一种对伽玛暴瞬时谱的新解释

A new explanation to the prompt spectra of gamma-ray bursts

研究了幂律分布电子的同步曲率辐射在伽玛暴(gamma-ray burst,GRB)的物理条件下的表现,并用同步曲率辐射机制代替同步辐射来解释伽玛暴的瞬时谱,尤其是那些出现拐点和高能过剩的谱,还拟合了几个实际的有拐点和高能过剩的伽玛射线暴的瞬时谱.从中可以看出,同步曲率辐射机制对整个瞬时谱能够做出统一和合理的解释.在对高能过剩部分的解释中,同步曲率辐射机制不需再人为引入任何其他机制,因此可调参数少.此外,该机制还能对发射区磁场给出更加详细的描述,尤其是对磁场的曲率半径有了严格的约束,因此对磁场的形成机制给出严格的限制,支持了磁场产生于激波的理论模型.将来对更高能部分的更精细的观测将能够对我们的模型进行进一步检验.最后用同步曲率辐射对GRB 941017的谱的瞬时谱部分的演化进行了拟合和讨论.

The effects of the synchro-curvature mechanism of electrons with a power law energy distribution was studied in the physical conditions of gamma-ray bursts（GRBs）, and the synchro-curvature mechanism was applied instead of the synchrotron mechanism to study the prompt spectra of GRBs, especially those with a turnoff point and a high-energy excess. Several spectra were fitted and very good results were obtained. It is shown that the synchro-curvature mechanism can give the whole prompt spectra a uniform and reasonable explanation. In addition, the synchro-curvature mechanism can give more detailed descriptions on the magnetic fields, especially the curvature radius. So, it can give strict constraints on the formation mechanism of magnetic fields and supports the model in which magnetic fields form in shocks. The synchro-curvature mechanism was used to fit and discuss the evolution of spectrum of GRB 941017.