Reassessing the ZTF Volume-Limited Type Ia Supernova Sample and Its Implications for Continuous, Dust-Dependent Models of Intrinsic Scatter

Reassessing the ZTF Volume-Limited Type Ia Supernova Sample and Its Implications for Continuous, Dust-Dependent Models of Intrinsic Scatter

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By: Yukei S. Murakami, Daniel Scolnic

The ZTF DR2 includes light curves of 3628 Type Ia supernovae (SNe Ia), making it the largest low-redshift SNe Ia sample available. One central question for analyses of SNe Ia is whether the remaining diversity of standardized luminosities arises in part from an intrinsic or extrinsic effect; characterized by the color-independent bimodality in progenitor population or color- and host- dependent diversity in dust extinction, respectively. In t... more
The ZTF DR2 includes light curves of 3628 Type Ia supernovae (SNe Ia), making it the largest low-redshift SNe Ia sample available. One central question for analyses of SNe Ia is whether the remaining diversity of standardized luminosities arises in part from an intrinsic or extrinsic effect; characterized by the color-independent bimodality in progenitor population or color- and host- dependent diversity in dust extinction, respectively. In the initial analyses of the volume-limited subset (z < 0.06; 945 SNe) of this sample from the ZTF collaboration, the authors reported evidences for the former hypothesis, in contrast to many of the previous evidences for the dust hypothesis found across other largest high- and low- redshift SNe Ia samples. We re-analyze the volume-limited ZTF SNe Ia in the same manner that previous samples were analyzed and report consistency with trends seen in literature samples and in support of the dust hypothesis. We find the following: 1. a color dependency in the canonical `mass-step' size for SNe, with red SNe having a larger host-dependent residual step than blue SNe by 0.18 $\pm$ 0.09 mag; 2. a color-dependent difference in the Hubble residual scatter, with red SNe having a $\sim$ 33% larger scatter than blue SNe at > 3$\sigma$ significance; 3. data's preference of a model that accounts for color-dependency over a simple `step' model at $\sim$ 3$\sigma$; 4. the strongest evidence to date (3.5$\sigma$) that the relationship between SN color, host-galaxy properties, and luminosity is continuous rather than characterized by a discrete step. Accounting for 3 and 4 with our new model, Host2D, yields a 4.0$\sigma$ improvement over the mass-step model. We trace the difference in reported findings to the fitting and analysis methods, in particular the model complexity allowed for the color-luminosity relation, rather than a difference in the sample itself. less
Cosmology and Nongalactic Astrophysics
Radial Profiles of Radio Halos in Massive Galaxy Clusters: Diffuse Giants Over 2 Mpc

Radial Profiles of Radio Halos in Massive Galaxy Clusters: Diffuse Giants Over 2 Mpc

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By: K. Rajpurohit, A. Botteon, E. O'Sullivan, W. Forman, M. Balboni, L. Bruno, R. J. van Weeren, M. Hoeft, G. Brunetti, C. Jones, A. S. Rajpurohit, S. P. Sikhosana

We present new, high frequency radio observations of the merging galaxy clusters PLCK G287.0+32.9, Abell 2744, and Bullet. These clusters are known to host $\sim$Mpc scale sources, known as radio halos, which are formed by the acceleration of cosmic rays by turbulence injected into the intracluster medium during cluster mergers. Our new images reveal previously undetected faint outermost regions of halos, extending to over 2 Mpc. This discove... more
We present new, high frequency radio observations of the merging galaxy clusters PLCK G287.0+32.9, Abell 2744, and Bullet. These clusters are known to host $\sim$Mpc scale sources, known as radio halos, which are formed by the acceleration of cosmic rays by turbulence injected into the intracluster medium during cluster mergers. Our new images reveal previously undetected faint outermost regions of halos, extending to over 2 Mpc. This discovery highlights the presence of radio halos with large extents at high frequencies and suggests that their observable size depends on a combination of the observation sensitivity and uv-coverage, and their radio power. We additionally compare the properties of these three clusters with MACS J0717+3745 and Abell 2142, both of which are known to host prominent large radio halos. Remarkably, all five halos, despite their exceptionally large extents, exhibit properties similar to other classical halos: their radial profiles are described by a single-component exponential fit, they show radial spectral index steepening, and have an average radio emissivity of about $10^{-42}\, \mathrm{erg\,s^{-1}\,cm^{-3}\,Hz^{-1}}$. Our results demonstrate that radio halos can extend to the cluster periphery, without the transition to an observationally distinguishable different halo component in the outermost regions. Our findings highlight that careful subtraction of unrelated sources embedded in the halo is necessary to measure the radio surface brightness accurately, as incomplete subtraction can introduce an apparent secondary component in the peripheral regions. less
Cosmology and Nongalactic Astrophysics
Redshift Drift in Relativistic N-Body Simulations

