Corsi 2009 GRB 090510的高能辐射的模型

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测试了几个模型，来拟合观测。

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Title:		High-energy Emission Components in the Short GRB 090510
Authors:		Corsi, Alessandra; Guetta, Dafne; Piro, Luigi
Affiliation:		AA(Università degli studi di Roma "Sapienza" and INFN-Sezione di Roma, Piazzale Aldo Moro 2, 00185 Roma, Italy ; INAF - Istituto di Astrofisica Spaziale e Fisica Cosmica di Roma, Via Fosso del Cavaliere 100, 00133 Roma, Italy ; Current address: LIGO Laboratory, California Institute of Technology, Pasadena, CA 91125, USA; alessandra.corsi@roma1.infn.it ), AB(INAF - Osservatorio Astronomico di Roma, Via Frascati 33, 00040 Monte Porzio Catone, Italy luigi.piro@iasf-roma.inaf.it), AC(INAF - Istituto di Astrofisica Spaziale e Fisica Cosmica di Roma, Via Fosso del Cavaliere 100, 00133 Roma, Italy guetta@oa-roma.inaf.it)
Publication:		The Astrophysical Journal, Volume 720, Issue 2, pp. 1008-1015 (2010). (ApJ Homepage)
Publication Date:		09/2010
Origin:		IOP
ApJ Keywords:		gamma-ray burst: individual: GRB 090510, radiation mechanisms: non-thermal, X-rays: bursts
DOI:		10.1088/0004-637X/720/2/1008
Bibliographic Code:		2010ApJ...720.1008C

Abstract

We investigate the origin of the prompt and delayed emission observed in the short GRB 090510. We use the broadband data to test whether the most popular theoretical models for gamma-ray burst emission can accommodate the observations for this burst. We first attempt to explain the soft-to-hard spectral evolution associated with the delayed onset of a GeV tail with the hypothesis that the prompt burst and the high-energy tail both originate from a single process, namely, synchrotron emission from internal shocks (IS). Considerations on the compactness of the source imply that the high-energy tail should be produced in a late-emitted shell, characterized by a Lorentz factor greater than the one generating the prompt burst. However, in this hypothesis, the predicted evolution of the synchrotron peak frequency does not agree with the observed soft-to-hard evolution. Given the difficulties of a single-mechanism hypothesis, we test two alternative double-component scenarios. In the first, the prompt burst is explained as synchrotron radiation from IS and the high-energy emission (up to about 1 s following the trigger) as IS synchrotron-self-Compton. In the second scenario, in view of its long duration (~100 s), the high-energy tail is decoupled from the prompt burst and has an external shock origin. In this case, we show that a reasonable choice of parameters does indeed exist to accommodate the optical-to-GeV data, provided the Lorentz factor of the shocked shell is sufficiently high. Finally, we attempt to explain the chromatic break observed around ~10³ s with a structured jet model. We find that this might be a viable explanation and that it lowers the high value of the burst energy derived by assuming isotropy, ~10⁵³ erg, below ~10⁴⁹ erg, which is more compatible with the energetics from a binary merger progenitor.

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