Time-integrated Polarizations of the GRB X-Ray Flares
Despite decades of studies, the energy dissipation mechanism of the X-ray flares in the afterglow phase of gamma-ray bursts (GRBs) is still debated. If the jet is dominated by the Poynting flux, there would be a large-scale ordered magnetic field in it, and the X-ray flares might be powered by the m...
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| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/1538-4357/adee19 |
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| Summary: | Despite decades of studies, the energy dissipation mechanism of the X-ray flares in the afterglow phase of gamma-ray bursts (GRBs) is still debated. If the jet is dominated by the Poynting flux, there would be a large-scale ordered magnetic field in it, and the X-ray flares might be powered by the magnetic reconnection process. However, if the jet is dynamical energy dominated and the magnetic field is random, the X-ray flares may be generated by the internal shocks of the cold outflow or by the synchrotron emission escaping from the hot plasma. Polarization is very sensitive to the magnetic field configuration in the radiation region; hence, it can be used as a probe of the magnetic field and the corresponding energy dissipation mechanism in the radiation region. In this paper, the magnetic reconnection model, the internal shock model, and the photosphere model are all described by a simple parametric model to study the time-integrated polarizations of the GRB X-ray flares. We found the time-integrated polarization degree of the GRB X-ray flares would concentrate on high values for the magnetic reconnection process and around zero for the internal shock or the photosphere origin. The influences of the parameters on the time-integrated polarizations are also discussed. Therefore, the statistical properties of the polarizations obtained by the dedicated polarization detector, Low-energy Polarimetry Detector on board POLAR-2, would make a distinction of the energy dissipation processes in the radiation region of the GRB X-ray flares. |
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| ISSN: | 1538-4357 |