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Main Authors: Zhao, Z. Y., Wang, F. Y.
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2408.04401
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author Zhao, Z. Y.
Wang, F. Y.
author_facet Zhao, Z. Y.
Wang, F. Y.
contents Although the physical origin of fast radio bursts (FRBs) remains unknown, magnetars are the most likely candidates. The polarization properties of FRBs offer crucial insights into their origins and radiation mechanisms. Significant circular polarization (CP) has been observed in some FRBs. CP may result from intrinsic radiation or propagation effects, both within and outside the magnetosphere. Recent observations indicate that polarization properties of FRB 20201124A can change over short timescales (about tens of milliseconds), challenging models that attribute CP to out-of-magnetosphere emission and propagation. Additionally, some magnetospheric radiation models predict that bursts with high CP produced by off-axis emission will be systematically fainter, which contradicts the observations. We propose that CP arises from magnetospheric propagation effects caused by relativistic plasma. We identify the conditions under which high CP occurs, finding it to be rare. Moreover, our model accounts for the more commonly observed low CP and the varying handedness of CP.
format Preprint
id arxiv_https___arxiv_org_abs_2408_04401
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The propagation-induced circular polarization of fast radio bursts in relativistic plasma
Zhao, Z. Y.
Wang, F. Y.
High Energy Astrophysical Phenomena
Although the physical origin of fast radio bursts (FRBs) remains unknown, magnetars are the most likely candidates. The polarization properties of FRBs offer crucial insights into their origins and radiation mechanisms. Significant circular polarization (CP) has been observed in some FRBs. CP may result from intrinsic radiation or propagation effects, both within and outside the magnetosphere. Recent observations indicate that polarization properties of FRB 20201124A can change over short timescales (about tens of milliseconds), challenging models that attribute CP to out-of-magnetosphere emission and propagation. Additionally, some magnetospheric radiation models predict that bursts with high CP produced by off-axis emission will be systematically fainter, which contradicts the observations. We propose that CP arises from magnetospheric propagation effects caused by relativistic plasma. We identify the conditions under which high CP occurs, finding it to be rare. Moreover, our model accounts for the more commonly observed low CP and the varying handedness of CP.
title The propagation-induced circular polarization of fast radio bursts in relativistic plasma
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2408.04401