diego, Patrick Kamieneski, Min Yun

Abstract: We present a multi-wavelength analysis using SMA, JCMT, NOEMA, JWST, HST, and SST of two dusty strongly star-forming galaxies, 850.1 and 850.2, seen through the massive cluster lens A1489. These SMA-located sources both lie at z=4.26 and have bright dust continuum emission, but 850.2 is a UV-detected Lyman-break galaxy, while 850.1 is undetected at <2um, even with deep JWST/NIRCam observations. We investigate their stellar, ISM, and dynamical properties, including a pixel-level SED analysis to derive sub-kpc-resolution stellar-mass and Av maps. We find that 850.1 is one of the most massive and highly obscured, Av~5, galaxies known at z>4 with M*~10^11.8 Mo (likely forming at z>6), and 850.2 is one of the least massive and least obscured, Av~1, members of the z>4 dusty star-forming population. The diversity of these two dust-mass-selected galaxies illustrates the incompleteness of galaxy surveys at z>3-4 based on imaging at <2um, the longest wavelengths feasible from HST or the ground. The resolved mass map of 850.1 shows a compact stellar mass distribution, Re(mass)~1kpc, but its expected evolution to z~1.5 and then z~0 matches both the properties of massive, quiescent galaxies at z~1.5 and ultra-massive early-type galaxies at z~0. We suggest that 850.1 is the central galaxy of a group in which 850.2 is a satellite that will likely merge in the near future. The stellar morphology of 850.1 shows arms and a linear bar feature which we link to the active dynamical environment it resides within.

5.GAMA/DEVILS: Cosmic star formation and AGN activity over 12.5 billion years

Authors:Jordan C. J. D'Silva, Simon P. Driver, Claudia D. P. Lagos, Aaron S. G. Robotham, Sabine Bellstedt, Luke J. M. Davies, Jessica E. Thorne, Joss Bland-Hawthorn, Matias Bravo, Benne Holwerda, Steven Phillipps, Nick Seymour, Malgorzata Siudek, Rogier A. Windhorst

Abstract: We use the Galaxy and Mass Assembly (GAMA) and the Deep Extragalactic Visible Legacy Survey (DEVILS) observational data sets to calculate the cosmic star formation rate (SFR) and active galactic nuclei (AGN) bolometric luminosity history (CSFH/CAGNH) over the last 12.5 billion years. SFRs and AGN bolometric luminosities were derived using the spectral energy distribution fitting code ProSpect, which includes an AGN prescription to self consistently model the contribution from both AGN and stellar emission to the observed rest-frame ultra-violet to far-infrared photometry. We find that both the CSFH and CAGNH evolve similarly, rising in the early Universe up to a peak at look-back time $\approx 10$~Gyr ($z \approx 2$), before declining toward the present day. The key result of this work is that we find the ratio of CAGNH to CSFH has been flat ($\approx 10^{42.5}\mathrm{erg \, s^{-1}M_{\odot}^{-1}yr}$) for $11$~Gyr up to the present day, indicating that star formation and AGN activity have been coeval over this time period. We find that the stellar masses of the galaxies that contribute most to the CSFH and CAGNH are similar, implying a common cause, which is likely gas inflow. The depletion of the gas supply suppresses cosmic star formation and AGN activity equivalently to ensure that they have experienced similar declines over the last 10 Gyr. These results are an important milestone for reconciling the role of star formation and AGN activity in the life cycle of galaxies.

6.The LOFAR view of massive early-type galaxies: Transition from radio AGN to host emission

Authors:A. Capetti INAF - Osservatorio Astrofisico di Torino, Strada Osservatorio 20, I-10025 Pino Torinese, Italy, M. Brienza INAF - Istituto di Radio Astronomia, Via P. Gobetti 101, I-40129 Bologna, Italy Dipartimento di Fisica e Astronomia, Università di Bologna, Via P. Gobetti 93/2, I-40129, Bologna, Italy

Abstract: We extend the study of the radio emission in early-type galaxies (ETGs) in the nearby Universe (recession velocity <7,500 km/s) as seen by the 150 MHz Low-Frequency ARray (LOFAR) observations and extend the sample from giant ETGs to massive (~6x10^10 - 3x10^11 solar masses) ETGs (mETGS) with -25 < MK < -23.5. Images from the second data release of the LOFAR Two-metre Sky Survey were available for 432 mETGs, 48% of which are detected above a typical luminosity of ~3x10^20 W/Hz. Most (85%) of the detected sources are compact, with sizes <4 kpc. The radio emission of 31 mETGs is extended on scales ranging from 2 to 180 kpc (median 12 kpc). In several cases, it is aligned with the host galaxy. We set a limit of ~1% to the fraction of remnant or restarted objects, which is ~16% of the extended sources. We found that the properties of the radio sources are connected with the stellar mass of the ETGs (the median radio power, the fraction of extended radio sources, and the link with the large-scale environment). However, these results only describe statistical trends because the radio properties of sources of similar stellar mass and environment show a large spread of radio properties. These trends break at the lowest host luminosities (MK>-24.5). This effect is strengthened by the analysis of even less massive ETGs, with -23.5 < MK < -21.5. This suggests that at a mass of ~2x10^11 solar masses, a general transition occurs from radio emission produced from radio-loud active galactic nuclei (AGN) to processes related to the host galaxy and (or) radio quiet AGN. At this luminosity, a transition in the stellar surface brightness profile also occurs from Sersic galaxies to those with a depleted stellar core, the so-called core galaxies. This finding is in line with previous results that indicated that only core galaxies host radio-loud AGN.

1.Episodic Accretion in Protostars -- An ALMA Survey of Molecular Jets in the Orion Molecular Cloud

Authors:Somnath Dutta, Chin-Fei Lee, Doug Johnstone, Jeong-Eun Lee, Naomi Hirano, James Di Francesco, Anthony Moraghan, Tie Liu, Dipen Sahu, Sheng-Yuan Liu, Kenichi Tatematsu, Chang Won Lee, Shanghuo Li, David Eden, Mika Juvela, Leonardo Bronfman, Shih-Ying Hsu, Kee-Tae Kim, Woojin Kwon, Patricio Sanhueza, Jesus Alejandro Lopez-Vazquez, Qiuyi Luo, Hee-Weon Yi

Abstract: Protostellar outflows and jets are almost ubiquitous characteristics during the mass accretion phase, and encode the history of stellar accretion, complex-organic molecule (COM) formation, and planet formation. Episodic jets are likely connected to episodic accretion through the disk. Despite the importance, there is a lack of studies of a statistically significant sample of protostars via high-sensitivity and high-resolution observations. To explore episodic accretion mechanisms and the chronologies of episodic events, we investigated 42 fields containing protostars with ALMA observations of CO, SiO, and 1.3\,mm continuum emission. We detected SiO emission in 21 fields, where 19 sources are driving confirmed molecular jets with high abundances of SiO. Jet velocities, mass-loss rates, mass-accretion rates, and periods of accretion events are found to be dependent on the driving forces of the jet (e.g., bolometric luminosity, envelope mass). Next, velocities and mass-loss rates are positively correlated with the surrounding envelope mass, suggesting that the presence of high mass around protostars increases the ejection-accretion activity. We determine mean periods of ejection events of 20$-$175 years for our sample, which could be associated with perturbation zones of $\sim$ 2$-$25\,au extent around the protostars. Also, mean ejection periods are anti-correlated with the envelope mass, where high-accretion rates may trigger more frequent ejection events. The observed periods of outburst/ejection are much shorter than the freeze-out time scale of the simplest COMs like CH$_3$OH, suggesting that episodic events largely maintain the ice-gas balance inside and around the snowline.

2.Astrophysical Parameters of the Open Cluster Berkeley 6

Authors:S. Koc, T. Yontan

Abstract: In this study, the structural and basic astrophysical parameters of the poorly studied open cluster Berkeley 6 are calculated. Analyses of the cluster are carried out using the third photometric, spectroscopic, and astrometric data release of Gaia (Gaia DR3). The membership probabilities of stars located in the direction of the cluster region are calculated by considering their astrometric data. Thus, we identified 119 physical members for Berkeley 6. The colour excess, distance, and age of the cluster are determined simultaneously on the colour-magnitude diagram. We fitted solar metallicity PARSEC isochrones to the colour-magnitude diagram by considering the most probable member stars and obtained $E(G_{\rm BP}-G_{\rm RP})$ colour excess as 0.918$\pm$0.145 mag. The distance and age of the cluster are determined as $d=2625\pm337$ pc and $t=350\pm50$ Myr, respectively.

3.An ongoing tidal capture in the Large Magellanic Cloud: the low-mass star cluster KMK88-10 captured by the massive globular cluster NGC 1835?

Authors:Camilla Giusti, Mario Cadelano, Francesco R. Ferraro, Barbara Lanzoni, Silvia Leanza, Cristina Pallanca, Enrico Vesperini, Emanuele Dalessandro, Alessio Mucciarelli

Abstract: In the context of a project aimed at characterizing the dynamical evolution of old globular clusters in the Large Magellanic Cloud, we have secured deep HST/WFC3 images of the massive cluster NGC 1835. In the field of view of the acquired images, at a projected angular separation of approximately 2 arcmin from the cluster, we detected the small stellar system KMK88-10. The observations provided the deepest color-magnitude diagram ever obtained for this cluster, revealing that it hosts a young stellar population with an age of 600-1000 Myr. The cluster surface brightness profile is nicely reproduced by a King model with a core radius rc = 4 arcsec (0.97 pc), an half-mass radius rhm = 12 arcsec (2.9 pc), and a concentration parameter c~1.3 corresponding to a truncation radius rt~81 arcsec (19.5 pc). We also derived its integrated absolute magnitude (MV=-0.71) and total mass (M~80-160 Msun). The most intriguing feature emerging from this analysis is that KMK88-10 presents a structure elongated in the direction of NGC 1835, with an intracluster over-density that suggests the presence of a tidal bridge between the two systems. If confirmed, this would be the first evidence of a tidal capture of a small star cluster by a massive globular.

4.On the Hα faintness of the North Polar Spur

Authors:Yoshiaki Sofue, Jun Kataoka, Ryoji Iwashita

Abstract: The ratio of the H$\alpha$ and radio continuum intensities in the North Polar Spur (NPS) is measured to be $\lesssim 50$, two orders of magnitude smaller than the values observed in the typical shell-type old supernova remnants (SNRs), Cygnus Loop and S147, of $\sim 10^4$.The extremely low} H$\alpha$-to-radio intensity ratio favors the GC explosion model}, which postulates a giant shock wave in the hot and low-density Galactic halo with low hydrogen recombination rate, over the local supernova(e) remnant model.

5.Discovery and Characterization of Galactic-scale Dual Supermassive Black Holes Across Cosmic Time

Authors:Yue Shen, J. Andrew Casey-Clyde, Yu-Ching Chen, Arran Gross, Melanie Habouzit, Hsiang-Chih Hwang, Yuzo Ishikawa, Jun-Yao Li, Xin Liu, Chiara M. F. Mingarelli, D. Porquet, Aaron Stemo, Ming-Yang Zhuang

Abstract: The hierarchical structure formation paradigm predicts the formation of pairs of supermassive black holes in merging galaxies. When both (or one) members of the SMBH pair are unobscured AGNs, the system can be identified as a dual (or offset) AGN. Quantifying the abundance of these AGN pairs as functions of separation, redshift and host properties is crucial to understanding SMBH formation and AGN fueling in the broad context of galaxy formation. The High Latitude Wide Area Survey with Roman, with its unprecedented combination of sensitivity, spatial resolution, area and NIR wavelength coverage, will revolutionize the study of galactic-scale environments of SMBH pairs. This white paper summarizes the science opportunities and technical requirements on the discovery and characterization of SMBH pairs down to galactic scales (i.e., less than tens of kpc) over broad ranges of redshift (1<z<7) and luminosity (Lbol>1E42 erg/s).

6.The Stellar Abundances and Galactic Evolution Survey (SAGES) -- -- I. General Description and the First Data Release (DR1)

Authors:Zhou Fan, Gang Zhao, Wei Wang, Jie Zheng, Jingkun Zhao, Chun Li, Yuqin Chen, Haibo Yuan, Haining Li, Kefeng Tan, Yihan Song, Fang Zuo, Yang Huang, Ali Luo, Ali Esamdin, Lu Ma, Bin Li, Nan Song, Frank Grupp, Haibin Zhao, Shuhrat A. Ehgamberdiev, Otabek A. Burkhonov, Guojie Feng, Chunhai Bai, Xuan Zhang, Hubiao Niu, Alisher S. Khodjaev, Bakhodir M. Khafizov, Ildar M. Asfandiyarov, Asadulla M. Shaymanov, Rivkat G. Karimov, Qudratillo Yuldashev, Hao Lu, Getu Zhaori, Renquan Hong, Longfei Hu, Yujuan Liu, Zhijian Xu

Abstract: The Stellar Abundances and Galactic Evolution Survey (SAGES) of the northern sky is a specifically-designed multi-band photometric survey aiming to provide reliable stellar parameters with accuracy comparable to those from low-resolution optical spectra. It was carried out with the 2.3-m Bok telescope of Steward Observatory and three other telescopes. The observations in the $u_s$ and $v_s$ passband produced over 36,092 frames of images in total, covering a sky area of $\sim9960$ degree$^2$. The median survey completeness of all observing fields for the two bands are of $u_{\rm s}=20.4$ mag and $v_s=20.3$ mag, respectively, while the limiting magnitudes with signal-to-noise ratio (S/N) of 100 are $u_s\sim17$ mag and $v_s\sim18$ mag, correspondingly. We combined our catalog with the data release 1 (DR1) of the first of Panoramic Survey Telescope And Rapid Response System (Pan-STARRS1, PS1) catalog, and obtained a total of 48,553,987 sources which have at least one photometric measurement in each of the SAGES $u_s$ and $v_s$ and PS1 $grizy$ passbands, which is the DR1 of SAGES and it will be released in our paper. We compare our $gri$ point-source photometry with those of PS1 and found an RMS scatter of $\sim2$% in difference of PS1 and SAGES for the same band. We estimated an internal photometric precision of SAGES to be on the order of $\sim1$%. Astrometric precision is better than $0^{\prime\prime}.2$ based on comparison with the DR1 of Gaia mission. In this paper, we also describe the final end-user database, and provide some science applications.

