Polarization of gamma-ray burst afterglows in the context of non-axisymmetric structured jets

Fuente: arXiv
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Main Authors: Li, Jin-Da, Gao, He, Ai, Shunke, Lei, Wei-Hua
Format: Preprint
Published: 2024
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author Li, Jin-Da
Gao, He
Ai, Shunke
Lei, Wei-Hua
author_facet Li, Jin-Da
Gao, He
Ai, Shunke
Lei, Wei-Hua
contents As the most energetic explosion in the universe, gamma-ray bursts (GRBs) are usually believed to be generated by relativistic jets. Some mechanisms (e.g. internal non-uniform magnetic dissipation processes or the precession of the central engine) may generate asymmetric jet structures, which is characterized by multiple fluctuations in the light curve of afterglow. Since the jet's structure introduces asymmetry in radiation around the line of sight (LOS), it is naturally expected that polarization will be observable. In this work, we reveal the polarization characteristics of gamma-ray burst afterglows with a non-axisymmetric structured jet. Our results show that the afterglow signal generally exhibits polarization, with the degree and evolution influenced by the specific jet structure, observing frequency, and the line of sight (LOS). The polarization degree is notably higher when the LOS is outside the jet. This degree fluctuates over time as different regions of radiation alternate in their dominance, which is accompanied by the rotation of the polarization angle and further reflects the intricate nature of the jet. Regarding its evolution over frequency, the polarization degree displays significant fluctuations at spectral breaks, with the polarization angle possibly undergoing abrupt changes. These features may provide strong evidence for future identification of potential GRBs with asymmetric jet structures.
format Preprint
id arxiv_https___arxiv_org_abs_2412_01228
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Polarization of gamma-ray burst afterglows in the context of non-axisymmetric structured jets
Li, Jin-Da
Gao, He
Ai, Shunke
Lei, Wei-Hua
High Energy Astrophysical Phenomena
As the most energetic explosion in the universe, gamma-ray bursts (GRBs) are usually believed to be generated by relativistic jets. Some mechanisms (e.g. internal non-uniform magnetic dissipation processes or the precession of the central engine) may generate asymmetric jet structures, which is characterized by multiple fluctuations in the light curve of afterglow. Since the jet's structure introduces asymmetry in radiation around the line of sight (LOS), it is naturally expected that polarization will be observable. In this work, we reveal the polarization characteristics of gamma-ray burst afterglows with a non-axisymmetric structured jet. Our results show that the afterglow signal generally exhibits polarization, with the degree and evolution influenced by the specific jet structure, observing frequency, and the line of sight (LOS). The polarization degree is notably higher when the LOS is outside the jet. This degree fluctuates over time as different regions of radiation alternate in their dominance, which is accompanied by the rotation of the polarization angle and further reflects the intricate nature of the jet. Regarding its evolution over frequency, the polarization degree displays significant fluctuations at spectral breaks, with the polarization angle possibly undergoing abrupt changes. These features may provide strong evidence for future identification of potential GRBs with asymmetric jet structures.
title Polarization of gamma-ray burst afterglows in the context of non-axisymmetric structured jets
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2412.01228