Nicuesa Guelbenzu, A. 2012 GRB090510的晚期余辉观测

主要内容:


精彩摘抄:

X射线和UVOT的观测。从拐折的时间上来看，很有可能第一个拐折是jet break，而第二个是频率穿过，穿过之后二者的时间指数就一样了，因为它们在同一个频率段。文章中并没有提到这个。

光学余辉



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Title:		The late-time afterglow of the extremely energetic short burst GRB 090510 revisited
Authors:		Nicuesa Guelbenzu, A.; Klose, S.; Kruehler, T.; Greiner, J.; Rossi, A.; Kann, D. A.; Olivares E., F.; Rau, A.; Afonso, P. M. J.;Elliott, J.; Filgas, R.; Kuepcue Yoldas, A.; McBreen, S.; Nardini, M.; Schady, P.; Schmidl, S.; Sudilovsky, V.; Updike, A. C.;Yoldas, A.
Publication:		eprint arXiv:1201.3885
Publication Date:		01/2012
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		submitted to Astronomy & Astrophysics, accepted for publication on Dec 24, 2011
Bibliographic Code:		2012arXiv1201.3885N

Abstract

The discovery of the short GRB 090510 has raised considerable attention mainly because it had a bright optical afterglow and it is among the most energetic events detected so far within the entire GRB population. The afterglow was observed with swift/UVOT and swift/XRT and evidence of a jet break around 1.5 ks after the burst has been reported in the literature, implying that after this break the optical and X-ray light curve should fade with the same decay slope. As noted by several authors, the post-break decay slope seen in the UVOT data is much shallower than the steep decay in the X-ray band, pointing to an excess of optical flux at late times. We reduced and analyzed new afterglow light-curve data obtained with the multichannel imager GROND. Based on the densely sampled data set obtained with GROND, we find that the optical afterglow of GRB 090510 did indeed enter a steep decay phase starting around 22 ks after the burst. During this time the GROND optical light curve is achromatic, and its slope is identical to the slope of the X-ray data. In combination with the UVOT data this implies that a second break must have occurred in the optical light curve around 22 ks post burst, which, however, has no obvious counterpart in the X-ray band, contradicting the interpretation that this could be another jet break. The GROND data provide the missing piece of evidence that the optical afterglow of GRB 090510 did follow a post-jet break evolution at late times.

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