Synchrotron Self-Compton Emission in the Two-Component Jet Model for Gamma-Ray Bursts
Synchrotron Self-Compton Emission in the Two-Component Jet Model for Gamma-Ray Bursts
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DOI：
10.1016/j.jheap.2022.12.004
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发表时间：
2022-08
影响因子：
3.8
通讯作者：
Yuri Sato;K. Obayashi;B. Zhang;S. Tanaka;K. Murase;Y. Ohira;R. Yamazaki
中科院分区：
文献类型：
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作者：
Yuri Sato;K. Obayashi;B. Zhang;S. Tanaka;K. Murase;Y. Ohira;R. Yamazaki
伽马射线暴(GRB)是由相对论喷流引起的高能量光子(瞬时发射)的强烈爆发。发射后，从无线电到超高能伽马射线的多波长余辉持续几天以上。在过去的三年里，利用地面成像大气切伦科夫望远镜，如主要大气伽马成像切伦科夫(MAGIC)望远镜和高能立体系统(HESS)，探测了来自四个伽玛暴(伽马暴180720B、190114C、190829A和201216C)的VHE伽马射线光子。其中一颗是伽玛暴19082 9A，其X射线和光学谱带在1.4×10 3 S处出现消色差峰，属于低亮度伽玛暴。在此之前，我们提出了一个两组分喷流模型，其中“窄喷流”具有较小的初始张开半角θ=0.015 rad和大体积洛伦兹因子Γ_0=350，而“宽喷流”具有θ_0=0.1rad和Γ_0=20。窄喷流解释了早期的X射线和光学发射，以及在离轴观察情况下明显较小的各向同性伽马射线能量和峰值能量。此外，宽急流还发出了晚期X射线和射电(1.3 GHz和15.5 GHz)余辉。在这里，我们用同步加速器自康普顿(SSC)辐射计算了VHe伽马射线通量。我们的双组分喷流模型很好地解释了包括VHe伽马射线发射在内的多波长余辉现象。我们的双组分喷流的余辉发射也与伽玛暴180720B、190114C和201216C的观测结果一致，当这些喷流轴向观察时。此外，我们还讨论了切伦科夫望远镜阵列(CTA)对离轴孤儿余辉的探测能力。
Gamma-ray bursts (GRBs) are intense bursts of high-energy photons (prompt emissions) caused by relativistic jets. After the emissions, multi-wavelength afterglows, from radio to very-high-energy (VHE) gamma-ray, last for more than a few days. In the past three years, the VHE gamma-ray photons from four GRBs (GRBs 180720B, 190114C, 190829A and 201216C) were detected by ground-based Imaging Atmospheric Cherenkov Telescopes, such as the Major Atmospheric Gamma Imaging Cherenkov (MAGIC) telescopes and the High Energy Stereoscopic System (HESS). One of them, GRB 190829A, had some peculiar features of showing achromatic peaks in X-ray and optical bands at 1.4× 10 3 s and being classified as low-luminosity GRBs. Previously, we proposed a two-component jet model, which has ‘narrow jet’with a small initial opening half-angle θ 0= 0.015 rad and large bulk Lorentz factor Γ 0= 350, and ‘wide jet’with θ 0= 0.1 rad and Γ 0= 20. The narrow jet explained the early X-ray and optical emissions and apparently small isotropic gamma-ray energy and peak energy in the off-axis viewing case. Furthermore, the late X-ray and radio (1.3 and 15.5 GHz) afterglows were emitted from the wide jet. Here, we calculate the VHE gamma-ray flux by the synchrotron self-Compton (SSC) emission. The multi-wavelength afterglows of GRB 190829A including the VHE gamma-ray emission are well explained by our two-component jet model. The afterglow emissions from our two-component jet are also consistent with the observational results of GRBs 180720B, 190114C and 201216C, when the jets are viewed on-axis. Furthermore, we discuss the detectability of off-axis orphan afterglows by the Cherenkov Telescope Array (CTA).