Redshift Drift in Relativistic N-Body Simulations

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By: Alexander Oestreicher, Chris Clarkson, Julian Adamek, Sofie Marie Koksbang

The cosmological redshift drift promises to be the first observable directly measuring the cosmic expansion rate and should be detectable with upcoming surveys by the Square Kilometre Array and the Extremely Large Telescope. To prepare for these upcoming measurements we study the redshift drift in detail using the relativistic N-body code $\texttt{gevolution}$ focusing on inhomogeneity-induced fluctuations. Using a ray-tracer, we calculate th... more
The cosmological redshift drift promises to be the first observable directly measuring the cosmic expansion rate and should be detectable with upcoming surveys by the Square Kilometre Array and the Extremely Large Telescope. To prepare for these upcoming measurements we study the redshift drift in detail using the relativistic N-body code $\texttt{gevolution}$ focusing on inhomogeneity-induced fluctuations. Using a ray-tracer, we calculate the redshift drift directly from the light cone at two different time steps. To investigate observer-dependent biases we consider 10 different observers. We find that inhomogeneity-induced fluctuations in the redshift drift can in extreme cases be of the same order as the cosmic signal for $z\lesssim0.15$. By comparing our results to first-order perturbation theory, we find that the extreme outliers are due to peculiar motion in over-densities and can be described by first-order perturbation theory to percent precision. We calculate angular power spectra that fit very well with our theoretical predictions based on perturbation theory at linear scales and show a surprisingly large non-linear signal. This shows that redshift drift not only has the power to measure the background expansion, but could also deliver information about the velocity and acceleration fields in clusters. less
Cosmology and Nongalactic Astrophysics
Euclid preparation. The impact of redshift interlopers on the two-point correlation function analysis

Euclid preparation. The impact of redshift interlopers on the two-point correlation function analysis

