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High-energy Emission Components in the Short GRB 090510

Corsi, Alessandra and Guetta, Dafne and Piro, Luigi (2010) High-energy Emission Components in the Short GRB 090510. Astrophysical Journal, 720 (2). pp. 1008-1015. ISSN 0004-637X. http://resolver.caltech.edu/CaltechAUTHORS:20100928-133554737

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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 ~10^3 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, ~10^(53) erg, below ~10^(49) erg, which is more compatible with the energetics from a binary merger progenitor.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1088/0004-637X/720/2/1008DOIUNSPECIFIED
http://iopscience.iop.org/0004-637X/720/2/1008PublisherUNSPECIFIED
Additional Information:© 2010. The American Astronomical Society. All rights reserved. Received 2009 November 23; accepted 2010 July 13; published 2010 August 16. The authors are grateful to Patrick Sutton for helping improve the manuscript by carefully proofreading its final version. A.C. thanks the Italian L’Oréal-UNESCO program “For Women in Science,” and EGO—European Gravitational Wave Observatory, for support. The authors also acknowledge the support of ASI-INAF contract I/088/06/0.
Group:TAPIR
Funders:
Funding AgencyGrant Number
ASI-INAFI/088/06/0
Subject Keywords:gamma-ray burst: individual (GRB 090510); radiation mechanisms: non-thermal; X-rays: bursts
Classification Code:PACS: 98.70.Rz; 95.30.Gv; 95.30.Cq
Record Number:CaltechAUTHORS:20100928-133554737
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20100928-133554737
Official Citation:Alessandra Corsi et al 2010 ApJ 720 1008 doi: 10.1088/0004-637X/720/2/1008
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:20200
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:28 Sep 2010 22:56
Last Modified:26 Dec 2012 12:28

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