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arXiv 0706.0669astro-ph
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雨燕GRB 050802的双组分余辉

The Two-Component Afterglow of Swift GRB 050802

S. R. Oates, M. De Pasquale, M. J. Page, A. J. Blustin, S. Zane, K. McGowan, K. O. Mason, T. S. Poole, P. Schady, P. W. A. Roming, K. L. Page, A. Falcone, N. Gehrels

摘要:

本文研究了GRB 050802,它的一个最好的例子,它的快速伽马射线暴余辉,显示在X射线光变曲线的中断,而光学对应衰减为一个单一的幂律。这个爆发有16.5等的光学明亮余辉,在雨燕上的UVOT的170- 650 nm光谱范围内被探测到。XRT和UVOT望远镜在初始触发后286秒开始观测,持续了1.2 x 10^6秒。X射线光变曲线由三个幂律段组成:上升到420 s,然后是缓慢衰减,α_2 = 0.63 +/- 0.03,直到5000 s,之后,光变曲线衰减得更快,斜率为α_3 = 1.59 +/- 0.03。在整个观测过程中,光学光变曲线呈单一的幂律衰减,α_O = 0.82 +/- 0.03。X射线数据本身与5000 s处的断裂一致,这是由于能量注入结束。模拟的光学X射线光谱能量分布,我们发现,光学余辉不能产生相同的组件作为X射线发射在晚些时候,排除了单组分余辉。因此,我们认为两个组件的射流模型,并发现,X射线和光学发射是最好的复制模型中,这两个组件的能量注入观察到的余辉的持续时间和X射线休息在5000秒是由于在狭窄的组件射流休息。这个明亮的、观测良好的爆发很可能是解释斯威夫特令人惊讶的发现的指南,斯威夫特发现爆发很少显示消色差的喷流中断。

英文摘要:

This paper investigates GRB 050802, one of the best examples of a it Swift gamma-ray burst afterglow that shows a break in the X-ray lightcurve, while the optical counterpart decays as a single power-law. This burst has an optically bright afterglow of 16.5 magnitude, detected throughout the 170-650nm spectral range of the UVOT on-board Swift. Observations began with the XRT and UVOT telescopes 286s after the initial trigger and continued for 1.2 x 10^6s. The X-ray lightcurve consists of three power-law segments: a rise until 420s, followed by a slow decay with alpha_2 = 0.63 +/- 0.03 until 5000s, after which, the lightcurve decays faster with a slope of alpha_3 = 1.59 +/- 0.03. The optical lightcurve decays as a single power-law with alpha_O = 0.82 +/- 0.03 throughout the observation. The X-ray data on their own are consistent with the break at 5000s being due to the end of energy injection. Modelling the optical to X-ray spectral energy distribution, we find that the optical afterglow can not be produced by the same component as the X-ray emission at late times, ruling out a single component afterglow. We therefore considered two-component jet models and find that the X-ray and optical emission is best reproduced by a model in which both components are energy injected for the duration of the observed afterglow and the X-ray break at 5000s is due to a jet break in the narrow component. This bright, well-observed burst is likely a guide for interpreting the surprising finding of Swift that bursts seldom display achromatic jet breaks.

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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