1.Rejuvenating Star Formation Activity in an Early-type Dwarf Galaxy, LEDA 1915372, with Accreted HI Gas

Authors:Sanjaya Paudel, Suk-Jin Yoon, Omkar Bait, Chandreyee Sengupta, Woong-Bae G. Zee, Daya Nidhi Chhatkuli, Binod Adhikari, Binil Aryal

Abstract: We report a rare astrophysical phenomenon, in which an early-type dwarf galaxy (dE), LEDA 1915372, is accreting gas from a nearby star-forming dwarf galaxy, MRK 0689, and is rejuvenating star-formation activity at the center. Both LEDA 1915372 and MRK 0689 have similar brightness of $M_{r}$ = $-$16.99 and $-$16.78 mag, respectively. They are located in a small group environment, separated by a sky-projected distance of 20.27 kpc (up to 70 kpc in three dimension), and have a relative line-of-sight radial velocity of 6 km/s. The observation of 21 cm emission with the Giant Metrewave Radio Telescope provides strong evidence of interaction between the pair dwarf galaxies in terms of neutral hydrogen (HI) morphology and kinematics. In particular, the HI map reveals that the two galaxies are clearly connected by a gas bridge, and the gas components of both LEDA 1915372 and MRK 0689 share a common direction of rotation. We also find that the HI emission peak deviates from LEDA 1915372 toward its optical blue plume, suggesting a tidal origin of ongoing central star formation. Our findings provide a new path to the formation of blue-cored dEs.

2.Episodic infall towards a compact disk in B335?

Authors:Per Bjerkeli, Jon P. Ramsey, Daniel Harsono, Adele Plunkett, Zhi-Yun Li, Matthijs H. D., van der Wiel, Hannah Calcutt, Jes K. Jørgensen, Lars E. Kristensen

Abstract: Previous observations of B335 have presented evidence of ongoing infall in various molecular lines, e.g., HCO$^+$, HCN, CO. There have been no confirmed observations of a rotationally supported disk on scales greater than ~12~au. The presence of an outflow in B335 suggests that also a disk should be present or in formation. To constrain the earliest stages of protostellar evolution and disk formation, we aim to map the region where gas falls inwards and observationally constrain its kinematics. Furthermore, we aim to put strong limits on the size and orientation of any disk-like structure in B335. We use high angular resolution $^{13}$CO data from ALMA, and combine it with shorter-baseline archival data to produce a high-fidelity image of the infall in B335. We also revisit the imaging of high-angular resolution Band 6 continuum data to study the dust distribution in the immediate vicinity of B335. Continuum emission shows an elliptical structure (10 by 7 au) with a position angle 5 degrees east of north, consistent with the expectation for a forming disk in B335. A map of the infall velocity (as estimated from the $^{13}$CO emission), shows evidence of asymmetric infall, predominantly from the north and south. Close to the protostar, infall velocities appear to exceed free-fall velocities. 3D radiative transfer models, where the infall velocity is allowed to vary within the infall region, can explain the observed kinematics. The data suggests that a disk has started to form in B335 and that gas is falling towards that disk. However, kinematically-resolved line data towards the disk itself is needed to confirm the presence of a rotationally supported disk around this young protostar. The measured high infall velocities are not easily reconcilable with a magnetic braking scenario and suggest that there is a pressure gradient that allows the infall velocity to vary in the region.

3.Hydrodynamic simulations of the Disk of Gas Around Supermassive black holes (HDGAS) -I; Molecular Gas Dynamics

Authors:Mojtaba Raouf, Serena Viti, S. García-Burillo, Alexander J. Richings, Joop schaye, Ashley Bemis, Folkert S. J. Nobels, Matteo Guainazzi, Ko-Yun Huang, Matthieu Schaller, Violette Impellizzeri, Jon Holdship

Abstract: We present hydrodynamic simulations of the interstellar medium (ISM) within the circumnuclear disk (CND) of a typical AGN-dominated galaxy influenced by mechanical feedback from an active galactic nucleus(AGN). The simulations are coupled with the CHIMES non-equilibrium chemistry network to treat the radiative-cooling and AGN-heating. A focus is placed on the central 100 pc scale where AGN outflows are coupled to the ISM and constrained by observational Seyfert-2 galaxies. AGN-feedback models are implemented with different wind-velocity and mass-loading factors. We post-process the simulation snapshots with a radiative-transfer code to obtain the molecular emission lines. We find that the inclusion of an AGN promotes the formation of CO in clumpy and dense regions surrounding supermassive-blackholes (SMBH). The CO(1-0) intensity maps ($<$6 Myr) in the CND seem to match well with observations of NGC 1068 with a best match for a model with 5000 $\rm km/s$ wind-velocity and a high mass-loading factor. We attempt to discern between competing explanations for the apparent counter-rotating gas disk in the NGC 1068 through an analysis of kinematic maps of the CO line emission. We suggest that mechanical AGN-feedback could explain the alignment-stability of position-angle across the different CND radii around the SMBH through momentum and energy loading of the wind. It is the wind-velocity that drives the disk out of alignment on a 100 pc scale for a long period of time. The position-velocity diagrams are in broad agreement with the predicted Keplerian rotation-curve in the model without-AGN, but the AGN models exhibit a larger degree of scatter, in better agreement with NGC 1068 observations.

4.ALMA-IMF VII -- First release of the full spectral line cubes:Core kinematics traced by DCN J=(3-2)

Authors:N. Cunningham, A. Ginsburg, R. Galván-Madrid, F. Motte, T. Csengeri, A. M. Stutz, M. Fernández-López, R. H. Álvarez-Gutiérrez, M. Armante, T. Baug, M. Bonfand, S. Bontemps, J. Braine, N. Brouillet, G. Busquet, D. J. Díaz-González, J. Di Francesco, A. Gusdorf, F. Herpin, H. Liu, A. López-Sepulcre, F. Louvet, X. Lu, L. Maud, T. Nony, F. A. Olguin, Y. Pouteau, R. Rivera-Soto, N. A. Sandoval-Garrido, P. Sanhueza, K. Tatematsu, A. P. M. Towner, M. Valeille-Manet

Abstract: ALMA-IMF is an Atacama Large Millimeter/submillimeter Array (ALMA) Large Program designed to measure the core mass function (CMF) of 15 protoclusters chosen to span their early evolutionary stages. It further aims to understand their kinematics, chemistry, and the impact of gas inflow, accretion, and dynamics on the CMF. We present here the first release of the ALMA-IMF line data cubes (DR1), produced from the combination of two ALMA 12m-array configurations. The data include 12 spectral windows, with eight at 1.3mm and four at 3mm. The broad spectral coverage of ALMA-IMF (~6.7 GHz bandwidth coverage per field) hosts a wealth of simple atomic, molecular, ionised, and complex organic molecular lines. We describe the line cube calibration done by ALMA and the subsequent calibration and imaging we performed. We discuss our choice of calibration parameters and optimisation of the cleaning parameters, and we demonstrate the utility and necessity of additional processing compared to the ALMA archive pipeline. As a demonstration of the scientific potential of these data, we present a first analysis of the DCN (3-2) line. We find that DCN traces a diversity of morphologies and complex velocity structures, which tend to be more filamentary and widespread in evolved regions and are more compact in the young and intermediate-stage protoclusters. Furthermore, we used the DCN (3-2) emission as a tracer of the gas associated with 595 continuum cores across the 15 protoclusters, providing the first estimates of the core systemic velocities and linewidths within the sample. We find that DCN (3-2) is detected towards a higher percentage of cores in evolved regions than the young and intermediate-stage protoclusters and is likely a more complete tracer of the core population in more evolved protoclusters. The full ALMA 12m-array cubes for the ALMA-IMF Large Program are provided with this DR1 release.

5.The temporal evolution of gas accretion onto the discs of simulated Milky Way-mass galaxies

Authors:F. G. Iza Instituto de Astronomía y Física del Espacio Departamento de Física, Universidad de Buenos Aires Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina, S. E. Nuza Instituto de Astronomía y Física del Espacio Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina, C. Scannapieco Departamento de Física, Universidad de Buenos Aires Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina

Abstract: In the standard model of structure formation, galaxies form in the centre of dark matter haloes that develop as a result of inhomogeneities in the primordial mass distribution of the Universe. Afterwards, galaxies grow by means of continuous accretion of gaseous material stemming from the intergalactic medium, both in diffuse form and through collisions with other systems. After an initial period of violent growth, the gas settles into a rotationally-supported structure where stars are born, giving birth to the stellar disc. The accretion of gaseous material onto the disc plays a fundamental role in its evolution as it can change its dynamical and morphological properties, generating gas flows within the disc. In this work, we use 30 galaxies from the Auriga Project, a set of cosmological magnetohydrodynamical simulations of disc galaxies, to study the temporal dependence of the gas accretion rates, focusing on the inflowing and outflowing fluxes.

6.Merger-driven infall of metal-poor gas in luminous infrared galaxies: a deep dive beneath the mass-metallicity relation

Authors:Borja Pérez-Díaz, Enrique Pérez-Montero, Juan A. Fernández-Ontiveros, José M. Vílchez, Ricardo Amorín

Abstract: The build up of heavy elements and the stellar mass assembly are fundamental processes in the formation and evolution of galaxies. Although they have been extensively studied through observations and simulations, the key elements that govern these processes, such as gas accretion and outflows, are not fully understood. This is especially true for luminous and massive galaxies, which usually suffer strong feedback in the form of massive outflows, and large-scale gas accretion triggered by galaxy interactions. For a sample of 77 luminous infrared (IR) galaxies, we derive chemical abundances using new diagnostics based on nebular IR lines, which peer through the dusty medium of these objects and allow us to include the obscured metals in our abundance determinations. In contrast to optical-based studies, our analysis reveals that most luminous IR galaxies remain close to the mass-metallicity relation. Nevertheless, four galaxies with extreme star-formation rates ($> 60$M$_{\odot }$yr$^{-1}$) in their late merger stages show heavily depressed metallicities of 12+log(O/H) $\sim 7.7$--$8.1$ along with solar-like N/O ratios, indicative of gas mixing processes affecting their chemical composition. This evidence suggests the action of a massive infall of metal-poor gas in a short phase during the late merger stages, eventually followed by a rapid enrichment. These results challenge the classical gas equilibrium scenario usually applied to main-sequence galaxies, suggesting that the chemical enrichment and stellar-mass growth in luminous IR galaxies are regulated by different processes.

7.Molecular gas distribution and CO-to-H2 conversion factors in CO-faint low-metallicity dwarf galaxies

Authors:L. Ramambason, V. Lebouteiller, S. C. Madden, F. Galliano, C. T. Richardson, A. Saintonge, I. De Looze, M. Chevance, N. P. Abel, S. Hernandez, J. Braine

Abstract: Low-metallicity dwarf galaxies often show no or little CO emission, despite the intense star formation observed in local samples. Both simulations and resolved observations indicate that molecular gas in low-metallicity galaxies may reside in small dense clumps, surrounded by a substantial amount of more diffuse gas, not traced by CO. Constraining the relative importance of CO-bright versus CO-dark H2 star-forming reservoirs is crucial to understand how star formation proceeds at low metallicity. We put to the test classically used single component radiative transfer models and compare their results to those obtained assuming an increasingly complex structure of the interstellar gas, mimicking an inhomogeneous distribution of clouds with various physical properties. We compute representative models of the interstellar medium as combinations of several gas components, each with a specific set of physical parameters. We introduce physically-motivated models assuming power-law distributions for the density, ionization parameter, and the depth of molecular clouds. We confirm the presence of a predominantly CO-dark molecular reservoir in low-metallicity galaxies. The predicted total H2 mass is best traced by [C II]158um and, to a lesser extent, by [CI] 609um, rather than by CO(1-0). We examine the CO-to-H2 conversion factor vs. metallicity relation and find that its dispersion increases significantly when different geometries of the gas are considered. We define a clumpiness parameter that anti-correlates with [CII]/CO and explains the dispersion of the CO-to-H2 conversion factor vs. metallicity relation. We find that low-metallicity galaxies with high clumpiness may have CO-to-H2 conversion factor as low as the Galactic value. We identify the clumpiness of molecular gas as a key parameter to understand variations of geometry-sensitive quantities, such as CO-to-H2 conversion factor.

