Flux Calibration of CHIME/FRB Intensity Data

AI: The accuracy of the flux calibration technique is not explicitly stated in this part of the paper. There is an estimation of the uncertainties on fluence and flux values using steady source transit data, including primary beam error and time error, but no specific measure of accuracy for the flux calibration technique is provided. The beam model accuracy is estimated to be within ${\sim}10\%$ for the main lobe of the primary beam, and the calibrated flux is accurate to within ${\sim}5\%$ when comparing CygA transit data calibrated using this conversion factor to the expected spectrum attenuated by the beam model, but these are specific cases and do not provide a general estimate of the accuracy of the flux calibration technique.

AI: The acronym "CHIME/FRB" stands for "Canadian Hydrogen Intensity Mapping Experiment/Fast Radio Burst".

AI: The language used in the paper may be difficult for non-experts to understand, especially without prior knowledge of the topics discussed.

AI: The Canadian Hydrogen Intensity Mapping Experiment/Fast Radio Burst (CHIME/FRB) is a radio telescope used to detect and study fast radio bursts (FRBs). CHIME/FRB forms a grid of 1,024 static beams for each polarization and frequency using an algorithm called Fast Fourier Transform (FFT) beamforming. The flux calibration pipeline was developed to obtain meaningful constraints on the flux and fluence of each detected FRB. The pipeline characterizes and corrects for the 30 MHz ripple empirically using daily transit observations of steady sources with known spectral properties, allowing for determination of the beamformer-to-Jansky (BF/Jy) conversion across the primary beam directly. CHIME/FRB detected an unprecedented number of FRBs within its first year of operation, leading to important discoveries including confirmation of the existence of FRB emission down to 400 MHz. The flux calibration pipeline is fully automated and configured to run in jobs distributed on a separate on-site compute cluster.

AI: - CHIME/FRB has 1,024 static beams that sample the field of view. - CHIME/FRB uses an algorithm called Fast Fourier Transform (FFT) beamforming to form beams in the North-South direction. - The CHIME's novel design introduces novel challenges for flux calibrating bursts detected in CHIME/FRB intensity data. - FRBs are assigned unique event ID numbers and beamformed intensity data containing the burst is saved in an on-site CHIME/FRB archiver with 450 TB of storage. - Several automated post-detection analyses are triggered in order to better characterize the burst properties, including the dispersion measure (DM) pipeline, the localization pipeline, and fitburst software. - The CHIME/FRB injections system provides infrastructure for generating synthetic FRBs with user-determined properties, injecting them into the real-time intensity data stream to be searched with the CHIME/FRB backend, and tracking the resulting properties measured from the real-time pipeline. - The primary beam response of CHIME/FRB is that of a single feed over a cylindrical reflector and varies smoothly as an elliptical shape spanning ${\sim}120^{\circ}$ North-South along the local meridian and ${\sim}2.5-1.3^{\circ}$ East-West ($400-800$\,MHz). - The primary beam exhibits more complicated variations resulting from reflections within the telescope and cross-talk between neighboring feeds on the focal line, including a $30$\,MHz ripple in the primary beam response as a function of frequency on the order of ${\sim}30{-}50\%$ in amplitude.