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By: Euclid Collaboration, I. Risso, A. Veropalumbo, E. Branchini, E. Maragliano, S. de la Torre, E. Sarpa, P. Monaco, B. R. Granett, S. Lee, G. E. Addison, S. Bruton, C. Carbone, G. Lavaux, K. Markovic, K. McCarthy, G. Parimbelli, F. Passalacqua, W. J. Percival, C. Scarlata, E. Sefusatti, Y. Wang, M. Bonici, F. Oppizzi, N. Aghanim, B. Altieri, A. Amara, S. Andreon, N. Auricchio, C. Baccigalupi, M. Baldi, A. Balestra, S. Bardelli, P. Battaglia, A. Biviano, A. Bonchi, D. Bonino, M. Brescia, J. Brinchmann, S. Camera, G. Cañas-Herrera, V. Capobianco, V. F. Cardone, J. Carretero, S. Casas, M. Castellano, G. Castignani, S. Cavuoti, K. C. Chambers, A. Cimatti, C. Colodro-Conde, G. Congedo, C. J. Conselice, L. Conversi, Y. Copin, F. Courbin, H. M. Courtois, M. Crocce, A. Da Silva, H. Degaudenzi, G. De Lucia, A. M. Di Giorgio, H. Dole, M. Douspis, F. Dubath, C. A. J. Duncan, X. Dupac, S. Dusini, S. Escoffier, M. Farina, R. Farinelli, F. Faustini, S. Ferriol, F. Finelli, S. Fotopoulou, N. Fourmanoit, M. Frailis, E. Franceschi, M. Fumana, S. Galeotta, K. George, W. Gillard, B. Gillis, C. Giocoli, J. Gracia-Carpio, A. Grazian, F. Grupp, L. Guzzo, S. V. H. Haugan, W. Holmes, F. Hormuth, A. Hornstrup, P. Hudelot, K. Jahnke, M. Jhabvala, B. Joachimi, E. Keihänen, S. Kermiche, A. Kiessling, M. Kilbinger, B. Kubik, M. Kümmel, M. Kunz, H. Kurki-Suonio, A. M. C. Le Brun, P. Liebing, S. Ligori, P. B. Lilje, V. Lindholm, I. Lloro, G. Mainetti, D. Maino, E. Maiorano, O. Mansutti, S. Marcin, O. Marggraf, M. Martinelli, N. Martinet, F. Marulli, R. Massey, S. Maurogordato, E. Medinaceli, S. Mei, M. Melchior, Y. Mellier, M. Meneghetti, E. Merlin, G. Meylan, A. Mora, M. Moresco, L. Moscardini, R. Nakajima, C. Neissner, S. -M. Niemi, J. W. Nightingale, C. Padilla, S. Paltani, F. Pasian, K. Pedersen, V. Pettorino, S. Pires, G. Polenta, M. Poncet, L. A. Popa, L. Pozzetti, F. Raison, R. Rebolo, A. Renzi, J. Rhodes, G. Riccio, E. Romelli, M. Roncarelli, E. Rossetti, R. Saglia, Z. Sakr, D. Sapone, B. Sartoris, J. A. Schewtschenko, P. Schneider, T. Schrabback, M. Scodeggio, A. Secroun, G. Seidel, M. Seiffert, S. Serrano, P. Simon, C. Sirignano, G. Sirri, L. Stanco, J. Steinwagner, C. Surace, P. Tallada-Crespí, D. Tavagnacco, A. N. Taylor, I. Tereno, N. Tessore, S. Toft, R. Toledo-Moreo, F. Torradeflot, I. Tutusaus, L. Valenziano, J. Valiviita, T. Vassallo, G. Verdoes Kleijn, D. Vibert, J. Weller, G. Zamorani, F. M. Zerbi, E. Zucca, V. Allevato, M. Ballardini, M. Bolzonella, E. Bozzo, C. Burigana, R. Cabanac, A. Cappi, D. Di Ferdinando, J. A. Escartin Vigo, L. Gabarra, W. G. Hartley, J. Martín-Fleitas, S. Matthew, N. Mauri, R. B. Metcalf, A. Pezzotta, M. Pöntinen, C. Porciani, V. Scottez, M. Sereno, M. Tenti, M. Viel, M. Wiesmann, Y. Akrami, S. Alvi, I. T. Andika, M. Archidiacono, F. Atrio-Barandela, S. Avila, A. Balaguera-Antolinez, C. Benoist, D. Bertacca, M. Bethermin, L. Blot, H. Böhringer, S. Borgani, M. L. Brown, A. Calabro, B. Camacho Quevedo, F. Caro, C. S. Carvalho, T. Castro, F. Cogato, A. R. Cooray, O. Cucciati, S. Davini, F. De Paolis, G. Desprez, A. Díaz-Sánchez, J. J. Diaz, S. Di Domizio, J. M. Diego, P. Dimauro, A. Enia, Y. Fang, A. G. Ferrari, A. Finoguenov, A. Fontana, A. Franco, K. Ganga, J. García-Bellido, T. Gasparetto, V. Gautard, E. Gaztanaga, F. Giacomini, F. Gianotti, G. Gozaliasl, M. Guidi, C. M. Gutierrez, A. Hall, S. Hemmati, C. Hernández-Monteagudo, H. Hildebrandt, J. Hjorth, S. Joudaki, J. J. E. Kajava, Y. Kang, V. Kansal, D. Karagiannis, K. Kiiveri, C. C. Kirkpatrick, S. Kruk, V. Le Brun, J. Le Graet, L. Legrand, M. Lembo, F. Lepori, G. Leroy, G. F. Lesci, L. Leuzzi, T. I. Liaudat, A. Loureiro, J. Macias-Perez, M. Magliocchetti, F. Mannucci, R. Maoli, C. J. A. P. Martins, L. Maurin, M. Miluzio, C. Moretti, G. Morgante, S. Nadathur, K. Naidoo, A. Navarro-Alsina, K. Paterson, L. Patrizii, A. Pisani, D. Potter, S. Quai, M. Radovich, P. -F. Rocci, S. Sacquegna, M. Sahlén, D. B. Sanders, A. Schneider, D. Sciotti, E. Sellentin, L. C. Smith, J. G. Sorce, K. Tanidis, C. Tao, G. Testera, R. Teyssier, S. Tosi, A. Troja, M. Tucci, C. Valieri, A. Venhola, D. Vergani, G. Verza, N. A. Walton