1.The probability of identifying the cosmic web environment of galaxies around clusters motivated by the Weave Wide Field Cluster Survey

Authors:Daniel J. Cornwell, Alfonso Aragón-Salamanca, Ulrike Kuchner, Meghan E. Gray, Frazer R. Pearce, Alexander Knebe

Abstract: Upcoming wide-field spectroscopic surveys will observe galaxies in a range of cosmic web environments in and around galaxy clusters. In this paper, we test and quantify how successfully we will be able to identify the environment of individual galaxies in the vicinity of massive galaxy clusters, reaching out to $\sim5R_{200}$ into the clusters' infall region. We focus on the WEAVE Wide Field Cluster Survey (WWFCS), but the methods we develop can be easily generalised to any similar spectroscopic survey. Using numerical simulations of a large sample of massive galaxy clusters from \textsc{TheThreeHundred} project, we produce mock observations that take into account the selection effects and observational constraints imposed by the WWFCS. We then compare the `true' environment of each galaxy derived from the simulations (cluster core, filament, and neither core nor filament, {``NCF''}) with the one derived from the observational data, where only galaxy sky positions and spectroscopic redshifts will be available. We find that, while cluster core galaxy samples can be built with a high level of completeness and moderate contamination, the filament and NCF galaxy samples will be significantly contaminated and incomplete due to projection effects exacerbated by the galaxies' peculiar velocities. We conclude that, in the infall regions surrounding massive galaxy clusters, associating galaxies with the correct cosmic web environment is highly uncertain. However, with large enough spectroscopic samples like the ones the WWFCS will provide (thousands of galaxies per cluster, {out to $5R_{200}$}), and the correct statistical treatment that takes into account the probabilities we provide here, we expect we will be able to extract robust and well-quantified conclusions on the relationship between galaxy properties and their environment.

2.The GUAPOS project:III. Characterization of the O- and N-bearing complex organic molecules content and search for chemical differentiation

Authors:C. Mininni, M. T. Beltrán, L. Colzi, V. M. Rivilla, F. Fontani, A. Lorenzani, Á. López-Gallifa, S. Viti, Á. Sánchez-Monge, P. Schilke, L. Testi

Abstract: The G31.41+0.31 Unbiased ALMA sPectral Observational Survey (GUAPOS) project targets the hot molecular core (HMC) G31.41+0.31 (G31), to unveil the complex chemistry of one of the most chemically rich high-mass star-forming regions outside the Galactic Center (GC). In the third paper of the project, we present a study of nine O-bearing (CH$_3$OH, $^{13}$CH$_3$OH, CH$_3^{18}$OH, CH$_3$CHO, CH$_3$OCH$_3$, CH$_3$COCH$_3$ , C$_2$H$_5$OH, aGg'-(CH$_2$OH)$_2$, and gGg'-(CH$_2$OH)$_2$) and six N-bearing (CH$_3$CN, $^{13}$CH$_3$CN, CH$_3^{13}$CN, C$_2$H$_3$CN, C$_2$H$_5$CN, and C$_2$H$_5^{13}$CN) complex organic molecules toward G31. The aim of this work is to characterize the abundances in one of the most chemically-rich hot molecular cores outside the GC and to search for a possible chemical segregation between O-bearing and N-bearing species in G31, which hosts four compact sources as seen with higher angular resolution data. Observations were carried out with the interferometer ALMA and covered the entire Band 3 from 84 to 116 GHz ($\sim 32$ GHz bandwidth) with an angular resolution of $1.2''$ ($\sim4400\,\mathrm{au}$). The spectrum has been analyzed with the tool SLIM of MADCUBA to determine the physical parameters of the emitting gas. Moreover, we have analyzed the morphology of the emission of the molecular species. We have compared the abundances w.r.t methanol of COMs in G31 with other twenty-seven sources, including other hot molecular cores inside and outside the Galactic Center, hot corinos, shocked regions, envelopes around young stellar objects, and quiescent molecular clouds, and with chemical models. Different species peak at slightly different positions, and this, together with the different central velocities of the lines obtained from the spectral fitting, point to chemical differentiation of selected O-bearing species.

3.X-ray Analysis of AGN from the GALEX Time Domain Survey

Authors:Erik J. Wasleske, Vivienne F. Baldassare

Abstract: We analyze the X-ray properties for a sample of 23 high probability AGN candidates with ultraviolet variability identified in Wasleske et al. (2022). Using data from the Chandra X-ray Observatory and the XMM-Newton Observatory, we find 11/23 nuclei are X-ray detected. We use SED modeling to compute star formation rates and show that the X-ray luminosities are typically in excess of the X-ray emission expected from star formation by at least an order of magnitude. Interestingly, this sample shows a diversity of optical spectroscopic properties. We explore possible reasons for why some objects lack optical spectroscopic signatures of black hole activity while still being UV variable and X-ray bright. We find that host galaxy stellar emission and obscuration from gas and dust are all potential factors. We study where this sample falls on relationships such as $\alpha_{\rm OX}-L_{2500}$ and $L_{X}-L_{IR}$ and find that some of the sample falls outside the typical scatter for these relations, indicating they differ from the standard quasar population. With the diversity of optical spectroscopic signatures and varying impacts of dust and stellar emissions on our sample, these results emphasizes the strength of variability in selecting the most complete set of AGN, regardless of other host galaxy properties.

1.Investigating the Correlation of Outflow Kinematics with Radio Activity. Gas Outflows in AGNs. VII

Authors:Ashraf Ayubinia, Jong-Hak Woo, Suvendu Rakshit, Donghoon Son

Abstract: We explore the relationship between the ionized gas outflows and radio activity using a sample of $\sim$ 6000 AGNs at z < 0.4 with the kinematical measurement based on the [O III] line profile and the radio detection in the VLA FIRST Survey. To quantify radio activity, we divide our sample into a series of binary subclasses based on the radio properties, i.e., radio-luminous/radio-weak, AGN-dominated/star-formation-contaminated, compact/extended, and radio-loud/radio-quiet. None of the binary subclasses exhibits a significant difference in the normalized [O III] velocity dispersion at a given [O III] luminosity once we correct for the influence of the host galaxy gravitational potential. We only detect a significant difference of [O III] kinematics between high and low radio-Eddington ratio (L$_{1.4 GHz}$/L$_{Edd}$) AGNs. In contrast, we find a remarkable difference in ionized gas kinematics between high and low bolometric-Eddington ratio AGNs. These results suggest that accretion rate is the primary mechanism in driving ionized gas outflows, while radio activity may play a secondary role providing additional influence on gas kinematics

2.ViCTORIA project: MeerKAT HI observations of the ram pressure stripped galaxy NGC 4523

Authors:A. Boselli, P. Serra, F. de Gasperin, B. Vollmer, P. Amram, H. W. Edler, M. Fossati, G. Consolandi, P. Cote, J. C. Cuillandre, L. Ferrarese, S. Gwyn, J. Postma, M. Boquien, J. Braine, F. Combes, G. Gavazzi, G. Hensler, M. A. Miville-Deschenes, M. Murgia, J. Roediger, Y. Roehlly, R. Smith, H. X. Zhang, N. Zabel

Abstract: We present the first results of a 21 cm HI line pilot observation carried out with MeerKAT in preparation for the ViCTORIA project, an untargeted survey of the Virgo galaxy cluster. The extraordinary quality of the data in terms of sensitivity and angular resolution (rms~0.65 mJy beam^-1 at ~27"x39" and 11 km/s resolution) allowed us to detect an extended (~10 kpc projected length) low column density (N(HI) < 2.5x10^20 cm^-2) HI gas tail associated with the dwarf irregular galaxy NGC4523 at the northern edge of the cluster. The morphology of the tail and of the stellar disc suggest that the galaxy is suffering a hydrodynamic interaction with the surrounding hot intracluster medium (ICM; ram pressure stripping). The orientation of the trailing tail, the gradient in the HI gas column density at the interface between the cold ISM and the hot ICM, the velocity of the galaxy with respect to that of the cluster, and its position indicate that NGC4523 is infalling for the first time into Virgo from the NNW background of the cluster. Using a grid of hydrodynamic simulations we derive the impact parameters with the surrounding ICM, and estimate that the galaxy will be at pericentre (D~500-600 kpc) in ~1 Gyr, where ram pressure stripping will be able to remove most, if not all, of its gas. The galaxy is located on the star formation main sequence when its star formation rate is derived using Halpha images obtained during the VESTIGE survey, suggesting that NGC4523 is only at the beginning of its interaction with the surrounding environment. A few HII regions are detected in the Halpha images within the HI gas tail outside the stellar disc. Their ages, derived by comparing their Halpha, FUV, NUV, and optical colours with the predictions of SED fitting models, are <30 Myr, and suggest that these HII regions have formed within the stripped gas.

3.Similar levels of deuteration in the pre-stellar core L1544 and the protostellar core HH211

Authors:K. Giers, S. Spezzano, P. Caselli, E. Wirström, O. Sipilä, J. E. Pineda, E. Redaelli, C. T. Bop, F. Lique

Abstract: In the centre of pre-stellar cores, deuterium fractionation is enhanced due to the low temperatures and high densities. Therefore, the chemistry of deuterated molecules can be used to study the earliest stages of star formation. We analyse the deuterium fractionation of simple molecules, comparing the level of deuteration in the envelopes of the pre-stellar core L1544 in Taurus and the protostellar core HH211 in Perseus. We used single-dish observations of CCH, HCN, HNC, HCO$^+$, and their $^{13}$C-, $^{18}$O- and D-bearing isotopologues, detected with the Onsala 20m telescope. We derived the column densities and the deuterium fractions of the molecules. Additionally, we used radiative transfer simulations and results from chemical modelling to reproduce the observed molecular lines. We used new collisional rate coefficients for HNC, HN$^{13}$C, DNC, and DCN that consider the hyperfine structure of these molecules. We find high levels of deuteration for CCH (10%) in both sources, consistent with other carbon chains, and moderate levels for HCN (5-7%) and HNC (8%). The deuterium fraction of HCO$^+$ is enhanced towards HH211, most likely caused by isotope-selective photodissociation of C$^{18}$O. Similar levels of deuteration show that the process is likely equally efficient towards both cores, suggesting that the protostellar envelope still retains the chemical composition of the original pre-stellar core. The fact that the two cores are embedded in different molecular clouds also suggests that environmental conditions do not have a significant effect on the deuteration within dense cores. Radiative transfer modelling shows that it is necessary to include the outer layers of the cores to consider the effects of extended structures. Besides HCO$^+$ observations, HCN observations towards L1544 also require the presence of an outer diffuse layer where the molecules are relatively abundant.

4.Fantastic Fits with fantasy of Active Galactic Nuclei Spectra -- Exploring the Fe II emission near the H$α$ line

Authors:Dragana Ilic, Nemanja Rakic, Luka C. Popovic

Abstract: In this study, a refined approach for multicomponent fitting of active galactic nuclei (AGN) spectra is presented utilizing the newly developed Python code $fantasy$ (fully automated python tool for AGN spectra analysis). AGN spectra are modeled by simultaneously considering the underlying broken power-law continuum, predefined emission line lists, and an Fe II model, which is here extended to cover the wavelength range 3700 - 11000 A. The Fe II model, founded solely on atomic data, effectively describes the extensive emission of the complex iron ion in the vicinity of the H$\gamma$ and H$\beta$ lines, as well as near the H$\alpha$ line, which was previously rarely studied. The proposed spectral fitting approach is tested on a sample of high-quality AGN spectra from the Sloan Digital Sky Survey (SDSS) Data Release 17. The results indicate that when Fe II emission is present near H$\beta$, it is also detected redward from H$\alpha$, potentially contaminating the broad H$\alpha$ line wings and thus affecting the measurements of its flux and width. The production of Fe II emission is found to be strongly correlated with Eddington luminosity and appears to be controlled by the similar mechanism as the hydrogen Balmer lines. The study highlights the benefits of fitting AGN type 1 spectra with the $fantasy$ code, pointing that it may be used as a robust tool for analyzing a large number of AGN spectra in the coming spectral surveys.

5.An Enhanced Massive Black Hole Occupation Fraction Predicted in Cluster Dwarf Galaxies

Authors:Michael Tremmel, Angelo Ricarte, Priyamvada Natarajan, Jillian Bellovary, Ramon Sharma, Thomas R. Quinn

Abstract: The occupation fraction of massive black holes (MBHs) in low mass galaxies offers interesting insights into initial black hole seeding mechanisms and their mass assembly history, though disentangling these two effects remains challenging. Using the Romulus cosmological simulations we examine the impact of environment on the occupation fraction of MBHs in low mass galaxies. Unlike most modern cosmological simulations, Romulus seeds MBHs based on local gas properties, selecting very dense, pristine, and rapidly collapsing regions in the early Universe as sites to host MBHs without assuming anything about MBH occupation as a function of galaxy stellar mass, or halo mass, a priori. The simulations predict that dwarf galaxies with M$_{\star}<10^9$ M$_{\odot}$ in cluster environments are approximately two times more likely to host a MBH compared to those in the field. The predicted occupation fractions are remarkably consistent with those of nuclear star clusters. Across cluster and field environments, dwarf galaxies with earlier formation times are more likely to host a MBH. Thus, while the MBH occupation function is similar between cluster and field environments at high redshift ($z>3$), a difference arises as late-forming dwarfs -- which do not exist in the cluster environment -- begin to dominate in the field and pull the MBH occupation fraction down for low mass galaxies. Additionally, prior to in-fall some cluster dwarfs are similar to progenitors of massive, isolated galaxies, indicating that they might have grown to higher masses had they not been impeded by the cluster environment. While the population of MBHs in dwarf galaxies is already widely understood to be important for understanding MBH formation, this work demonstrates that environmental dependence is important to consider as future observations search for low mass black holes in dwarf galaxies.

6.The Galactic Extinction Horizon with Present and Future Surveys

Authors:Dante Minniti

Abstract: We have made a lot of progress in the study of the MW. In spite of this, much of our Galaxy remains unknown, and amazing breakthroughs await to be made in the exploration of the far side of the Galaxy. Focussing on the Galactic extinction horizon problem with current surveys like the Two Micron All-Sky Survey (2MASS) and the Vista Variables in the Via Lactea Survey (VVV) and its extension VVVX, the extinction horizon is a fundamental difficulty, and it is my intention here to reveal how profound is our ignorance, and also to try to suggest ways for improvement with future near-IR Galactic surveys.

