伽玛暴(Gamma-Ray Burst)笔记。记录有关伽玛暴的新文章,另外也包括看的老文章、自己的想法、以及跟天文相关的一些东西。 Feel free to leave me a message by comments or by email.

星期一, 七月 11, 2011

Margutti 2011 短暴的X射线耀发

主要内容:
有几个短暴也有X-ray flares.

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文章信息:

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· arXiv e-print (arXiv:1107.1740)
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Title:
X-ray flare candidates in short gamma-ray bursts
Authors:
Margutti, R.Chincarini, G.Granot, J.Guidorzi, C.Berger, E.Bernardini, M. G.Gehrels, N.;Soderberg, A. M.Stamatikos, M.Zaninoni, E.
Publication:
eprint arXiv:1107.1740
Publication Date:
07/2011
Origin:
ARXIV
Keywords:
Astrophysics - High Energy Astrophysical Phenomena
Comment:
19 pages, 16 figures, MNRAS accepted
Bibliographic Code:
2011arXiv1107.1740M

Abstract

We present the first systematic study of X-ray flare candidates in short gamma-ray bursts (SGRBs) exploiting the large 6-year Swift database with the aim to constrain the physical nature of such fluctuations. We find that flare candidates appear in different types of SGRB host galaxy environments and show no clear correlation with the X-ray afterglow lifetime; flare candidates are detected both in SGRBs with a bright extended emission in the soft gamma-rays and in SGRBs which do not show such component. We furthermore show that SGRB X-ray flare candidates only partially share the set of observational properties of long GRB (LGRB) flares. In particular,the main parameter driving the duration evolution of X-ray variability episodes in both classes is found to be the elapsed time from the explosion, with very limited dependence on the different progenitors, environments, central engine life-times, prompt variability time-scales and energy budgets. On the contrary, SGRB flare candidates significantly differ from LGRB flares in terms of peak luminosity, isotropic energy, flare-to-prompt luminosity ratio and relative variability flux. However, these differences disappear when the central engine time-scales and energy budget are accounted for, suggesting that (i) flare candidates and prompt pulses in SGRBs likely have a common origin; (ii) similar dissipation and/or emission mechanisms are responsible for the prompt and flare emission in long and short GRBs, with SGRBs being less energetic albeit faster evolving versions of the long class. Finally, we show that in strict analogy to the SGRB prompt emission, flares candidates fall off the lag-luminosity relation defined by LGRBs, thus strengthening the SGRB flare-prompt pulse connection.
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