The Euclid survey aims to measure the spectroscopic redshift of emission-line galaxies by identifying the H$\,{\alpha}$ line in their slitless spectra. This method is sensitive to the signal-to-noise ratio of the line, as noise fluctuations or other strong emission lines can be misidentified as H$\,{\alpha}$, depending on redshift. These effects lead to catastrophic redshift errors and the inclusion of interlopers in the sample. We forecast t... more
The Euclid survey aims to measure the spectroscopic redshift of emission-line galaxies by identifying the H$\,{\alpha}$ line in their slitless spectra. This method is sensitive to the signal-to-noise ratio of the line, as noise fluctuations or other strong emission lines can be misidentified as H$\,{\alpha}$, depending on redshift. These effects lead to catastrophic redshift errors and the inclusion of interlopers in the sample. We forecast the impact of such redshift errors on galaxy clustering measurements. In particular, we study the effect of interloper contamination on the two-point correlation function (2PCF), the growth rate of structures, and the Alcock-Paczynski (AP) parameters. We analyze 1000 synthetic spectroscopic catalogues, the EuclidLargeMocks, designed to match the area and selection function of the Data Release 1 (DR1) sample. We estimate the 2PCF of the contaminated catalogues, isolating contributions from correctly identified galaxies and from interlopers. We explore different models with increasing complexity to describe the measured 2PCF at fixed cosmology. Finally, we perform a cosmological inference and evaluate the systematic error on the inferred $f\sigma_8$, $\alpha_{\parallel}$ and $\alpha_{\perp}$ values associated with different models. Our results demonstrate that a minimal modelling approach, which only accounts for an attenuation of the clustering signal regardless of the type of contaminants, is sufficient to recover the correct values of $f\sigma_8$, $\alpha_{\parallel}$, and $\alpha_{\perp}$ at DR1. The accuracy and precision of the estimated AP parameters are largely insensitive to the presence of interlopers. The adoption of a minimal model induces a 1%-3% systematic error on the growth rate of structure estimation, depending on the redshift. However, this error remains smaller than the statistical error expected for the Euclid DR1 analysis. less
Cosmology and Nongalactic Astrophysics
Cluster Lensing Mass Inversion (CLUMI+): Combining Dynamics and Weak Lensing around Galaxy Clusters

Cluster Lensing Mass Inversion (CLUMI+): Combining Dynamics and Weak Lensing around Galaxy Clusters

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By: Keiichi Umetsu, Michele Pizzardo, Antonaldo Diaferio, Margaret J. Geller

We present CLUMI+, a self-consistent, multi-probe methodology for reconstructing the mass distribution in and around galaxy clusters by combining gravitational lensing and dynamical observations. Building on the joint-likelihood framework of Umetsu (2013), CLUMI+ integrates weak-lensing shear and magnification data with projected escape velocity measurements in the cluster infall region, yielding tighter constraints on the gravitational poten... more
We present CLUMI+, a self-consistent, multi-probe methodology for reconstructing the mass distribution in and around galaxy clusters by combining gravitational lensing and dynamical observations. Building on the joint-likelihood framework of Umetsu (2013), CLUMI+ integrates weak-lensing shear and magnification data with projected escape velocity measurements in the cluster infall region, yielding tighter constraints on the gravitational potential without relying on equilibrium assumptions. The mass distribution is modeled using a flexible, piecewise-defined convergence profile that characterizes the azimuthally averaged surface mass density within the lensing field, transitioning to a projected power-law form at larger radii where phase-space constraints complement lensing. Additional strong-lensing constraints are incorporated via central aperture-mass measurements, enabling full-scale mass reconstruction from the cluster core to the outskirts. We validate CLUMI+ using synthetic weak-lensing and phase-space data for a massive cluster from the IllustrisTNG simulations, demonstrating unbiased recovery of projected and three-dimensional mass profiles and achieving 10%--30% improvement in precision at large radii. As a case study, we apply CLUMI+ to Abell 2261, combining Subaru and Hubble Space Telescope weak+strong lensing data with spectroscopic measurements from the Hectospec Cluster Survey. This analysis demonstrates the power of multi-probe, equilibrium-free modeling for robust cluster mass reconstruction. less
Cosmology and Nongalactic Astrophysics
Gravitational waves from low-scale cosmic strings without scaling

Gravitational waves from low-scale cosmic strings without scaling

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By: Kai Schmitz, Tobias Schröder