7.Mapping non-axisymmetric velocity fields of external galaxies

Authors:Francesco Sylos Labini, Matteo Straccamore, Giordano De Marzo, Sébastien Comeròn

Abstract: Disk galaxies are typically in a stable configuration where matter moves in almost closed circular orbits. However, non-circular motions caused by distortions, warps, lopsidedness, or satellite interactions are common and leave distinct signatures on galaxy velocity maps. We develop an algorithm that uses an ordinary least square method for fitting a non-axisymmetric model to the observed two-dimensional line-of-sight velocity map of an external galaxy, which allows for anisotropic non-circular motions. The method approximates a galaxy as a flat disk, which is an appropriate assumption for spiral galaxies within the optical radius where warps are rare. In the outer parts of HI distributions, which may extend well into the warp region, we use this method in combination with a standard rotating tilted ring model to constrain the range of radii where the flat disk assumption can be conservatively considered valid. Within this range, the transversal and radial velocity profiles, averaged in rings, can be directly reconstructed from the velocity map. The novelty of the algorithm consists in using arc segments in addition to rings: in this way spatial velocity anisotropies can be measured in both components, allowing for the reconstruction of angularly resolved coarse-grained two-dimensional velocity maps. We applied this algorithm to 25 disk galaxies from the THINGS sample for which we can provide 2D maps of both velocity components.

8.Deficit of Hot Dust in Low-redshift Active Galactic Nuclei

Authors:Suyeon Son, Minjin Kim, Luis C. Ho

Abstract: We assemble a broad-band spectral energy distribution (SED) ranging from optical to mid-infrared of nearby active galactic nuclei at $z < 0.4$. SED fitting analysis is performed using semi-empirical templates derived from Palomar-Green quasars to classify the sample into normal, warm-dust-deficient (WDD), and hot-dust-deficient (HDD) AGNs. Kolmogorov-Smirnov tests reveal that HDD AGNs exhibit, on average higher AGN luminosity than normal and WDD AGNs. HDD fraction, on the other hand, is only weakly correlated with black hole mass and inversely correlated with Eddington ratio. By fixing the other parameters, we conclude that the HDD fraction is primarily connected with the AGN luminosity. It implies that there is a causal connection between the covering factor of the hot dust component and AGN luminosity, possibly due to the sublimation of the innermost dust or the thickening of the intervening gas in the broad-line region. Analysis of the outflow properties traced by the wing of [O III]$\lambda5007$ suggests that outflows may be related to the formation and maintenance of the hot dust component. Finally, we demonstrate through comparison with previous studies that the classification of HDD AGNs requires careful subtraction of the host galaxy light.

9.Star cluster formation and feedback in different environments of a Milky Way-like galaxy

Authors:Ahmad A. Ali, Clare L. Dobbs, Thomas J. R. Bending, Anne S. M. Buckner, Alex R. Pettitt

Abstract: It remains unclear how galactic environment affects star formation and stellar cluster properties. This is difficult to address in Milky Way-mass galaxy simulations because of limited resolution and less accurate feedback compared to cloud-scale models. We carry out zoom-in simulations to re-simulate 100-300 pc regions of a Milky Way-like galaxy using smoothed particle hydrodynamics, including finer resolution (0.4 Msun per particle), cluster-sink particles, ray-traced photoionization from O stars, H$_2$/CO chemistry, and ISM heating/cooling. We select $10^6$ Msun cloud complexes from a galactic bar, inner spiral arm, outer arm, and inter-arm region (in order of galactocentric radius), retaining the original galactic potentials. The surface densities of star formation rate and neutral gas follow $\Sigma_{SFR} \propto \Sigma_{gas}^{1.3}$, with the bar lying higher up the relation than the other regions. However, the inter-arm region forms stars 2-3x less efficiently than the arm models at the same $\Sigma_{gas}$. The bar produces the most massive cluster, the inner arm the second, and the inter-arm the third. Almost all clusters in the bar and inner arm are small (radii < 5 pc), while 30-50 per cent of clusters in the outer arm and inter-arm have larger radii more like associations. Bar and inner arm clusters rotate at least twice as fast, on average, than clusters in the outer arm and inter-arm regions. The degree of spatial clustering also decreases from bar to inter-arm. Our results indicate that young massive clusters, potentially progenitors of globular clusters, may preferentially form near the bar/inner arm compared to outer arm/inter-arm regions.

10.Shock cooling of a red-supergiant supernova at redshift 3 in lensed images

Authors:Wenlei Chen, Patrick L. Kelly, Masamune Oguri, Thomas J. Broadhurst, Jose M. Diego, Najmeh Emami, Alexei V. Filippenko, Tommaso L. Treu, Adi Zitrin

Abstract: The core-collapse supernova of a massive star rapidly brightens when a shock, produced following the collapse of its core, reaches the stellar surface. As the shock-heated star subsequently expands and cools, its early-time light curve should have a simple dependence on the progenitor's size and therefore final evolutionary state. Measurements of the progenitor's radius from early light curves exist for only a small sample of nearby supernovae, and almost all lack constraining ultraviolet observations within a day of explosion. The several-day time delays and magnifying ability of galaxy-scale gravitational lenses, however, should provide a powerful tool for measuring the early light curves of distant supernovae, and thereby studying massive stellar populations at high redshift. Here we analyse individual rest-frame ultraviolet-through-optical exposures taken with the Hubble Space Telescope that simultaneously capture, in three separate gravitationally lensed images, the early phases of a supernova at redshift $z \approx 3$ beginning within $5.8\pm 3.1$ hr of explosion. The supernova, seen at a lookback time of $\sim11.5$ billion years, is strongly lensed by an early-type galaxy in the Abell 370 cluster. We constrain the pre-explosion radius to be $533^{+154}_{-119}$ solar radii, consistent with a red supergiant. Highly confined and massive circumstellar material at the same radius can also reproduce the light curve, but is unlikely since no similar low-redshift examples are known.

11.Spatially Resolved Kinematics of Extraplanar Diffuse Ionized Gas in NGC$\,$3511 and NGC$\,$3513

Authors:Hanjue Zhu, Erin Boettcher, Hsiao-Wen Chen

Abstract: Gaseous, disk-halo interfaces are shaped by physical processes that are critical to disk galaxy evolution, including gas accretion and galactic outflows. However, observations indicate that extraplanar diffuse ionized gas (eDIG) layers have scale heights several times higher than their thermal scale heights. This discrepancy poses a challenge to our current understanding of the disk-halo interface. In this paper, we present a spatially-resolved case study of the eDIG layers in a nearby pair of sub-$L_*$ disk galaxies NGC$\,$3511/3513 using long-slit spectroscopy. We decompose optical nebular lines from the warm interstellar medium and disk-halo interfaces into narrow and broad velocity components. We show that in NGC$\,$3511, the broad component has three distinctive characteristics in comparison to the narrow component: (1) elevated [NII]$\lambda 6583/H\alpha$ and [SII]$\lambda 6716/H\alpha$ line ratios, (2) significantly higher velocity dispersions (a median $\langle\sigma\rangle_{\text{Broad}} = 24\,$km/s compared to $\langle\sigma\rangle_{\text{Narrow}} = 13\,$km/s), and (3) a rotational velocity lag. Together, these characteristics support an origin in an extraplanar, thick gaseous disk. In NGC$\,$3513, the broad component is consistent with localized outflows making their way out of the galactic disk. Our findings demonstrate that gas circulation at the disk-halo interface is present in both galaxies. Additionally, we test a dynamic equilibrium model with pressure support supplied by thermal and turbulent motions. Based on measurements of the eDIG velocity dispersion in NGC$\,$3511, we demonstrate that turbulent motions increase the scale height by at least a factor of a few above the thermal scale height, with $h_{z} \gtrsim 0.2 - 0.4$ kpc at $R = 3 - 5$ kpc. This highlights the importance of turbulent motions to the vertical structure of the gaseous, disk-halo interface.

12.Magellanic System Stars Identified in the SMACS J0723.3-7327 JWST ERO Images

Authors:Jake Summers, Rogier A. Windhorst, Seth H. Cohen, Rolf A. Jansen, Timothy Carleton, Patrick S. Kamieneski, Benne W. Holwerda, Christopher J. Conselice, Nathan J. Adams, Brenda Frye, Jose M. Diego, Christopher N. A. Willmer, Rafael Ortiz III, Cheng Cheng, Alex Pigarelli, Aaron Robotham, Jordan C. J. D'Silva, Scott Tompkins, Simon P. Driver, Haojing Yan, Dan Coe, Norman Grogin, Anton Koekemoer, Madeline A. Marshall, Nor Pirzkal, Russell E. Ryan Jr

Abstract: We identify 68 distant stars in JWST/NIRCam ERO images of the field of galaxy cluster SMACS J0723.3-7327 (SMACS 0723). Given the relatively small ($\sim$$10^{\circ}$) angular separation between SMACS 0723 and the Large Magellanic Cloud, it is likely that these stars are associated with the LMC outskirts or Leading Arm. This is further bolstered by a spectral energy distribution analysis, which suggests an excess of stars at a physical distance of $40-100$ kpc, consistent with being associated with or located behind the Magellanic system. In particular, we find that the overall surface density of stars brighter than 27.0 mag in the field of SMACS 0723 is $\sim$2.3 times that of stars in a blank field with similar galactic latitude (the North Ecliptic Pole Time Domain Field), and that the density of stars in the SMACS 0723 field with SED-derived distances consistent with the Magellanic system is $\sim$7.3 times larger than that of the blank field. The candidate stars at these distances are consistent with a stellar population at the same distance modulus with [Fe/H] $= -1.0$ and an age of $\sim$$5.0$ Gyr. On the assumption that all of the 68 stars are associated with the LMC, then the stellar density of the LMC at the location of the SMACS 0723 field is $\sim$$710$ stars kpc$^{-3}$, which helps trace the density of stars in the LMC outskirts.

1.Newly Discovered Wolf-Rayet Stars in M31

Authors:Kathryn F. Neugent, Philip Massey

Abstract: The evolved massive star populations of the Local Group galaxies are generally thought to be well-understood. However, recent work suggested that the Wolf-Rayet (WR) content of M31 may have been underestimated. We therefore began a pilot project to search for new WRs in M31 and re-examine the completeness of our previous WR survey finished almost a decade prior. Our improved imaging data and spectroscopic follow-up confirmed 19 new WRs across three small fields in M31. These newly discovered WRs are generally fainter than the previously known sample due to slightly increased reddening as opposed to intrinsic faintness. From these findings, we estimate that there are another ~60 WRs left to be discovered in M31; however, the overall ratio of WN-type (nitrogen-rich) to WC-type (carbon-rich) WRs remains unchanged with our latest additions to the M31 WR census. We are in the process of extending this pilot WR survey to include the rest of M31, and a more complete population will be detailed in our future work.

2.Formation of first star clusters under the supersonic gas flow -- I. Morphology of the massive metal-free gas cloud

Authors:Shingo Hirano The University of Tokyo, Youcheng Shen The University of Tokyo, Sho Nishijima The University of Tokyo, Yusuke Sakai The University of Tokyo, Hideyuki Umeda The University of Tokyo

Abstract: We performed $42$ simulations of the first star formation with initial supersonic gas flows relative to the dark matter at the cosmic recombination era. Increasing the initial streaming velocities led to delayed halo formation and increased halo mass, enhancing the mass of the gravitationally shrinking gas cloud. For more massive gas clouds, the rate of temperature drop during contraction, in other words, the structure asymmetry, becomes more significant. When the maximum and minimum gas temperature ratios before and after contraction exceed about ten, the asymmetric structure of the gas cloud prevails, inducing fragmentation into multiple dense gas clouds. We continued our simulations until $10^5$ years after the first dense core formation to examine the final fate of the massive star-forming gas cloud. Among the $42$ models studied, we find the simultaneous formation of up to four dense gas clouds, with a total mass of about $2254\,M_\odot$. While the gas mass in the host halo increases with increasing the initial streaming velocity, the mass of the dense cores does not change significantly. The star formation efficiency decreases by more than one order of magnitude from $\epsilon_{\rm III} \sim 10^{-2}$ to $10^{-4}$ when the initial streaming velocity, normalised by the root mean square value, increases from 0 to 3.

3.Early Structure Formation from Primordial Density Fluctuations with a Blue, Tilted Power Spectrum -- II. High-Redshift Galaxies

Authors:Shingo Hirano The University of Tokyo, Naoki Yoshida The University of Tokyo

Abstract: The first series of observations by the James Webb Space Telescope (JWST) discovered unexpectedly abundant luminous galaxies at high redshift, posing possibly a serious challenge to popular galaxy formation models. We study early structure formation in a cosmological model with a blue, tilted power spectrum (BTPS) given by $P(k) \propto k^{m_{\rm s}}$ with $m_{\rm s} > 1$ at small length scales. We run a set of cosmological $N$-body simulations and derive the abundance of dark matter halos and of galaxies under simplified assumptions on star formation efficiency. The enhanced small-scale power allows rapid formation of nonlinear structure at $z>7$, and galaxies with stellar mass exceeding $10^{10}\,M_\odot$ can be formed by $z=9$. Because of frequent mergers, the structure of galaxies and galaxy groups appears overall clumpy. The BTPS model reproduces the observed stellar mass density at $z=7-9$, and thus eases the claimed tension between galaxy formation theory and recent JWST observations. Large-scale structure of the present-day Universe is largely unaffected by the modification of the small-scale power spectrum. Finally, we discuss the formation of the first stars and early super-massive black holes in the BTPS model.

