On the Diversity of Pulsar's Frequency-Dependent Circular Polarization

Fuente: arXiv
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Main Authors: Cao, Shunshun, Guo, Yanjun, Jiang, Jinchen, Lee, Kejia, Wang, Weiyang, Xu, Renxin
Format: Preprint
Published: 2025
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author Cao, Shunshun
Guo, Yanjun
Jiang, Jinchen
Lee, Kejia
Wang, Weiyang
Xu, Renxin
author_facet Cao, Shunshun
Guo, Yanjun
Jiang, Jinchen
Lee, Kejia
Wang, Weiyang
Xu, Renxin
contents The nature of coherent radio emission is still challenging even after more than half a century of pulsar discovery, but it is generally a consensus that single-pulse observations are essential for probing the magnetospheric dynamics, especially with the largest single-dish telescope FAST (Five-hundred-meter Aperture Spherical radio Telescope). This paper aims to explain the observed diversity of single pulse circular polarization, and to constrain the multiplicity and Lorentz factor of pulsar magnetospheric plasma, with the mode coupling model in the limiting polarization region. Assuming that circular polarization comes only from wave mode coupling, we apply a Bayesian analysis to the FAST observed single pulse circular polarization spectra, involving numerical solving of wave mode coupling equations, and analyze the posterior probability distribution functions of the parameters. Although the model fails to quantitatively fit most circular polarization spectra, circular polarization of different frequency evolution is reproduced. For three chosen pulsars, the Bayesian analysis constrains the multiplicity to be approximately $10^{0}\sim10^{2}$, and the Lorentz factor to be approximately $10^{0.5}\sim10^{2}$. Pulsar circular polarization could be induced by wave mode coupling. The plasma flow responsible for coherent radio emission carries only a very small fraction of the pulsar spin-down energy loss.
format Preprint
id arxiv_https___arxiv_org_abs_2512_19056
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On the Diversity of Pulsar's Frequency-Dependent Circular Polarization
Cao, Shunshun
Guo, Yanjun
Jiang, Jinchen
Lee, Kejia
Wang, Weiyang
Xu, Renxin
High Energy Astrophysical Phenomena
The nature of coherent radio emission is still challenging even after more than half a century of pulsar discovery, but it is generally a consensus that single-pulse observations are essential for probing the magnetospheric dynamics, especially with the largest single-dish telescope FAST (Five-hundred-meter Aperture Spherical radio Telescope). This paper aims to explain the observed diversity of single pulse circular polarization, and to constrain the multiplicity and Lorentz factor of pulsar magnetospheric plasma, with the mode coupling model in the limiting polarization region. Assuming that circular polarization comes only from wave mode coupling, we apply a Bayesian analysis to the FAST observed single pulse circular polarization spectra, involving numerical solving of wave mode coupling equations, and analyze the posterior probability distribution functions of the parameters. Although the model fails to quantitatively fit most circular polarization spectra, circular polarization of different frequency evolution is reproduced. For three chosen pulsars, the Bayesian analysis constrains the multiplicity to be approximately $10^{0}\sim10^{2}$, and the Lorentz factor to be approximately $10^{0.5}\sim10^{2}$. Pulsar circular polarization could be induced by wave mode coupling. The plasma flow responsible for coherent radio emission carries only a very small fraction of the pulsar spin-down energy loss.
title On the Diversity of Pulsar's Frequency-Dependent Circular Polarization
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2512.19056