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arXiv 0707.0952astro-ph
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GRB 050820 a余辉的上升

The rise of the afterglow in GRB 050820a

F. Genet, F. Daigne, R. Mochkovitch

摘要:

RAPTOR望远镜记录的GRB 050820 a的早期光学余辉显示了即时发射和余辉初始上升的贡献。因此,它是非常适合的动力学演化的研究伽玛射线暴喷出物时,它首先经历了环境的减速效应。这是一个复杂的阶段,内部冲击、反向冲击和正向冲击都可能同时存在。我们已经开发了一个简化的模型,可以按照这些不同的冲击近似,但自洽的方式。并将其应用于GRB 050820a的瞬发光变曲线和余辉光变曲线。我们表明,余辉的上升过程中的即时发射有一些重要的后果。在内部冲击完成之前,反向冲击传播回喷出物中,这影响了伽马射线剖面的形状。当外部介质具有均匀密度时,我们得到最好的结果,但是获得即时和余辉发射的同时拟合并不容易。我们讨论了一些可能有助于改善这种情况的可能性。

英文摘要:

The early optical afterglow of GRB 050820a recorded by the RAPTOR telescope shows both a contribution from the prompt emission and the initial rise of the afterglow. It is therefore well-suited for the study of the dynamical evolution of the GRB ejecta when it first undergoes the decelerating effect of the environment. This is a complex phase where the internal, reverse, and forward shocks can all be present simultaneously. We have developed a simplified model that can follow these different shocks in an approximate, but self-consistent way. It is applied to the case of GRB 050820a to obtain the prompt and afterglow light curves. We show that the rise of the afterglow during the course of the prompt emission has some important consequences. The reverse shock propagates back into the ejecta before internal shocks are completed, which affects the shape of the gamma-ray profile. We get the best results when the external medium has a uniform density, but obtaining a simultaneous fit of the prompt and afterglow emission is not easy. We discuss a few possibilities that could help to improve this situation.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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