1.The magnetic fields around the cometary globules, L328, L323 and L331

Authors:Siddharth Kumar, Archana Soam, Nirupam Roy

Abstract: This work presents the magnetic field geometry in a complex of three cometary (with head-tail morphology) globules, namely LDN 323, LDN 328, and LDN 331, using R-band polarization measurements of background stars. These observations were combined with a Planck sky survey to study the large-scale morphology of the magnetic fields in the region. The distances of the target stars were adopted from the Gaia catalog. The variation of degree of polarization and polarization position angle with distances of stars is analyzed. The field geometry is mostly found to follow the cometary shape of the cloud, with some randomness at certain locations. For studying the correlation between cloud morphology and magnetic field orientations, a modified version of the Histogram of Relative Orientation analysis was employed.

2.AGN and Star Formation feedback in the evolution of galaxy outflows

Authors:William E. Clavijo-Bohórquez, Elisabete M. de Gouveia Dal Pino, Claudio Melioli

Abstract: We conducted 3D-MHD simulations to investigate the feedback processes in the central 1kpc scale of galaxies hosting both active star formation (SF) and an AGN wind. Our simulations naturally generated a turbulent and clumpy interstellar medium driven by SF evolution. We found that the AGN wind duty cycle plays a crucial role in shaping the evolution of the outflows. This cycle consists of an active, a remnant and an inactive phase, lasting up to 1.5 Myr. The duration of the cycle increases with larger star formation rate (SFR) and smaller AGN wind power (tested for luminosities log L = 42-44 ergs per second and SFR=1-1000 solar masses per year. The feedback on SF, whether positive or negative, depends on various factors, including the AGN outflow opening angle, power, and phase of activity, as well as the initial SFR. The passage of the AGN wind enhances SF in a ring around it, resembling the structures observed in ULIRGs, and is stronger for larger AGN power or SFR. Also, a higher SFR enhances the mixing of interstellar matter with the AGN wind, resulting in a greater number of colder, denser structures with volume filling factors ~ 0.02 to 0.12 and velocities comparable to those observed in Seyferts and LINERs, but smaller than those observed in ULIRGs. The efficiency of the AGN wind in transporting mass to kiloparsec distances diminishes with increasing SFR. The mass loss rates range from 50 to 250 solar masses per year within the initial 2 Myr of evolution, which aligns with observed rates in nearby Seyferts and ULIRGs.

3.A high-resolution extinction mapping technique for face-on disc galaxies

Authors:Helena Faustino Vieira, Ana Duarte-Cabral, Timothy A. Davis, Nicolas Peretto, Matthew W. L. Smith, Miguel Querejeta, Dario Colombo, Michael Anderson

Abstract: We present a new dust extinction technique with which we are able to retrieve parsec-scale gas surface density maps for entire nearby galaxies. The method measures the dust attenuation in optical bands on a pixel-by-pixel basis against a smoothed, reconstructed stellar distribution. The contribution of foreground light along the line-of-sight is calibrated using dust emission observations, assuming that the dust sits in a layer close to the mid-plane of the face-on galaxy. Here, we apply this technique to M51 (NGC 5194) as a proof-of-concept, obtaining a resolution of 0.14" (5 pc). Our dust (and gas) surface density map is consistent with independent dust- and CO-based studies at lower resolution. We find that discrepancies between our estimates of surface density and other studies stem primarily from the choice of dust model (i.e. different dust absorption coefficients). When assuming the same dust opacity law, our technique produces surface densities that are consistent with independent studies. This dust extinction technique provides us with gas surface density maps at an unprecedented resolution for full disc coverage studies of nearby galaxies. The resulting well-resolved spatial information opens the possibility for more in-depth examination of the influence of large-scale dynamics (and also stellar feedback mechanisms) on the interstellar medium at parsec-scales, and consequently star formation in nearby galaxies.

4.A Machine Learning Approach to Galactic Emission-Line Region Classification

Authors:Carter Lee Rhea, Laurie Rousseau-Nepton, Ismael Moumen, Simon Prunet, Julie Hlavacek-Larrondo, Kathryn Grasha, Carmelle Roberts, Christophe Morisset, Grazyna Stasinska, Natalia Vale-Asari, Justine Giroux, Anna McLeod, Marie-Lou Gendron-Marsolais, Junfeng Wang, Joe Lyman, Laurent Chemin

Abstract: Diagnostic diagrams of emission-line ratios have been used extensively to categorize extragalactic emission regions; however, these diagnostics are occasionally at odds with each other due to differing definitions. In this work, we study the applicability of supervised machine-learning techniques to systematically classify emission-line regions from the ratios of certain emission lines. Using the Million Mexican Model database, which contains information from grids of photoionization models using \texttt{cloudy}, and from shock models, we develop training and test sets of emission line fluxes for three key diagnostic ratios. The sets are created for three classifications: classic \hii{} regions, planetary nebulae, and supernova remnants. We train a neural network to classify a region as one of the three classes defined above given three key line ratios that are present both in the SITELLE and MUSE instruments' band-passes: [{\sc O\,iii}]$\lambda5007$/H$\beta$, [{\sc N\,ii}]$\lambda6583$/H$\alpha$, ([{\sc S\,ii}]$\lambda6717$+[{\sc S\,ii}]$\lambda6731$)/H$\alpha$. We also tested the impact of the addition of the [{\sc O\,ii}]$\lambda3726,3729$/[{\sc O\,iii}]$\lambda5007$ line ratio when available for the classification. A maximum luminosity limit is introduced to improve the classification of the planetary nebulae. Furthermore, the network is applied to SITELLE observations of a prominent field of M33. We discuss where the network succeeds and why it fails in certain cases. Our results provide a framework for the use of machine learning as a tool for the classification of extragalactic emission regions. Further work is needed to build more comprehensive training sets and adapt the method to additional observational constraints.

5.Obtaining strength of magnetic field from E and B modes of dust polarization

Authors:Jungyeon Cho

Abstract: We perform numerical simulations of supersonic magnetohydrodynamic (MHD) turbulence and calculate Fourier power spectra of E and B modes arising from dust polarization. We pay close attention to the ratio of E-mode to B-mode spectra (a.k.a. E/B power asymmetry) on small spatial scales. We find that the ratio depends on the strength of the mean magnetic field: the stronger the mean magnetic field is, the smaller the ratio is. More precisely speaking, the ratio scales with the Alfv\'en Mach number $M_A$, the root-mean-square velocity divided by the Alfv\'en speed of the mean magnetic field, when it lies in the range $1\lesssim M_A \lesssim 30$. This result implies that we can use the E/B power asymmetry to constrain the strength of the mean magnetic field in supersonic and super-Alfv\'enic MHD turbulence.

6.Chemodynamical models of our Galaxy

Authors:James Binney, Eugene Vasiliev

Abstract: A chemodynamical model of our galaxy is fitted to data from DR17 of the APOGEE survey supplemented with data from the StarHorse catalogue and gaia DR3. Dynamically, the model is defined by action-based distribution functions for dark matter and six stellar components plus a gas disc. The gravitational potential jointly generated by the model's components is used to examine the galaxy's chemical composition within action space. The observational data probably cover all parts of action space that are populated by stars. The overwhelming majority of stars have angular momentum J_\phi>0 implying that they were born in the Galactic disc. High-alpha stars dominate in a region that is sharply bounded by J_\phi \la J_\phi(solar). Chemically the model is defined by giving each stellar component a Gaussian distribution in ([Fe/H],[Mg/Fe]) space about a mean that is a linear function of the actions. The model's 47 dynamical and 70 chemical parameters are chosen to maximise the likelihood of the data given the model in 72 three-dimensional velocity spaces and 30 two-dimensional chemical spaces. The circular speed falls steadily from 237\kms at R=4\kpc to 218\kms at R=20\kpc. Dark matter contributes half the radial force on the Sun and has local density 0.011\msun\pc^{-3}, there being 24.5\msun\pc^{-2} in dark matter and 26.5\msun\pc^{-2} in stars within 1.1\kpc of the plane.

7.Detectability of Supermassive Dark Stars with the Roman Space Telescope

Authors:Saiyang Zhang, Cosmin Ilie, Katherine Freese

Abstract: The first bright objects to form in the Universe at redshift $z \sim 10-20$ might have been Dark Stars, made primarily of hydrogen and helium but powered by dark matter. In this study, we investigate the detectability of Supermassive Dark Stars (SMDS) by the Roman Space Telescope. RST will be able to detect SMDSs at redshifts as high as $z\simeq 14$. In cases with gravitational lensing factors of $\mu\sim 100$, RST will be able to find SMDS as small as $\sim10^4 M_{\odot}$ at $z\sim 12$ with $\sim 10^6$ s of exposure. To differentiate SMDS from early galaxies containing zero metallicity stars at similar redshifts, we compare their spectra, photometry in RST bands, color indexes and image morphology. With RST alone, the differentiation is possible only for limited cases: SMDS formed via "adiabatic contraction" (DM pulled into the star via gravity alone) with $M\gtrsim 10^5M_{\odot}$ and lensed by $\mu\gtrsim 30$ have distinct photometric signatures from those of the first galaxies. For SMDSs formed via "dark matter capture," their spectra are degenerate to those of many galaxies with little to no nebular emission. Thus with RST alone, the only way to tell them apart from first galaxies would be via image morphology: i.e. point object (SMDSs) vs. extended object (sufficiently magnified galaxies). However, if the same objects are further examined by JWST spectroscopy, a "smoking gun" for detection of SMDS is the HeII $\lambda$1640 absorption line. While RST does not cover the wavelength band required to find this line (for $z_{\rm emi}\gtrsim 10$), JWST does. Hence the two detectors can be used together in identifying SMDS. The confirmed detection of any SMDSs will provide evidence for a new type of star, powered by dark matter. Moreover, such massive stars can also be natural progenitors of the supermassive black holes powering the extremely bright quasars observed at $z\gtrsim 6$.

8.Neural Astrophysical Wind Models

Authors:Dustin D. Nguyen

Abstract: The bulk kinematics and thermodynamics of hot supernovae-driven galactic winds is critically dependent on both the amount of swept up cool clouds and non-spherical collimated flow geometry. However, accurately parameterizing these physics is difficult because their functional forms are often unknown, and because the coupled non-linear flow equations contain singularities. We show that deep neural networks embedded as individual terms in the governing coupled ordinary differential equations (ODEs) can robustly discover both of these physics, without any prior knowledge of the true function structure, as a supervised learning task. We optimize a loss function based on the Mach number, rather than the explicitly solved-for 3 conserved variables, and apply a penalty term towards near-diverging solutions. The same neural network architecture is used for learning both the hidden mass-loading and surface area expansion rates. This work further highlights the feasibility of neural ODEs as a promising discovery tool with mechanistic interpretability for non-linear inverse problems.

9.Investigating the Dark Matter Halo of NGC 5128 using a Discrete Dynamical Model

Authors:Antoine Dumont, Anil C. Seth, Jay Strader, David J. Sand, Karina Voggel, Allison K. Hughes, Denija Crnojević, Duncan A. Forbes, Mario Mateo, Sarah Pearson

Abstract: As the nearest accessible massive early-type galaxy, NGC 5128 presents an exceptional opportunity to measure dark matter halo parameters for a representative elliptical galaxy. Here we take advantage of rich new observational datasets of large-radius tracers to perform dynamical modeling of NGC 5128, using a discrete axisymmetric anisotropic Jeans approach with a total tracer population of nearly 1800 planetary nebulae, globular clusters, and dwarf satellite galaxies extending to a projected distance of $\sim250$ kpc from the galaxy center. We find that a standard NFW halo provides an excellent fit to nearly all the data, excepting a subset of the planetary nebulae that appear to be out of virial equilibrium. The best-fit dark matter halo has a virial mass of ${\rm M}_{vir}=4.4^{+2.4}_{-1.4}\times10^{12} {\rm M}_{\odot}$, and NGC 5128 appears to sit below the mean stellar mass--halo mass and globular cluster mass--halo mass relations, which both predict a halo virial mass closer to ${\rm M}_{vir} \sim 10^{13} {\rm M}_{\odot}$. The inferred NFW virial concentration is $c_{vir}=5.6^{+2.4}_{-1.6}$, nominally lower than $c_{vir} \sim 9$ predicted from published $c_{vir}$--${\rm M}_{vir}$ relations, but within the $\sim 30\%$ scatter found in simulations. The best-fit dark matter halo constitutes only $\sim10\%$ of the total mass at 1 effective radius but $\sim50\%$ at 5 effective radii. The derived halo parameters are relatively insensitive to reasonable variations in the tracer population considered, tracer anisotropies, and system inclination. Our analysis highlights the value of comprehensive dynamical modeling of nearby galaxies, and the importance of using multiple tracers to allow cross-checks for model robustness.

10.Galactic coronae in Milky Way-like galaxies: the role of stellar feedback in gas accretion

Authors:Filippo Barbani, Raffaele Pascale, Federico Marinacci, Laura V. Sales, Mark Vogelsberger, Paul Torrey, Hui Li

Abstract: Star-forming galaxies like the Milky Way are surrounded by a hot gaseous halo at the virial temperature - the so-called galactic corona - that plays a fundamental role in their evolution. The interaction between the disc and the corona has been shown to have a direct impact on accretion of coronal gas onto the disc with major implications for galaxy evolution. In this work, we study the gas circulation between the disc and the corona of star-forming galaxies like the Milky Way. We use high-resolution hydrodynamical N-body simulations of a Milky Way-like galaxy with the inclusion of an observationally-motivated galactic corona. In doing so, we use SMUGGLE, an explicit interstellar medium (ISM) and stellar feedback model coupled with the moving-mesh code Arepo. We find that the reservoir of gas in the galactic corona is sustaining star formation: the gas accreted from the corona is the primary fuel for the formation of new stars, helping in maintaining a nearly constant level of cold gas mass in the galactic disc. Stellar feedback generates a gas circulation between the disc and the corona (the so-called galactic fountain) by ejecting different gas phases that are eventually re-accreted onto the disc. The accretion of coronal gas is promoted by its mixing with the galactic fountains at the disc-corona interface, causing the formation of intermediate temperature gas that enhance the cooling of the hot corona. We find that this process acts as a positive feedback mechanism, increasing the accretion rate of coronal gas onto the galaxy.