Cosmic strings are predicted in many extensions of the Standard Model and constitute a plausible source of gravitational waves (GWs) from the early Universe. In a previous article [1], we pointed out that the GW spectrum from a population of string loops in the scaling regime can exhibit a sharp cutoff frequency associated with the fundamental oscillation mode of string loops. In this paper, we study the effect of particle decay due to kink-k... more
Cosmic strings are predicted in many extensions of the Standard Model and constitute a plausible source of gravitational waves (GWs) from the early Universe. In a previous article [1], we pointed out that the GW spectrum from a population of string loops in the scaling regime can exhibit a sharp cutoff frequency associated with the fundamental oscillation mode of string loops. In this paper, we study the effect of particle decay due to kink-kink collisions and cusps on the GW spectrum in the nonscaling scenario introduced in Ref. [2]. We find analytical conditions for the existence of a cutoff frequency in the fundamental spectrum and provide expressions for this frequency. In large regions of parameter space, our results in the nonscaling model turn out to be identical to those in the scaling model. Finally, we demonstrate how the spectrum changes when transitioning from the regime with a cutoff frequency to the regime without a cutoff frequency. Our analytical estimates are validated at qualitatively different benchmark points by comparing them with numerical spectra. less
Cosmology and Nongalactic Astrophysics
Extracting local velocity from cosmic dipole using simulations

Extracting local velocity from cosmic dipole using simulations

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By: Mohit Panwar, Akash Gandhi, Pankaj Jain

Our velocity with respect to the cosmic frame of rest leads to a dipole in the number count distribution of galaxies. The dipole depends on the source spectrum, which is usually assumed to be a power law, $S(\nu) \propto \nu^{-\alpha}$ and on the flux dependence of the number density of sources. The latter is also generally assumed to be a power law, parametrised with exponent $x$. The velocity can be extracted from the observed dipole once t... more
Our velocity with respect to the cosmic frame of rest leads to a dipole in the number count distribution of galaxies. The dipole depends on the source spectrum, which is usually assumed to be a power law, $S(\nu) \propto \nu^{-\alpha}$ and on the flux dependence of the number density of sources. The latter is also generally assumed to be a power law, parametrised with exponent $x$. The velocity can be extracted from the observed dipole once the two parameters $x$ and $\alpha$ are known. The standard procedure uses the mean value of $\alpha$ across the entire sample, and the parameter $x$ is inferred by fitting the cumulative number count, $\frac{dN}{d\Omega}(>S_*) \propto S_*^{-x}$, near the flux limit $S_*$ of the survey. Here, we introduce a simulation procedure to extract the velocity which directly uses the $\alpha$ values of each source rather than their mean and does not rely on the functional form of the cumulative number count near the flux limit. We apply this to the quasar sample in CatWISE2020 data and find that the final results differ from the standard procedure by approximately one sigma. less
Cosmology and Nongalactic Astrophysics
Reanalysis of Stage-III cosmic shear surveys: A comprehensive study of shear diagnostic tests

Reanalysis of Stage-III cosmic shear surveys: A comprehensive study of shear diagnostic tests

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By: Jazmine Jefferson, Yuuki Omori, Chihway Chang, Shrihan Agarwal, Joe Zuntz, Marika Asgari, Marco Gatti, Benjamin Giblin, Claire-Alice Hébert, Mike Jarvis, Eske M. Pedersen, Judit Prat, Theo Schutt, Tianqing Zhang, the LSST Dark Energy Science Collaboration

In recent years, weak lensing shear catalogs have been released by various Stage-III weak lensing surveys including the Kilo-Degree Survey, the Dark Energy Survey, and the Hyper Suprime-Cam Subaru Strategic Program. These shear catalogs have undergone rigorous validation tests to ensure that the residual shear systematic effects in the catalogs are subdominant relative to the statistical uncertainties, such that the resulting cosmological con... more
In recent years, weak lensing shear catalogs have been released by various Stage-III weak lensing surveys including the Kilo-Degree Survey, the Dark Energy Survey, and the Hyper Suprime-Cam Subaru Strategic Program. These shear catalogs have undergone rigorous validation tests to ensure that the residual shear systematic effects in the catalogs are subdominant relative to the statistical uncertainties, such that the resulting cosmological constraints are unbiased. While there exists a generic set of tests that are designed to probe certain systematic effects, the implementations differ slightly across the individual surveys, making it difficult to make direct comparisons. In this paper, we use the TXPipe package to conduct a series of predefined diagnostic tests across three public shear catalogs -- the 1,000 deg$^2$ KiDS-1000 shear catalog, the Year 3 DES-Y3 shear catalog, and the Year 3 HSC-Y3 shear catalog. We attempt to reproduce the published results when possible and perform key tests uniformly across the surveys. While all surveys pass most of the null tests in this study, we find two tests where some of the surveys fail. Namely, we find that when measuring the tangential ellipticity around bright and faint star samples, KiDS-1000 fails depending on whether the samples are weighted, with a $\chi^2$/dof of 185.3/13 for faint stars. We also find that DES-Y3 and HSC-Y3 fail the $B$-mode test when estimated with the Hybrid-$E$/$B$ method, with a $\chi^2$/dof of 37.9/10 and 36.0/8 for the fourth and third autocorrelation bins. We assess the impacts on the $\Omega_{\rm m}$ - S$_{8}$ parameter space by comparing the posteriors of a simulated data vector with and without PSF contamination -- we find negligible effects in all cases. Finally, we propose strategies for performing these tests on future surveys such as the Vera C. Rubin Observatory's Legacy Survey of Space and Time. less
Cosmology and Nongalactic Astrophysics
J-PAS and PFS surveys in the era of dark energy and neutrino mass measurements

