Is gamma-ray burst polarization from photosphere emission?
Fuente:
arXiv
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| Autori principali: | , , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2025
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| _version_ | 1866911438397767680 |
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| author | Meng, Yan-Zhi Zhong, Shu-Qing Gu, Jia-Hong Li, Xin-Fei Zhao, Xiaozhou |
| author_facet | Meng, Yan-Zhi Zhong, Shu-Qing Gu, Jia-Hong Li, Xin-Fei Zhao, Xiaozhou |
| contents | Context: Despite more than half a century of research, the dominant radiation mechanism of gamma-ray burst (GRB) prompt emission remains unsolved. Some progress has been made through the analyses of the observational spectra of Swift/BAT, Konus/Wind, and Fermi/GBM, as well as the spectra of the photosphere or synchrotron models, but it is still insufficient to pin down the answer.
Aims: Combining the spectral and polarization observations, we seek new criteria for model evaluation.
Methods: We thoughtfully investigate the polarization samples of POLAR and AstroSAT, combining the light curve, the spectral and the polarization parameters.
Results: The power-law shape of the X-ray afterglows, the $T_{90} \propto (L_{\text{iso}})^{-0.5}$ correlation, and the hard low-energy spectral index $α$ are revealed, thus supporting the photosphere origin. Furthermore, we discover the positive correlation of the $α$ and the polarization degree (PD), which can be consistently explained by the photosphere polarization scenario involving the jet asymmetry from a moderate viewing angle of $θ_{v}$=0.015. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2503_01558 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Is gamma-ray burst polarization from photosphere emission? Meng, Yan-Zhi Zhong, Shu-Qing Gu, Jia-Hong Li, Xin-Fei Zhao, Xiaozhou High Energy Astrophysical Phenomena Context: Despite more than half a century of research, the dominant radiation mechanism of gamma-ray burst (GRB) prompt emission remains unsolved. Some progress has been made through the analyses of the observational spectra of Swift/BAT, Konus/Wind, and Fermi/GBM, as well as the spectra of the photosphere or synchrotron models, but it is still insufficient to pin down the answer. Aims: Combining the spectral and polarization observations, we seek new criteria for model evaluation. Methods: We thoughtfully investigate the polarization samples of POLAR and AstroSAT, combining the light curve, the spectral and the polarization parameters. Results: The power-law shape of the X-ray afterglows, the $T_{90} \propto (L_{\text{iso}})^{-0.5}$ correlation, and the hard low-energy spectral index $α$ are revealed, thus supporting the photosphere origin. Furthermore, we discover the positive correlation of the $α$ and the polarization degree (PD), which can be consistently explained by the photosphere polarization scenario involving the jet asymmetry from a moderate viewing angle of $θ_{v}$=0.015. |
| title | Is gamma-ray burst polarization from photosphere emission? |
| topic | High Energy Astrophysical Phenomena |
| url | https://arxiv.org/abs/2503.01558 |