11.Cosmic evolution of radio-AGN feedback: confronting models with data

Authors:R. Kondapally, P. N. Best, M. Raouf, N. L. Thomas, R. Davé, S. S. Shabala, H. J. A. Röttgering, M. J. Hardcastle, M. Bonato, R. K. Cochrane, K. Małek, L. K. Morabito, I. Prandoni, D. J. B. Smith

Abstract: Radio-mode feedback is a key ingredient in galaxy formation and evolution models, required to reproduce the observed properties of massive galaxies in the local Universe. We study the cosmic evolution of radio-AGN feedback out to $z\sim2.5$ using a sample of 9485 radio-excess AGN. We combine the evolving radio luminosity functions with a radio luminosity scaling relationship to estimate AGN jet kinetic powers and derive the cosmic evolution of the kinetic luminosity density, $\Omega_{\rm{kin}}$ (i.e. the volume-averaged heating output). Compared to all radio-AGN, low-excitation radio galaxies (LERGs) dominate the feedback activity out to $z\sim2.5$, with both these populations showing a constant heating output of $\Omega_{\rm{kin}} \approx 4-5 \times 10^{32}\,\rm{W\,Mpc^{-3}}$ across $0.5 < z < 2.5$. We compare our observations to predictions from semi-analytical and hydrodynamical simulations, which broadly match the observed evolution in $\Omega_{\rm{kin}}$, although their absolute normalisation varies. Comparison to the Semi-Analytic Galaxy Evolution (SAGE) model suggests that radio-AGN may provide sufficient heating to offset radiative cooling losses, providing evidence for a self-regulated AGN feedback cycle. We integrate the kinetic luminosity density across cosmic time to obtain the kinetic energy density output from AGN jets throughout cosmic history to be $\sim 10^{50}\,\rm{J\,Mpc^{-3}}$. Compared to AGN winds, the kinetic energy density from AGN jets dominates the energy budget at $z \lesssim 2$; this suggests that AGN jets play an important role in AGN feedback across most of cosmic history.

12.JADES: The incidence rate and properties of galactic outflows in low-mass galaxies across 3 < z < 9

Authors:Stefano Carniani, Giacomo Venturi, Eleonora Parlanti, Anna de Graaff, Roberto Maiolino, Santiago Arribas, Nina Bonaventura, Kristan Boyett, Andrew J. Bunker, Alex J. Cameron, Stephane Charlot, Jacopo Chevallard, Mirko Curti, Emma Curtis-Lake, Daniel J. Eisenstein, Giovanna Giardino, Ryan Hausen, Nimisha Kumari, Michael V. Maseda, Erica Nelson, Michele Perna, Hans-Walter Rix, Brant Robertson, Bruno Rodríguez Del Pino, Lester Sandles, Jan Scholtz, Charlotte Simmonds, Renske Smit, Sandro Tacchella, Hannah Übler, Christina C. Williams, Chris Willott, Joris Witstok

Abstract: We investigate the incidence and properties of ionized gas outflows in a sample of 52 galaxies with stellar mass between $10^7$ M$_{\odot}$ and $10^9$ M$_{\odot}$ observed with ultra-deep JWST/NIRSpec MSA spectroscopy as part of the JWST Advanced Deep Extragalactic Survey (JADES). The high-spectral resolution (R2700) NIRSpec observations allowed us to identify for the first time the signature of outflows in the rest-frame optical nebular lines in low-mass galaxies at $z>3$. The incidence fraction of ionized outflows, traced by broad components, is about 25-40$\%$ depending on the intensity of the emission lines. The low incidence fraction might be due to both the sensitivity limit and the fact that outflows are not isotropic but have a limited opening angle which results in a detection only when this is directed toward our line of sight. Evidence for outflows increases slightly with stellar mass and star-formation rate. The median velocity and mass loading factor (i.e., the ratio between mass outflow rate and star formation rate) of the outflowing ionized gas are 500 km s$^{-1}$ and $\eta=2.1^{+2.5}_{-1.6}$, respectively. These are two and 100 times higher, respectively than the typical values observed in local dwarf galaxies. These outflows are able to escape the gravitational potential of the galaxy and enrich the circum-galactic medium and, potentially, the inter-galactic medium. Our results indicate that outflows can significantly impact the star formation activity in low-mass galaxies within the first 2 Gyr of the Universe.

13.Calibrating mid-infrared emission as a tracer of obscured star formation on HII-region scales in the era of JWST

Authors:Francesco Belfiore, Adam K. Leroy, Thomas G. Williams, Ashley T. Barnes, Frank Bigiel, Médéric Boquien, Yixian Cao, Jérémy Chastenet, Enrico Congiu, Daniel A. Dale, Oleg V. Egorov, Cosima Eibensteiner, Eric Emsellem, Simon C. O. Glover, Brent Groves, Hamid Hassani, Ralf S. Klessen, Kathryn Kreckel, Lukas Neumann, Justus Neumann, Miguel Querejeta, Erik Rosolowsky, Patricia Sanchez-Blazquez, Karin Sandstrom, Eva Schinnerer, Jiayi Sun, Jessica Sutter, Elizabeth J. Watkins

Abstract: Measurements of the star formation activity on cloud scales are fundamental to uncovering the physics of the molecular cloud, star formation, and stellar feedback cycle in galaxies. Infrared (IR) emission from small dust grains and polycyclic aromatic hydrocarbons (PAHs) are widely used to trace the obscured component of star formation. However, the relation between these emission features and dust attenuation is complicated by the combined effects of dust heating from old stellar populations and an uncertain dust geometry with respect to heating sources. We use images obtained with NIRCam and MIRI as part of the PHANGS--JWST survey to calibrate dust emission at 21$\rm \mu m$, and the emission in the PAH-tracing bands at 3.3, 7.7, 10, and 11.3$\rm \mu m$ as tracers of obscured star formation. We analyse $\sim$ 16000 optically selected HII regions across 16 nearby star-forming galaxies, and benchmark their IR emission against dust attenuation measured from the Balmer decrement. We model the extinction-corrected H$\alpha$ flux as the sum of the observed H$\alpha$ emission and a term proportional to the IR emission, with $a_{IR}$ as the proportionality coefficient. A constant $a_{IR}$ leads to extinction-corrected H$\alpha$ estimates which agree with those obtained with the Balmer decrement with a scatter of $\sim$ 0.1 dex for all bands considered. Among these bands, 21$\rm \mu m$ emission is demonstrated to be the best tracer of dust attenuation. The PAH-tracing bands underestimate the correction for bright HII regions, since in these environments the ratio of PAH-tracing bands to 21$\rm \mu m$ decreases, signalling destruction of the PAH molecules. For fainter HII regions all bands suffer from an increasing contamination from the diffuse infrared background.

14.The Ages and Metallicities of the Globular Clusters in the Sparkler

Authors:Angela Adamo, Christopher Usher, Joel Pfeffer, Adélaïde Claeyssens

Abstract: JWST observations of the strongly lensed galaxy The Sparkler have revealed a population of gravitationally bound globular cluster (GC) candidates. Different analyses have resulted in broadly similar ages but significantly different metallicities, questioning the assembly history that has led to the formation of such a population. In this letter, we re-analyse the two sets of photometry available in the literature with the code MCMAME especially tailored to fit physical properties of GCs. We find the ages and metallicities from both datasets are consistent within 1 $\sigma$ uncertainties. A significant group of GCs is consistent with being old and metal poor ([Fe/H] $\sim -1.7$). For this group, the ages do not converge, hence, we conclude that they are definitively older than 1 Gyr and can be as old as the age of the Universe. The remaining GCs have younger ages and a metallicity spread. The ages and metallicities distribution of GCs in the Sparkler are consistent with those observed in Local Group's galaxies at similar lookback times. Comparing with predictions from E-MOSAICS simulations we confirm that the Sparkler GC population traces the self-enrichment history of a galaxy which might become a few times $10^9$ M$_{\odot}$ massive system at redshift $z = 0$

1.The MAGPI Survey: Impact of environment on the total internal mass distribution of galaxies in the last 5 Gyr

Authors:Caro Derkenne, Richard M. McDermid, Adriano Poci, J. Trevor Mendel, Francesco D'Eugenio, Seyoung Jeon, Rhea-Silvia Remus, Sabine Bellstedt, Andrew J. Battisti, Joss Bland-Hawthorn, Anna Ferre-Mateu, Caroline Foster, K. E. Harborne, Claudia D. P. Lagos, Yingjie Peng, Piyush Sharda, Gauri Sharma, Sarah Sweet, Kim-Vy H. Tran, Lucas M. Valenzuela, Sam Vaughan, Emily Wisnioski, Sukyoung K. Yi

Abstract: We investigate the impact of environment on the internal mass distribution of galaxies using the Middle Ages Galaxy Properties with Integral field spectroscopy (MAGPI) survey. We use 2D resolved stellar kinematics to construct Jeans dynamical models for galaxies at mean redshift $z \sim 0.3$, corresponding to a lookback time of $3-4$ Gyr. The internal mass distribution for each galaxy is parameterised by the combined mass density slope $\gamma$ (baryons $+$ dark matter), which is the logarithmic change of density with radius. We use a MAGPI sample of 28 galaxies from low-to-mid density environments and compare to density slopes derived from galaxies in the high density Frontier Fields clusters in the redshift range $0.29 <z < 0.55$, corresponding to a lookback time of $\sim 5$ Gyr. We find a median density slope of $\gamma = -2.22 \pm 0.05$ for the MAGPI sample, which is significantly steeper than the Frontier Fields median slope ($\gamma = -2.01 \pm 0.04$), implying the cluster galaxies are less centrally concentrated in their mass distribution than MAGPI galaxies. We also compare to the distribution of density slopes from galaxies in Atlas3D at $z \sim 0$, because the sample probes a similar environmental range as MAGPI. The Atlas3D median total slope is $\gamma = -2.25 \pm 0.02$, consistent with the MAGPI median. Our results indicate environment plays a role in the internal mass distribution of galaxies, with no evolution of the slope in the last 3-4 Gyr. These results are in agreement with the predictions of cosmological simulations.

2.X-ray Cavity Dynamics and their Role in the Gas Precipitation in Planck Sunyaev-Zeldovich (SZ) Selected Clusters

Authors:V. Olivares, Y. Su, W. Forman, M. Gaspari, F. Andrade-Santos, P. Salome, P. Nulsen, A. Edge, F. Combes, C. Jones

Abstract: We study active galactic nucleus (AGN) feedback in nearby (z<0.35) galaxy clusters from the Planck Sunyaev-Zeldovich (SZ) sample using Chandra observations. This nearly unbiased mass-selected sample includes both relaxed and disturbed clusters and may reflect the entire AGN feedback cycle. We find that relaxed clusters better follow the one-to-one relation of cavity power versus cooling luminosity, while disturbed clusters display higher cavity power for a given cooling luminosity, likely reflecting a difference in cooling and feedback efficiency. Disturbed clusters are also found to contain asymmetric cavities when compared to relaxed clusters, hinting toward the influence of the intracluster medium (ICM) weather on the distribution and morphology of the cavities. Disturbed clusters do not have fewer cavities than relaxed clusters, suggesting that cavities are difficult to disrupt. Thus, multiple cavities are a natural outcome of recurrent AGN outbursts. As in previous studies, we confirm that clusters with short central cooling times, tcool, and low central entropy values, K0, contain warm ionized (10000 K) or cold molecular (<100 K) gas, consistent with ICM cooling and a precipitation/chaotic cold accretion (CCA) scenario. We analyzed archival MUSE observations that are available for 18 clusters. In 11/18 of the cases, the projected optical line emission filaments appear to be located beneath or around the cavity rims, indicating that AGN feedback plays an important role in forming the warm filaments by likely enhancing turbulence or uplift. In the remaining cases (7/18), the clusters either lack cavities or their association of filaments with cavities is vague, suggesting alternative turbulence-driven mechanisms (sloshing/mergers) or physical time delays are involved.

