arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1503.00976astro-ph.HE
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伽玛暴光学余辉和X射线余辉的相关研究

A Correlated Study of Optical and X-ray Afterglows of GRBs

Liang Li, Xue-Feng Wu, Yong-Feng Huang, Xiang-Gao Wang, Qing-Wen Tang, Yun-Feng Liang, Bin-Bin Zhang, Yu Wang, Jin-Jun Geng, En-Wei Liang, Jian-Yan Wei, Bing Zhang, Felix Ryde

摘要:

我们研究了87个伽玛暴的广泛样本,其中有良好的采样和同步的光学和X射线光变曲线。我们提取最干净的可能的信号的余辉分量,并比较的时间行为的X射线光变曲线,观察到的雨燕XRT,光学数据,观察到的UVOT和地面望远镜为每个单独的爆发。总的来说,我们发现62\%的伽玛暴是符合标准的余辉模型。当调用更高级的建模时,我们样本中高达91%的爆发可能与外部冲击模型一致。这些爆发中的很大一部分与发生在恒定星际密度介质(ISM)中一致(61%),而其中只有39%发生在风状介质中。只有9个案例的余辉光变曲线完全符合标准火球模型的预测,在整个持续时间内观察到的两个能带中有一个单一的幂律衰减。特别是,对于具有色性行为的爆发,必须在光变曲线的有限段上进行额外的模型假设,以便使这些爆发完全符合外部冲击模型。有趣的是,对于54%的X射线和40%的光学波段观测,浅衰变($t^{\sim-0.5}$)周期的结束与射流破裂($t^{\sim-p}$)时间一致,导致衰变斜率的突然变化。在静止坐标系中,与外激波模型相一致的爆发部分与观测历元无关。此外,没有任何情况可以用冷却频率穿过X射线或光学带来解释。

英文摘要:

We study an extensive sample of 87 GRBs for which there are well sampled and simultaneous optical and X-ray light-curves. We extract the cleanest possible signal of the afterglow component, and compare the temporal behaviors of the X-ray light-curve, observed by Swift XRT, and optical data, observed by UVOT and ground-based telescopes for each individual burst. Overall we find 62\% GRBs that are consistent with the standard afterglow model. When more advanced modeling is invoked, up to 91\% of the bursts in our sample may be consistent with the external shock model. A large fraction of these bursts are consistent with occurring in a constant interstellar density medium (ISM) (61\%) while only 39\% of them occur in a wind-like medium. Only 9 cases have afterglow light-curves that exactly match the standard fireball model prediction, having a single power law decay in both energy bands which are observed during their entire duration. In particular, for the bursts with chromatic behavior additional model assumptions must be made over limited segments of the light-curves in order for these bursts to fully agree with the external shock model. Interestingly, for 54\% of the X-ray and 40\% of the optical band observations the end of the shallow decay ($t^{\sim-0.5}$) period coincides with the jet break ($t^{\sim-p}$) time, causing an abrupt change in decay slope. The fraction of the burst that consistent with the external shock model is independent of the observational epochs in the rest frame of GRBs. Moreover, no cases can be explained by the cooling frequency crossing the X-ray or optical band.

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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