The Formation of Hard Very High Energy Spectra from Gamma-ray Burst Afterglows via Two-zone Synchrotron Self-Compton Emission
The Formation of Hard Very High Energy Spectra from Gamma-ray Burst Afterglows via Two-zone Synchrotron Self-Compton Emission
复制标题
通过两区同步加速器自康普顿发射从伽马射线暴余辉形成硬甚高能光谱
DOI：
10.3847/1538-4357/acc24e
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
F. Aharonian
中科院分区：
文献类型：
--
作者：
D. Khangulyan;Andrew M. Taylor;F. Aharonian
电子康普顿散射的目标光子进入伽玛射线能量带（逆康普顿散射; IC）通常预计占主导地位的甚高能量（VHE）的伽玛射线暴（GRB），特别是在余辉阶段的频谱。对于足够大的质心能量在这些碰撞中，电子反冲的影响开始减少散射截面（克莱因-西名制度）。与由相同电子产生的同步加速器光谱相比，在Klein-Nishina制度中产生的IC光谱更软并且具有更小的通量水平。利用H.E.S.S.已经揭示了一个意想不到的功能：VHE光谱的斜率与X射线光谱的斜率匹配良好，尽管预期对于IC生产工艺，Klein-Nishina效应的影响应该是强的。多波长光谱能量分布似乎与单区同步加速器自康普顿模型的预测不一致。我们研究了当两个区之间的磁场强度相差很大时，两个区的配置对IC发射特性的可能影响。来自强磁场区的同步加速器光子提供了用于冷却弱磁场区中的电子的主要目标，这导致硬电子分布的形成，并因此导致硬IC发射。我们表明，双区模型可以提供一个很好的描述斯威夫特的X射线望远镜和VHE H.E.S.S.数据
Electron Compton scattering of target photons into the gamma-ray energy band (inverse Compton scattering; IC) is commonly expected to dominate the very high energy (VHE) spectra in gamma-ray bursts (GRBs) especially during the afterglow phase. For sufficiently large center-of-mass energies in these collisions, the effect of the electron recoil starts reducing the scattering cross-section (the Klein–Nishina regime). The IC spectra generated in the Klein–Nishina regime is softer and has a smaller flux level compared to the synchrotron spectra produced by the same electrons. The detection of afterglow emission from nearby GRB190829A in the VHE domain with H.E.S.S. has revealed an unexpected feature: the slope of the VHE spectrum matches well the slope of the X-ray spectra, despite expectations that, for the IC production process, the impact of the Klein–Nishina effect should be strong. The multi-wavelength spectral energy distribution appears to be inconsistent with predictions of one-zone synchrotron–self-Compton models. We study the possible impact of two-zone configuration on the properties of IC emission when the magnetic field strength differs considerably between the two zones. Synchrotron photons from the strong magnetic field zone provide the dominant target for cooling of the electrons in the weak magnetic field zone, which results in a formation of hard electron distribution and consequently of a hard IC emission. We show that the two-zone model can provide a good description of the Swift's X-ray Telescope and VHE H.E.S.S. data.
DOI：
10.3847/1538-4357/ac0cfc
发表时间：
2020-12
期刊：
The Astrophysical Journal
影响因子：
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作者：
B. Zhang;K. Murase;P. Veres;P. M'esz'aros
通讯作者：
B. Zhang;K. Murase;P. Veres;P. M'esz'aros