3.Searching for Milky Way twins: Radial abundance distribution as a strict criterion

Authors:Pilyugin L. S., Tautvaisiene G., Lara-Lopez M. A

Abstract: We search for Milky Way-like galaxies among a sample of approximately 500 galaxies. The characteristics we considered of the candidate galaxies are the following: stellar mass M_star, optical radius R_25, rotation velocity V_rot, central oxygen abundance (O/H)_0, and abundance at the optical radius (O/H)_R25. If the values of R_25 and M_star of the galaxy were close to that of the Milky Way, then the galaxy was referred to as a structural Milky Way analogue (sMWA). The oxygen abundance at a given radius of a galaxy is defined by the evolution of that region, and we then assumed that the similarity of (O/H)_0 and (O/H)_R25 in two galaxies suggests a similarity in their evolution. If the values of (O/H)_0 and (O/H)_R25 in the galaxy were close to that of the Milky Way, then the galaxy was referred to as an evolutionary Milky Way analogue (eMWA). If the galaxy was simultaneously an eMWA and sMWA, then the galaxy was considered a Milky Way twin. We find that the position of the Milky Way on the (O/H)_0 - (O/H)_R25 diagram shows a large deviation from the general trend in the sense that the (O/H)_R25 in the Milky Way is appreciably lower than in other galaxies of similar (O/H)_0. This feature of the Milky Way evidences that its (chemical) evolution is not typical. We identify four galaxies (NGC~3521, NGC~4651, NGC~2903, and MaNGA galaxy M-8341-09101) that are simultaneously sMWA and eMWA and can therefore be considered as Milky Way twins. In previous studies, Milky Way-like galaxies were selected using structural and morphological characteristics, that is, sMWAs were selected. We find that the abundances at the centre and at the optical radius (evolutionary characteristics) provide a stricter criterion for selecting real Milky Way twins

4.Cosmic ray processes in galactic ecosystems

Authors:Ellis R. Owen, Kinwah Wu, Yoshiyuki Inoue, H. -Y. Karen Yang, Alison M. W. Mitchell

Abstract: Galaxy evolution is an important topic, and our physical understanding must be complete to establish a correct picture. This includes a thorough treatment of feedback. The effects of thermal-mechanical and radiative feedback have been widely considered, however cosmic rays (CRs) are also powerful energy carriers in galactic ecosystems. Resolving the capability of CRs to operate as a feedback agent is therefore essential to advance our understanding of the processes regulating galaxies. The effects of CRs are yet to be fully understood, and their complex multi-channel feedback mechanisms operating across the hierarchy of galaxy structures pose a significant technical challenge. This review examines the role of CRs in galaxies, from the scale of molecular clouds to the circum-galactic medium. An overview of their interaction processes, their implications for galaxy evolution, and their observable signatures is provided and their capability to modify the thermal and hydrodynamic configuration of galactic ecosystems is discussed. We present recent advancements in our understanding of CR processes and interpretation of their signatures, and highlight where technical challenges and unresolved questions persist. We discuss how these may be addressed with upcoming opportunities.

5.Nature of Striation in 21 cm Channel Maps: Velocity Caustics

Authors:Yue Hu, A. Lazarian, D. Alina, D. Pogosyan, Ka Wai Ho

Abstract: The alignment of striated intensity structures in thin neutral hydrogen (HI) spectroscopic channels with Galactic magnetic fields has been observed. However, the origin and nature of these striations are still debatable. Some studies suggest that the striations result solely from real cold-density filaments without considering the role of turbulent velocity fields, i.e., the velocity caustics effect in shaping the channel's intensity distribution. To determine the relative contribution of density and velocity in forming the striations in channel maps, we analyze synthetic observations of channel maps obtained with simulations that represent realistic magnetized multi-phase HI. We vary the thickness of the channel maps and apply the Velocity Decomposition Algorithm to separate the velocity and density contributions. In parallel, we analyze GALFA HI observations and compare the results. Our analysis shows that the thin channels are dominated by velocity contribution, and velocity caustics mainly generate the HI striations. We show that velocity caustics can cause a correlation between unsharp-masked HI structures and far-infrared emission. We demonstrate that the linear HI fibers revealed by the Rolling Hough Transform (RHT) in thin velocity channels originate from velocity caustics. As the thickness of channel maps increases, the relative contribution of density to fluctuations in channel maps also increases. As a result, more RHT-detected fibers tend to be perpendicular to the magnetic field. Conversely, the alignment with the magnetic field is the most prominent in thin channels. We conclude that similar to the Velocity Channel Gradients (VChGs) approach, RHT traces magnetic fields through the analysis of velocity caustics in thin channel maps.

6.Damping of MHD Turbulence in A Partially Ionized Medium

Authors:Yue Hu, Siyao Xu, Lev Arzamasskiy, James M. Stone, A. Lazarian

Abstract: Ions and neutrals in the interstellar medium play a key role in the dynamics of magnetohydrodynamic (MHD) turbulence, but challenging to study. In this study, we investigate the damping of MHD turbulence using 3D two-fluid simulations generated with the AthenaK code. Specifically, we examine the density, velocity, and magnetic field statistics of the two-fluid turbulence. Our results demonstrate that when ions and neutrals are strongly coupled, the velocity statistics resemble those of single-fluid MHD turbulence. However, when neutrals begin to decouple from ions, turbulence in both neutrals and ions is damped, resulting in steep kinetic energy spectra compared to Kolmogorov-type turbulence. We attribute the damping of turbulence in neutrals to their local coupling with ions, caused by local variations in the ionization fraction and Alfv\'en speed. The neutral-ion decoupling scale is not fixed but extends to a range of values. After neutrals completely decouple from ions, the neutrals have a Kolmogorov-type kinetic energy spectrum, while the ions' spectrum remains steep. We find that ion and neutral densities can be different when their coupling is weak but velocity statistics remain similar, indicating that densities are more sensitive to neutral-ion decoupling than velocities. The density structures of ions are filamentary, while those of neutrals are clumpy. Using the probability distribution function of logarithmic mass density, we find density fluctuations in ions can be enhanced when neutral and ions are weakly coupled. We confirm that the magnetic field spectrum can be steep due to the damping of MHD turbulence by neutral-ion collision.

1.The Spectacular Tidal Tails of Globular Cluster M3 (NGC 5272)

Authors:Yong Yang NAOC UCAS, Jing-Kun Zhao NAOC, Xin-Zhe Tang, Xian-Hao Ye, Gang Zhao

Abstract: We provide a detailed analysis on tidal tails of the globular cluster M3 (NGC 5272). We first discover clear extra-tidal structures with slight S-shape near the cluster. This inspires us to examine the existence of its long tidal tails. We highlight potential stream stars using proper motions (PMs) of a model stream combined with the cluster's locus in a color-magnitude diagram (CMD). A 35 deg long leading tail and a 21 deg long trailing tail are successfully detected at the same time. Their corresponding overdensities can be recognized in CMD and PM space after subtracting background. We estimate stream width, star number density and surface brightness for both tails, as well as the distance variation along the entire stream. We then verify the connection of M3 and the Sv\"{o}l stream. Finally, we tabulate 11 member stars belonging to the M3 tidal stream with available spectroscopic observations.

2.Exploring Stellar Cluster and Feedback-driven Star Formation in Galactic Mid-infrared Bubble [HKS2019] E70

Authors:Aayushi Verma, Saurabh Sharma, Kshitiz K. Mallick, Lokesh Dewangan, Devendra K. Ojha, Ram Kesh Yadav, Rakesh Pandey, Arpan Ghosh, Harmeen Kaur, Neelam Panwar, Tarak Chand

Abstract: We present a comprehensive analysis of the Galactic mid-infrared (MIR) bubble [HKS2019] E70 (E70) by adopting a multi-wavelength approach to understand the physical environment and star formation scenario around it. We identified a small (radius ~1.7 pc) stellar clustering inside the E70 bubble and its distance is estimated as 3.26 +/- 0.45 kpc. This cluster is embedded in the molecular cloud and hosts massive stars as well as young stellar objects (YSOs), suggesting active star formation in the region. The spectral type of the brightest star 'M1' of the E70 cluster is estimated as O9V and a circular ring/shell of gas and dust is found around it. The diffuse radio emission inside this ring/shell, the excess pressure exerted by the massive star 'M1' at the YSOs core, and the distribution of photo-dissociation regions (PDRs), a Class I YSO, and two ultra-compact (UC) H II regions on the rim of this ring/shell, clearly suggest positive feedback of the massive star 'M1' in the region. We also found a low-density shell-like structure in 12 CO(J=1-0) molecular emission along the perimeter of the E70 bubble. The velocity structure of the 12 CO emission suggests that the feedback from the massive star appears to have expelled the molecular material and subsequent swept-up material is what appears as the E70 bubble.

3.An overview of desorption parameters of Volatile and Complex Organic Molecules: A systematic dig on experimental literature

Authors:N. F. W. Ligterink, M. Minissale

Abstract: Many molecules observed in the interstellar medium are thought to result from thermal desorption of ices. Parameters such as desorption energy and pre-exponential frequency factor are essential to describe the desorption of molecules. Experimental determinations of these parameters are missing for many molecules, including those found in the interstellar medium. The objective of this work is to expand the number of molecules for which desorption parameters are available, by collecting and re-analysing experimental temperature programmed desorption data that are present in the literature. Transition State Theory (TST) is used in combination with the Redhead equation to determine desorption parameters. Experimental data and molecular constants (e.g., mass, moment of inertia) are collected and given as input. Using the Redhead-TST method, the desorption parameters for 133 molecules have been determined. The Redhead-TST method is found to provide reliable results that agree well with desorption parameters determined with more rigorous experimental methods. The importance of using accurately determined pre-exponential frequency factors to simulate desorption profiles is emphasised. The large amount of data allows to look for trends, the most important is the relationship log$_{10}$($\nu$) = 2.65ln($m$) + 8.07, where $\nu$ is the pre-exponential frequency factor and $m$ the mass of the molecule. The data collected in this work allow to model the thermal desorption of molecules and help understand changes in chemical and elemental composition of interstellar environments.

4.New Dimensions of Galactic Chemical Evolution

Authors:David H. Weinberg

Abstract: Dramatic recent progress in understanding galactic chemical evolution (GCE) has been driven partly by direct observations of the distant past with HST and JWST of stellar abundances from giant high-resolution spectroscopic surveys (APOGEE, GALAH) and the complementary power of Gaia astrometry and photometry. Focusing on archaeology, I give a rapid-fire, and I hope synthesizing, review of work my collaborators and I have done on theoretical modeling and observational interpretation. I discuss (1) the interleaved but distinguishable roles of stellar scale astrophysics and galactic scale astrophysics in governing GCE, (2) the use of abundance ratio trends to empirically infer nucleosynthetic yields, (3) the uncertainty in the overall scale of yields and its degeneracy with the importance of galactic outflows, (4) the emergence of equilibrium in GCE, (5) the dimensionality of the stellar distribution in chemical abundance space, and (6) insights from chemical abundances on the early history of the Milky Way, including measurements of the intrinsic scatter of abundance ratios in metal-poor stars (-2 < [Fe/H] < -1), suggesting that a typical halo star at this metallicity is enriched by the products of $N \sim 50$ supernovae mixed over $\sim 10^5 M_\odot$ of star-forming gas.

5.GN-z11: The environment of an AGN at $z=$10.603

Authors:Jan Scholtz, Callum Witten, Nicolas Laporte, Hannah Ubler, Michele Perna, Roberto Maiolino, Santiago Arribas, William Baker, Jake Bennett, Francesco D'Eugenio, Sandro Tacchella, Joris Witstok, Andrew Bunker, Stefano Carniani, Stephane Charlot, Emma Curtis-Lake, Daniel Eisenstein, Brant Robertson, Bruno Rodriguez Del Pino, Charlotte Simmonds, Renske Smit, Giacomo Venturi, Christina Williams, Christopher Willmer

Abstract: Recent observations with the \textit{James Webb} Space Telescope (JWST) have further refined the spectroscopic redshift of GN-z11, one of the most distant galaxies identified with the \textit{Hubble} Space Telescope (HST) at $z=10.603$. The presence of extremely dense gas ($>10^{10}$ cm$^{-3}$), the detection of high-ionisation lines and of CII*1335 emission, as well as the presence of an ionisation cone, indicate that GN-z11 also hosts an Active Galactic Nucleus (AGN). Further photometric and spectroscopic follow-up demonstrates that it lies in a large-scale, overdense structure with possible signatures of Population III (PopIII) stars in its halo. Surprisingly, Ly$\alpha$ has also been detected despite the expected largely neutral inter-galactic medium at such a redshift. We exploit recent JWST/NIRSpec IFU observations to demonstrate that the Ly$\alpha$ emission in GN-z11 is part of an extended halo with a minimum size of 0.8--3.2 kpc, depending on the definition used to derive the halo size. The surface brightness of the Ly$\alpha$ halo around GN-z11 appears consistent with Ly$\alpha$ halos observed around $z\sim6$ quasars. At the wavelength of Ly$\alpha$ at $z\sim$10.6, we identify three other emission line candidates within the IFU Field-of-View with no UV rest-frame counterpart visible in deep images from the JWST/NIRCam. If confirmed, this could be the first evidence that the local region of GN-z11 represents a candidate protocluster core, forming just 400 Myr after the Big Bang. We give a first estimate of the dark matter halo mass of this structure ($M_h$=2.96$^{+0.44}_{-0.39} \times$10$^{10}$ M$_{\odot}$), consistent with a Coma-like cluster progenitor.

6.Decoding the age-chemical structure of the Milky Way disk: An application of Copulas and Elicitable Maps

Authors:Aarya A. Patil, Jo Bovy, Sebastian Jaimungal, Neige Frankel, Henry W. Leung

Abstract: In the Milky Way, the distribution of stars in the $[\alpha/\mathrm{Fe}]$ vs. $[\mathrm{Fe/H}]$ and $[\mathrm{Fe/H}]$ vs. age planes holds essential information about the history of star formation, accretion, and dynamical evolution of the Galactic disk. We investigate these planes by applying novel statistical methods called copulas and elicitable maps to the ages and abundances of red giants in the APOGEE survey. We find that the low- and high-$\alpha$ disk stars have a clean separation in copula space and use this to provide an automated separation of the $\alpha$ sequences using a purely statistical approach. This separation reveals that the high-$\alpha$ disk ends at the same [$\alpha$/Fe] and age at high $[\mathrm{Fe/H}]$ as the low-$[\mathrm{Fe/H}]$ start of the low-$\alpha$ disk, thus supporting a sequential formation scenario for the high- and low-$\alpha$ disks. We then combine copulas with elicitable maps to precisely obtain the correlation between stellar age $\tau$ and metallicity $[\mathrm{Fe/H}]$ conditional on Galactocentric radius $R$ and height $z$ in the range $0 < R < 20$ kpc and $|z| < 2$ kpc. The resulting trends in the age-metallicity correlation with radius, height, and [$\alpha$/Fe] demonstrate a $\approx 0$ correlation wherever kinematically-cold orbits dominate, while the naively-expected negative correlation is present where kinematically-hot orbits dominate. This is consistent with the effects of spiral-driven radial migration, which must be strong enough to completely flatten the age-metallicity structure of the low-$\alpha$ disk.

