Polarization of Gamma-Ray Burst Afterglows in the Context of Non-axisymmetric Structured Jets
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 nonuniform magnetic dissipation processes or the precession of the central engine) may generate asymmetric jet structures, which are cha...
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IOP Publishing
2024-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/ad9004 |
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| author | Jin-Da Li He Gao Shunke Ai Wei-Hua Lei |
| author_facet | Jin-Da Li He Gao Shunke Ai Wei-Hua Lei |
| author_sort | Jin-Da Li |
| collection | DOAJ |
| description | 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 nonuniform magnetic dissipation processes or the precession of the central engine) may generate asymmetric jet structures, which are characterized by multiple fluctuations in the light curve of the 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 GRB 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 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 the future identification of potential GRBs with asymmetric jet structures. |
| format | Article |
| id | doaj-art-7b48064d6c494f66a79479ff765fc9bc |
| institution | Kabale University |
| issn | 1538-4357 |
| language | English |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj-art-7b48064d6c494f66a79479ff765fc9bc2024-12-31T04:44:04ZengIOP PublishingThe Astrophysical Journal1538-43572024-01-01978212410.3847/1538-4357/ad9004Polarization of Gamma-Ray Burst Afterglows in the Context of Non-axisymmetric Structured JetsJin-Da Li0He Gao1https://orcid.org/0000-0003-2516-6288Shunke Ai2https://orcid.org/0000-0002-9165-8312Wei-Hua Lei3Institute for Frontier in Astronomy and Astrophysics, Beijing Normal University , Beijing 102206, People’s Republic of China ; gaohe@bnu.edu.cn; School of Physics and Astronomy, Beijing Normal University , Beijing 100875, People’s Republic of ChinaInstitute for Frontier in Astronomy and Astrophysics, Beijing Normal University , Beijing 102206, People’s Republic of China ; gaohe@bnu.edu.cn; School of Physics and Astronomy, Beijing Normal University , Beijing 100875, People’s Republic of ChinaDepartment of Astronomy, School of Physics and Technology, Wuhan University , Wuhan 430072, People’s Republic of China; Niels Bohr International Academy and DARK, Niels Bohr Institute , University of Copenhagen, Blegdamsvej 17, 2100, Copenhagen, DenmarkDepartment of Astronomy, School of Physics, Huazhong University of Science and Technology , Wuhan, Hubei 430074, People’s Republic of ChinaAs 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 nonuniform magnetic dissipation processes or the precession of the central engine) may generate asymmetric jet structures, which are characterized by multiple fluctuations in the light curve of the 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 GRB 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 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 the future identification of potential GRBs with asymmetric jet structures.https://doi.org/10.3847/1538-4357/ad9004Gamma-ray bursts |
| spellingShingle | Jin-Da Li He Gao Shunke Ai Wei-Hua Lei Polarization of Gamma-Ray Burst Afterglows in the Context of Non-axisymmetric Structured Jets The Astrophysical Journal Gamma-ray bursts |
| title | Polarization of Gamma-Ray Burst Afterglows in the Context of Non-axisymmetric Structured Jets |
| title_full | Polarization of Gamma-Ray Burst Afterglows in the Context of Non-axisymmetric Structured Jets |
| title_fullStr | Polarization of Gamma-Ray Burst Afterglows in the Context of Non-axisymmetric Structured Jets |
| title_full_unstemmed | Polarization of Gamma-Ray Burst Afterglows in the Context of Non-axisymmetric Structured Jets |
| title_short | Polarization of Gamma-Ray Burst Afterglows in the Context of Non-axisymmetric Structured Jets |
| title_sort | polarization of gamma ray burst afterglows in the context of non axisymmetric structured jets |
| topic | Gamma-ray bursts |
| url | https://doi.org/10.3847/1538-4357/ad9004 |
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