快速冷却电子的精确同步辐射谱与GRB辐射

The Precise Synchrotron Spectrum of Fast Cooling Electrons and the GRB Prompt Emission

普遍认为内激波中电子的同步辐射是γ射线暴快速光变辐射的主要辐射机制,但理论预言与观测结果始终符合不好.确认在内激波中电子因辐射损失而快速冷却,分析指出以往研究中求得的快速冷却电子同步辐射谱只是一个粗略的结果,由数值计算求得单电子快速冷却时的精确同步辐射谱,从而用一个统一模型合理解释观测到的长γ暴低能谱指数α的分布,并拟合α与vF_v谱的峰值能量E_p之间的相关.

It is believed commonly that the synchrotron emission of electrons within the shocked region is the leading radiation mechanism for GRB prompt emission. However, the theoretical prediction has not been conformed to observed results well. We confirm that the electrons within the shocked regions fast cool due to radiation losses on a time scale much shorter than the dynamical time of the system. It is also indicated that the synchrotron spectrum of fast cooling electrons obtained in the past is a rough results. We show the precise synchrotron spectrum of fast cooling electrons by numerical calculating and thereby explain the observed distribution of GRB low-energy spectrum index a reasonably. In addition,we fit the correlation between α and peak energy Ep of spectrum.