1.The EDGE-CALIFA Survey: Spatially Resolved 13CO(1-0) Observations and Variations in 12CO(1-0)/13CO(1-0) in Nearby Galaxies on kpc Scales

Authors:Yixian Cao, Tony Wong, Alberto D. Bolatto, Adam Leroy, Erik W. Rosolowsky, Dyas Utomo, Sebastian Sanchez, Jorge Barrera-Ballesteros, Rebecca Levy, Dario Colombo, Leo Blitz, Stuart Vogel, Johannes Puschnig, Vicente Villanueva, Monica Rubio

Abstract: We present 13CO(1-0) observations for the EDGE-CALIFA survey, which is a mapping survey of 126 nearby galaxies at a typical spatial resolution of 1.5 kpc. Using detected 12CO(1-0) emission as a prior, we detect 13CO(1-0) in 41 galaxies via integrated line flux over the entire galaxy, and in 30 galaxies via integrated line intensity in resolved synthesized beams. Incorporating our CO observations and optical IFU spectroscopy, we perform a systematic comparison between the line ratio R12/13 and the properties of the stars and ionized gas. Higher R12/13 values are found in interacting galaxies than in non-interacting galaxies. The global R12/13 slightly increases with infrared color F60/F100, but appears insensitive to other host galaxy properties such as morphology, stellar mass, or galaxy size. We also present annulus-averaged R12/13 profiles for our sample up to a galactocentric radius of 0.4r25 (~6 kpc), taking into account the 13CO(1-0) non-detections by spectral stacking. The radial profiles of R12/13 are quite flat across our sample. Within galactocentric distances of 0.2r25, azimuthally-averaged R12/13 increases with star formation rate. However, the Spearman rank correlation tests show the azimuthally-averaged R12/13 does not strongly correlate with any other gas or stellar properties in general, especially beyond 0.2r25 from the galaxy centers. Our findings suggest that in the complex environments in galaxy disks, R12/13 is not a sensitive tracer for ISM properties. Dynamical disturbances, like galaxy interactions or the presence of a bar, also have an overall impact on R12/13, which further complicate the interpretations of R12/13 variations.

2.Multi-Epoch Machine Learning 2: Identifying physical drivers of galaxy properties in simulations

Authors:Robert McGibbon, Sadegh Khochfar

Abstract: Using a novel machine learning method, we investigate the buildup of galaxy properties in different simulations, and in various environments within a single simulation. The aim of this work is to show the power of this approach at identifying the physical drivers of galaxy properties within simulations. We compare how the stellar mass is dependent on the value of other galaxy and halo properties at different points in time by examining the feature importance values of a machine learning model. By training the model on IllustrisTNG we show that stars are produced at earlier times in higher density regions of the universe than they are in low density regions. We also apply the technique to the Illustris, EAGLE, and CAMELS simulations. We find that stellar mass is built up in a similar way in EAGLE and IllustrisTNG, but significantly differently in the original Illustris, suggesting that subgrid model physics is more important than the choice of hydrodynamics method. These differences are driven by the efficiency of supernova feedback. Applying principal component analysis to the CAMELS simulations allows us to identify a component associated with the importance of a halo's gravitational potential and another component representing the time at which galaxies form. We discover that the speed of galactic winds is a more critical subgrid parameter than the total energy per unit star formation. Finally we find that the Simba black hole feedback model has a larger effect on galaxy formation than the IllustrisTNG black hole feedback model.

3.Impact of Dynamical Friction on the Tidal Formation of NGC 1052-DF2

Authors:Ryosuke Katayama, Kentaro Nagamine

Abstract: If a normal dwarf satellite galaxy repeatedly suffers from strong tidal forces while orbiting a massive halo, it can turn into a dark matter-deficient galaxy (DMDG). It has been shown that NGC 1052-DF2 can form due to this tidal scenario by N-body simulation; however, the dynamical friction has been ignored in the literature. We perform a self-consistent full N-body simulation to investigate the effect of dynamical friction on the formation scenario and compare it with the one without dynamical friction. We find that dynamical friction causes a dramatic decay of the satellite's orbit. This makes the orbital period shorter, and the mass of the satellite decreases more rapidly. As a result, the satellite galaxy suffering from dynamical friction becomes a DMDG in $\approx 7-8$ Gyr, which is $\approx 2-3$ Gyr earlier than that in the simulation without dynamical friction. Although the distribution of the globular clusters (GCs) in our simulation does not fully agree with that of DF2, the current observations still have large uncertainties. Our result implies that DF2 can be formed by a more circular orbit within a Hubble time, and that DMDGs can be formed by this tidal scenario more often than previously thought.

4.ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): A forming quadruple system with continuum `ribbons' and intricate outflows

Authors:Qiu-yi Luo, Tie Liu, Aaron T. Lee, Stella S. R. Offner, James di Francesco, Doug Johnstone, Mika Juvela, Paul F. Goldsmith, Sheng-Li Qin, Xiaofeng Mai, Xun-chuan Liu, Patricio Sanhueza, Feng-Wei Xu, Ken'ichi Tatematsu, Somnath Dutta, Huei-Ru Vivien Chen, Shanghuo Li, Aiyuan Yang, Sheng-Yuan Liu, Chin-Fei Lee, Naomi Hirano, Chang Won Lee, Dipen Sahu, Hsien Shang, Shih-Ying Hsu, Leonardo Bronfman, Woojin Kwon, M. G. Rawlings, David Eden, Xing Lu, Qi-lao Gu, Zhiyuan Ren, D Ward-Thompson, Zhi-Qiang Shen

Abstract: One of the most poorly understood aspects of low-mass star formation is how multiple-star systems are formed. Here we present the results of Atacama Large Millimeter/submillimeter Array (ALMA) Band-6 observations towards a forming quadruple protostellar system, G206.93-16.61E2, in the Orion B molecular cloud. ALMA 1.3 mm continuum emission reveals four compact objects, of which two are Class I young stellar objects (YSOs), and the other two are likely in prestellar phase. The 1.3 mm continuum emission also shows three asymmetric ribbon-like structures that are connected to the four objects, with lengths ranging from $\sim$500 au to $\sim$2200 au. By comparing our data with magneto-hydrodynamic (MHD) simulations, we suggest that these ribbons trace accretion flows and also function as gas bridges connecting the member protostars. Additionally, ALMA CO J=2-1 line emission reveals a complicated molecular outflow associated with G206.93-16.61E2 with arc-like structures suggestive of an outflow cavity viewed pole-on.

5.Statistics for Galaxy Outflows at $z\sim 6-9$ with Imaging and Spectroscopic Signatures Identified with JWST/NIRCam and NIRSpec Data

Authors:Yechi Zhang, Masami Ouchi, Kimihiko Nakajima, Yuichi Harikane, Yuki Isobe, Yi Xu, Yoshiaki Ono, Hiroya Umeda

Abstract: We present statistics of $z\sim 6-9$ galaxy outflows indicated by spatially-extended gas emission and broad lines. With a total of 61 spectroscopically confirmed galaxies at $z\sim 6-9$ in the JWST CEERS, GLASS, and ERO data, we find five galaxies with [O{\sc iii}]+H$\beta$ ionized gas emission significantly extended beyond the kpc-scale stellar components on the basis of the emission line images constructed by the subtraction of NIRCam broadband (line on/off-band) images. By comparison with low-$z$ galaxies, the fraction of galaxies with the spatially extended gas, 5/61, at $z\sim 6-9$ is an order of magnitude higher than those at $z\sim 0-1$, which can be explained by events triggered by frequent major mergers at high redshift. We also investigate medium- and high-resolution NIRSpec spectra of 30 galaxies at $z\sim 6-9$, and identify five galaxies with broad ($140-800$~km~s$^{-1}$) lines in the [O{\sc iii}] forbidden line emission, suggestive of galaxy outflows. One galaxy at $z=6.38$ shows both the spatially-extended gas emission and the broad lines, while none of the galaxies with the spatially-extended gas emission or broad lines present a clear signature of AGN either in the line diagnostics or Type 1 AGN line broadening ($>1000$~km~s$^{-1}$), which hint outflows mainly driven by stellar feedback. The existence of galaxies with/without spatially-extended gas emission or broad lines may suggest that these are galaxies in the early, late, post phases of galaxy outflows at high redshift, where the relatively large fractions of such galaxies indicate the longer-duration and/or more-frequent outflows at the early cosmic epoch.

1.On the origin of the anomalous gas, non-declining rotation curve and disc asymmetries in NGC253

Authors:Xuanyi Lyu, T. Westmeier, Gerhardt R. Meurer, D. J. Hanish

Abstract: We present a multi-wavelength (from far ultraviolet to HI emission) study of star formation feedback on the kinematics of the interstellar medium in the Sculptor Galaxy, NGC253. Its three well-known features (a disrupted stellar disc, a previously reported delining rotation curve, and anomalous HI gas) are studied in a common context of disc asymmetries. About 170 h of on-source ATCA observations are collected and reduced into two versions of \HI\ data cubes of different angular resolution (30'' / 2') and HI column density sensitivity (7.4 $\times$ $10^{19}$cm$^{-2}$ / 4$\times$ $10^{18}$cm$^{-2}$). We separate the anomalous gas from the disc using a custom-made line profile fitting toolkit called FMG. Two star formation tracers (H$\alpha$, FUV emission) are carefully processed and studied. We find that at $R > 7.5~\mathrm{kpc}$ the star formation activity is strongly lopsided (SFR$_{NE}$ >SFR$_{SW}$), and investigate several other properties (H$\alpha$/FUV, dust temperature, stellar age, and disc stability parameters). We also find that the declining nature of the rotation curve perceived by previous studies is not intrinsic but a combined effect of kinematical asymmetries at $R = 7.5$--$16~\mathrm{kpc}$. This is likely the consequence of star formation triggered outflow. The mass distribution and the timescale of the anomalous gas also imply that it originates from gas outflow, which is perhaps caused by galaxy-galaxy interaction considering the crowded environment of NGC253.

2.A Decade of Near-Infrared Variability in NGC4388: Insights into the AGN Structure

Authors:Luis G. Dahmer-Hahn, Alberto Rodríguez-Ardila, Marina Bianchin, Rogemar A. Riffel, Rogério Riffel, Thaisa Storchi-Bergmann, Lei Hao

Abstract: Variability studies have proven to be a powerful diagnostic tool for understanding the physics and properties of of Active Galactic Nuclei (AGNs). They provide insights into the spatial and temporal distribution of the emitting regions, the structure and dynamics of the accretion disk, and the properties of the central black hole. Here, we have analysed the K-band spectral variability of the Seyfert 1.9/2 galaxy NGC4388 spanning five epochs over a period of ten years. We have performed spectral synthesis of the nuclear region and found that the contribution of warm dust (T~800K) declined by 88% during these 10 years. In the same period, the [CaVIII] coronal line decreased 61%, whereas BrG emission declined 35%. For the HeI and H2, we did not detect any significant variation beyond their uncertainties. Based on the time span of these changes, we estimate that the region where the warm dust is produced is smaller than 0.6pc, which suggests that this spectral feature comes from the innermost part of the region sampled, directly from the AGN torus. On the other hand, the bulk of [CaVIII] is produced in the inner ~2pc and the nuclear BrG region is more extended, spanning a region larger than 3pc. Lastly, HeI and H2 are even more external, with most of the emission probably being produced in the host galaxy rather than in the AGN. This is the first spectroscopic variability study in the NIR for an AGN where the central source is not directly visible.

3.A CO Funnel in the Galactic Centre: Molecular Counterpart of the Northern Galactic Chimney?

Authors:V. S. Veena, D. Riquelme, W. -J. Kim, K. M. Menten, P. Schilke, M. C. Sormani, W. E. Banda-Barragan, F. Wyrowski, G. A. Fuller, A. Cheema

Abstract: We report the discovery of a velocity coherent, funnel shaped ^13CO emission feature in the Galactic centre (GC) using data from the SEDIGISM survey. The molecular cloud appears as a low velocity structure (V_LSR=[-3.5, +3.5] km/s) with an angular extent of 0.95{\deg} x 1{\deg}, extending toward positive Galactic latitudes. The structure is offset from Sgr A* toward negative Galactic longitudes and spatially and morphologically correlates well with the northern lobe of the 430 pc radio bubble, believed to be the radio counterpart of the multiwavelength GC chimney. Spectral line observations in the frequency range of 85-116 GHz have been carried out using the IRAM 30 metre telescope toward 12 positions along the funnel-shaped emission. We examine the ^12C/^13C isotopic ratios using various molecules and their isotopologues. The mean ^12C/^13C isotope ratio (30.6+-2.9) is consistent with the structure located within inner 3 kpc of the Galaxy and possibly in the GC. The velocity of the molecular funnel is consistent with previous radio recombination line measurements of the northern lobe of radio bubble. Our multiwavelength analysis suggests that the funnel shaped structure extending over 100 pc above the Galactic plane is the molecular counterpart of the northern GC chimney.

4.Interstellar Polarization Survey III: Relation Between Optical Polarization and Reddening in the General Interstellar Medium

Authors:Y. Angarita, M. J. F. Versteeg, M. Haverkorn, C.