Mitigating antenna gain errors with HyFoReS in CHIME simulations

Fuente: arXiv
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Hauptverfasser: Wang, Haochen, Phoompuang, Panupong, Masui, Kiyoshi W., Chakraborty, Arnab, Foreman, Simon
Format: Preprint
Veröffentlicht: 2025
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author Wang, Haochen
Phoompuang, Panupong
Masui, Kiyoshi W.
Chakraborty, Arnab
Foreman, Simon
author_facet Wang, Haochen
Phoompuang, Panupong
Masui, Kiyoshi W.
Chakraborty, Arnab
Foreman, Simon
contents Hybrid Foreground Residual Subtraction (HyFoReS) is a new family of algorithms designed to remove systematics-induced foreground contamination for 21-cm intensity mapping data. Previously, the algorithm was shown to be effective in mitigating beam perturbations in sky maps from the Canadian Hydrogen Intensity Mapping Experiment (CHIME). In this study, we apply HyFoReS to CHIME simulations and test the algorithm's ability to mitigate antenna gain-type systematics in polarized visibilities. Simulating a two-cylinder telescope similar to the CHIME pathfinder, we find that HyFoReS reduces foreground bias caused by bandpass perturbations to a level below the thermal noise, provided that the RMS value of the perturbations is on the order of $10^{-4}$ or lower. When tested with complex antenna-dependent gain errors, HyFoReS can reduce residual foreground bias in the power spectrum by up to three orders of magnitude. While noise bias and second-order perturbations are currently the limiting factors for the algorithm, we have demonstrated that HyFoReS can suppress gain-induced foreground leakage in polarized data from 21-cm telescopes, aiding in the detection of the 21-cm auto-power spectrum for hydrogen intensity mapping experiments.
format Preprint
id arxiv_https___arxiv_org_abs_2506_09170
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Mitigating antenna gain errors with HyFoReS in CHIME simulations
Wang, Haochen
Phoompuang, Panupong
Masui, Kiyoshi W.
Chakraborty, Arnab
Foreman, Simon
Instrumentation and Methods for Astrophysics
Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
Hybrid Foreground Residual Subtraction (HyFoReS) is a new family of algorithms designed to remove systematics-induced foreground contamination for 21-cm intensity mapping data. Previously, the algorithm was shown to be effective in mitigating beam perturbations in sky maps from the Canadian Hydrogen Intensity Mapping Experiment (CHIME). In this study, we apply HyFoReS to CHIME simulations and test the algorithm's ability to mitigate antenna gain-type systematics in polarized visibilities. Simulating a two-cylinder telescope similar to the CHIME pathfinder, we find that HyFoReS reduces foreground bias caused by bandpass perturbations to a level below the thermal noise, provided that the RMS value of the perturbations is on the order of $10^{-4}$ or lower. When tested with complex antenna-dependent gain errors, HyFoReS can reduce residual foreground bias in the power spectrum by up to three orders of magnitude. While noise bias and second-order perturbations are currently the limiting factors for the algorithm, we have demonstrated that HyFoReS can suppress gain-induced foreground leakage in polarized data from 21-cm telescopes, aiding in the detection of the 21-cm auto-power spectrum for hydrogen intensity mapping experiments.
title Mitigating antenna gain errors with HyFoReS in CHIME simulations
topic Instrumentation and Methods for Astrophysics
Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2506.09170