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arXiv 1706.00601astro-ph.HE
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GRB 111209 A的光学/近红外余辉:复杂但并非前所未有

The Optical/NIR afterglow of GRB 111209A: Complex yet not Unprecedented

D. A. Kann, P. Schady, F. Olivares E., S. Klose, A. Rossi, D. A. Perley, B. Zhang, T. Krühler, J. Greiner, A. Nicuesa Guelbenzu, J. Elliott, F. Knust, Z. Cano, … 展开作者

D. A. Kann, P. Schady, F. Olivares E., S. Klose, A. Rossi, D. A. Perley, B. Zhang, T. Krühler, J. Greiner, A. Nicuesa Guelbenzu, J. Elliott, F. Knust, Z. Cano, R. Filgas, E. Pian, P. Mazzali, J. P. U. Fynbo, G. Leloudas, P. M. J. Afonso, C. Delvaux, J. F. Graham, A. Rau, S. Schmidl, S. Schulze, M. Tanga, A. C. Updike, K. Varela

摘要:

伽马射线暴(GRB)的余辉在最基本的模型中是简单的,但可以显示出许多复杂的特征。超长持续时间的GRB 111209 A是迄今为止探测到的最长的GRB之一,也是这类罕见GRB中监测到的余辉最好的。我们想解决的问题是,GRB 111209 A是否是一个特殊的事件,超出了它的极端持续时间,以及它是一个经典的GRB还是另一种高能瞬变。余辉可能会提供重要的线索。我们目前的余辉光度学获得的七个波段的GROND成像仪,以及在进一步的七个波段的UVOT望远镜上的尼尔Gehrels斯威夫特天文台。光变曲线的分析,多波段建模和联合拟合与幂律和破碎的幂律,我们使用同期的GROND数据来研究光谱能量分布的演变。我们比较了光学余辉,我们在早期的作品中分析了一个大的合奏,特别是另一个超长的事件,GRB 130925 A。此外,我们还对宿主星系进行了测光研究。我们发现一个强大的,彩色的再增亮事件在大约0.8天后的伽玛暴,在此期间的光谱斜率变得更红。在此之后,光变曲线无色衰减,有证据表明在触发后约9天出现断裂。余辉光度被发现是不例外的。我们发现,双喷流模型能够解释色重亮。余辉特征在其他事件中也被发现过,并且不是唯一的。除持续时间外,GRB 111209 A的瞬发辐射和余辉参数与已知的这些参数的分布一致。虽然这一事件的中心引擎可能与经典的GRB不同,但有多条证据指向GRB 111209 A是由一颗大质量恒星的核心坍缩产生的。

英文摘要:

Afterglows of Gamma-Ray Bursts (GRBs) are simple in the most basic model, but can show many complex features. The ultra-long duration GRB 111209A, one of the longest GRBs ever detected, also has the best-monitored afterglow in this rare class of GRBs. We want to address the question whether GRB 111209A was a special event beyond its extreme duration alone, and whether it is a classical GRB or another kind of high-energy transient. The afterglow may yield significant clues. We present afterglow photometry obtained in seven bands with the GROND imager as well as in further seven bands with the UVOT telescope on-board the Neil Gehrels Swift Observatory. The light curve is analysed by multi-band modelling and joint fitting with power-laws and broken power-laws, and we use the contemporaneous GROND data to study the evolution of the spectral energy distribution. We compare the optical afterglow to a large ensemble we have analysed in earlier works, and especially to that of another ultra-long event, GRB 130925A. We furthermore undertake a photometric study of the host galaxy. We find a strong, chromatic rebrightening event at approx 0.8 days after the GRB, during which the spectral slope becomes redder. After this, the light curve decays achromatically, with evidence for a break at about 9 days after the trigger. The afterglow luminosity is found to not be exceptional. We find that a double-jet model is able to explain the chromatic rebrightening. The afterglow features have been detected in other events and are not unique. The duration aside, the GRB prompt emission and afterglow parameters of GRB 111209A are in agreement with the known distributions for these parameters. While the central engine of this event may differ from that of classical GRBs, there are multiple lines of evidence pointing to GRB 111209A resulting from the core-collapse of a massive star with a stripped envelope.

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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