Probing Particle Acceleration through Broadband Early Afterglow Emission of MAGIC Gamma-Ray Burst GRB 190114C
Probing Particle Acceleration through Broadband Early Afterglow Emission of MAGIC Gamma-Ray Burst GRB 190114C
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DOI：
10.3847/1538-4357/abc82c
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发表时间：
2020-07
期刊：
影响因子：
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通讯作者：
K. Asano;K. Murase;K. Toma
中科院分区：
文献类型：
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作者：
K. Asano;K. Murase;K. Toma
主要大气伽马成像切伦科夫望远镜（MAGIC）探测到GRB 190114C的伽马射线余辉，它可以约束冲击加热等离子体发射非热发射的微观参数。针对这一事件的早期余辉，我们利用含时程序数值模拟了星周介质为恒定风时的光谱和多波长光变曲线。我们的研究结果表明，在最高能量的电子加速时标可能是短于20倍的陀螺周期再现GeV的伽马射线通量和费米报告的光谱指数。这给出了一个有趣的约束的加速效率为韦伯介导的冲击。我们还限制了非热电子的数量分数fe和热电子的温度。早期的光发射可以用同步热辐射来解释，其中Fe <0.01。另一方面，X射线光变曲线限制了从质子到热电子的有效能量转移，并且如果热电子的能量分数大于10%，则需要Fe = 1。在这项工作中获得的参数约束提供了重要的线索，探测等离子体物理与相对论冲击。
Major Atmospheric Gamma Imaging Cerenkov Telescopes (MAGIC) detected the gamma-ray afterglow of GRB 190114C, which can constrain microscopic parameters of the shock-heated plasma emitting non-thermal emission. Focusing on the early afterglow of this event, we numerically simulate the spectrum and multi-wavelength light curves with constant and wind-like circumstellar medium using a time-dependent code. Our results show that the electron acceleration timescale at the highest energies is likely shorter than 20 times the gyroperiod to reproduce the GeV gamma-ray flux and its spectral index reported by Fermi. This gives an interesting constraint on the acceleration efficiency for Weibel-mediated shocks. We also constrain the number fraction of non-thermal electrons fe, and the temperature of the thermal electrons. The early optical emission can be explained by the thermal synchrotron emission with fe ≲ 0.01. On the other hand, the X-ray light curves restrict efficient energy transfer from protons to the thermal electrons, and fe ∼ 1 is required if the energy fraction of the thermal electrons is larger than ∼10%. The parameter constraints obtained in this work give important clues to probing plasma physics with relativistic shocks.