X-RAYING EXTENDED EMISSION AND RAPID DECAY OF SHORT GAMMA-RAY BURSTS
X-RAYING EXTENDED EMISSION AND RAPID DECAY OF SHORT GAMMA-RAY BURSTS
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DOI：
10.1088/0004-637x/811/1/4
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发表时间：
2015-06
期刊：
影响因子：
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通讯作者：
Y. Kagawa;D. Yonetoku;T. Sawano;Asuka Toyanago;Takashi Nakamura;Keitaro Takahashi;K. Kashiyama;K. Ioka
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文献类型：
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作者：
Y. Kagawa;D. Yonetoku;T. Sawano;Asuka Toyanago;Takashi Nakamura;Keitaro Takahashi;K. Kashiyama;K. Ioka
短伽马射线暴（sgrb）的扩展发射是一个谜。通过对Swift-XRT观测到的9个最亮事件进行时间分辨光谱分析，我们将sgrb的早期x射线发射分为两种类型。一种是呈指数级快速衰减的扩展发射，它在SGRB触发后的数百秒内显示出明显的光谱软化，也被Swift-BAT探测到。另一个则是暗淡的余辉，仅在104秒内呈现幂律衰减。扩展辐射的时间衰减与光谱指数之间的相关性与均匀射流高纬度曲率辐射的α -β相关性不一致。观测到的过快衰减表明，辐射来自光球或斑状表面，并表明通过中心引擎（如黑洞的磁重联）停止。
Extended emission in short gamma-ray bursts (SGRBs) is a mystery. By conducting time-resolved spectral analyses of the nine brightest events observed by the Swift-XRT, we classify the early X-ray emission of SGRBs into two types. One is the extended emission with exponentially rapid decay, which shows significant spectral softening for hundreds of seconds after the SGRB trigger and is also detected by the Swift-BAT. The other is a dim afterglow that only shows power-law decay over 104 s. The correlations between the temporal decay and spectral indices of the extended emissions are inconsistent with the α–β correlation expected for the high-latitude curvature emission from a uniform jet. The observed too-rapid decay suggests that the emission is from a photosphere or a patchy surface, and manifests the stopping via a central engine such as magnetic reconnection at the black hole.