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arXiv 0804.0811astro-ph
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伽马射线暴余辉的早期光学性质

The Early-time Optical Properties of Gamma-Ray Burst Afterglows

A. Melandri, C. G. Mundell, S. Kobayashi, C. Guidorzi, A. Gomboc, I. A. Steele, R. J. Smith, D. Bersier, C. J. Mottram, D. Carter, M. F. Bode, P. T. O'Brien, N.… 展开作者

A. Melandri, C. G. Mundell, S. Kobayashi, C. Guidorzi, A. Gomboc, I. A. Steele, R. J. Smith, D. Bersier, C. J. Mottram, D. Carter, M. F. Bode, P. T. O'Brien, N. R. Tanvir, E. Rol, R. Chapman

摘要:

我们对世界上最大的三台机器人光学望远镜--利物浦望远镜和福克斯望远镜(北望远镜和南望远镜)观测到的63个伽马射线暴进行了多波长分析。在爆发后的第一个10分钟内,检测到24个亮度从R = 10到22 mag的伽玛暴的光发射。通过比较从t = 100秒到大约10^6秒的光学和X射线光变曲线,我们引入了四个主要类别,根据在光学和/或X射线波长处是否存在时间突变来定义。虽然15/24的伽玛暴可以用前向激波模型来模拟,但在标准框架中,即使引入能量注入或环境密度梯度,对其余9个伽玛暴的解释也是非常具有挑战性的。早期的X射线余辉,甚至是由幂律描述的光变曲线的片段,可能是由于中央发动机的额外排放。在我们的样品中,有39个伽玛暴在早期没有被探测到,并且有深的上限(R < 22 mag)。其中只有10个被其他设施识别,主要是在近红外波长,导致暗爆发分数约为50%。由于后期中央引擎活动而导致的早期X射线余辉中的额外发射也可以解释一些黑暗的爆发,因为与光学波段相比,X射线波段的爆发比预期的更亮。

英文摘要:

We present a multiwavelength analysis of 63 Gamma-Ray Bursts observed with the world's three largest robotic optical telescopes, the Liverpool and Faulkes Telescopes (North and South). Optical emission was detected for 24 GRBs with brightnesses ranging from R = 10 to 22 mag in the first 10 minutes after the burst. By comparing optical and X-ray light curves from t = 100 to about 10^6 seconds, we introduce four main classes, defined by the presence or absence of temporal breaks at optical and/or X-ray wavelengths. While 15/24 GRBs can be modelled with the forward-shock model, explanation of the remaining nine is very challenging in the standard framework even with the introduction of energy injection or an ambient density gradient. Early X-ray afterglows, even segments of light curves described by a power-law, may be due to additional emission from the central engine. 39 GRBs in our sample were not detected and have deep upper limits (R < 22 mag) at early time. Of these, only ten were identified by other facilities, primarily at near infrared wavelengths, resulting in a dark burst fraction of about 50%. Additional emission in the early time X-ray afterglow due to late-time central engine activity may also explain some dark bursts by making the bursts brighter than expected in the X-ray band compared to the 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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