The propagation-induced circular polarization of fast radio bursts in relativistic plasma
- 1School of Astronomy and Space Science, Nanjing University
Abstract
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. The observed CP may result from intrinsic radiation processes 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.
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BibTeX
@article{z2026propagationinduced,
title = {{The propagation-induced circular polarization of fast radio bursts in relativistic plasma}},
author = {Zhao Z. Y. and Wang F. Y.},
journal = {Astronomy \& Astrophysics},
year = {2026},
month = oct,
doi = {10.1051/0004-6361/202557867},
url = {https://doi.org/10.1051/0004-6361/202557867},
note = {CC BY},
}
RIS
TY - JOUR
TI - The propagation-induced circular polarization of fast radio bursts in relativistic plasma
AU - Zhao Z. Y.
AU - Wang F. Y.
PY - 2026
DA - 2026/10/24
JO - Astronomy & Astrophysics
DO - 10.1051/0004-6361/202557867
UR - https://doi.org/10.1051/0004-6361/202557867
AB - 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. The observed CP may result from intrinsic radiation processes 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.
SN - 0004-6361
SN - 1432-0746
ER -