J-PAS and PFS surveys in the era of dark energy and neutrino mass measurements

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By: Fuxing Qin, Yuting Wang, Gong-Bo Zhao

Fisher-matrix forecasts are presented for the cosmological surveys of the Javalambre Physics of the Accelerating Universe Astrophysical Survey (J-PAS) and the Subaru Prime Focus Spectrograph (PFS). The wide, low-redshift coverage of J-PAS and the high-density, high-redshift mapping of PFS are strongly complementary: combining the two reduces marginalized uncertainties on all primary parameters compared with either survey individually. Adding ... more
Fisher-matrix forecasts are presented for the cosmological surveys of the Javalambre Physics of the Accelerating Universe Astrophysical Survey (J-PAS) and the Subaru Prime Focus Spectrograph (PFS). The wide, low-redshift coverage of J-PAS and the high-density, high-redshift mapping of PFS are strongly complementary: combining the two reduces marginalized uncertainties on all primary parameters compared with either survey individually. Adding the joint J-PAS+PFS data to next-generation CMB measurements from CMB-S4 and \textsc{LiteBird} yields an expected precision of $\sigma(\sum m_\nu)=0.017\,$eV in the $\Lambda$CDM$+\sum m_\nu+N_{\rm eff}$ framework, sufficient to disfavour the inverted neutrino hierarchy at $2.35\,\sigma$ if the true mass sum equals the normal-ordering minimum. Motivated by recent DESI results, we also forecast within a $w_0w_a$CDM$+\sum m_\nu+N_{\rm eff}$ cosmology, adopting the DESI\,DR2 best-fit values ($w_0=-0.758$, $w_a=-0.82$) as fiducial. The combination CMB+J-PAS+PFS then delivers $\sigma(w_0)=0.044$ and $\sigma(w_a)=0.18$, corresponding to a $5.1\,\sigma$ preference for a time-varying dark-energy equation of state. These findings show that J-PAS and PFS, especially when coupled with Stage-IV CMB observations, will provide competitive tests of neutrino physics and the dynamics of cosmic acceleration. less
Cosmology and Nongalactic Astrophysics
Dynamical Dark Energy Emerges from Massive Gravity

Dynamical Dark Energy Emerges from Massive Gravity

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By: Juri Smirnov

In this work, we demonstrate that a dynamical dark energy component predicted by massive gravity gives rise to a distinctive evolution of the equation of state. This scenario is favoured over the standard $\Lambda$CDM model when confronted with the latest combined datasets from the Dark Energy Spectroscopic Instrument (DESI), the cosmic microwave background (CMB), and supernova observations. The model stands out as a rare example of a healthy... more
In this work, we demonstrate that a dynamical dark energy component predicted by massive gravity gives rise to a distinctive evolution of the equation of state. This scenario is favoured over the standard $\Lambda$CDM model when confronted with the latest combined datasets from the Dark Energy Spectroscopic Instrument (DESI), the cosmic microwave background (CMB), and supernova observations. The model stands out as a rare example of a healthy, self-consistent theory that accommodates phantom dark energy while maintaining a technically natural, small asymptotic cosmological constant. Our analysis indicates a preferred graviton mass of approximately $5 \times 10^{-33} \text{eV}$, suggesting the emergence of a new cosmological length scale. This leads to a maximal deviation of the equation of state around $z \sim 2.5$, a prediction that will be robustly tested by upcoming, deeper surveys of baryon acoustic oscillations. less
Cosmology and Nongalactic Astrophysics
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