Theoretical Interpretation of the Luminosity and Spectral Properties of GRB 031203
Author(s) -
M. G. Bernardini,
C. L. Bianco,
P. Chardonnet,
Federico Fraschetti,
R. Ruffini,
She-Sheng Xue
Publication year - 2005
Publication title -
the astrophysical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.376
H-Index - 489
eISSN - 1538-4357
pISSN - 0004-637X
DOI - 10.1086/498614
Subject(s) - afterglow , physics , gamma ray burst , astrophysics , luminosity , substructure , radiation , baryon , spectral line , thermal , galaxy , astronomy , optics , structural engineering , engineering , meteorology
The X and gamma-ray observations of the source GRB 031203 by INTEGRAL areinterpreted within our theoretical model. In addition to a complete space-timeparametrization of the GRB, we specifically assume that the afterglow emissionoriginates from a thermal spectrum in the co-moving frame of the expandingbaryonic matter shell. By determining the two free parameters of the model andestimating the density and filamentary structure of the ISM, we reproduce theobserved luminosity in the 20-200 keV energy band. As in previous sources, theprompt radiation is shown to coincide with the peak of the afterglow and theluminosity substructure are shown to originate in the filamentary structure ofthe ISM. We predict a clear hard-to-soft behavior in the instantaneous spectra.The time-integrated spectrum over 20 seconds observed by INTEGRAL is wellfitted. Despite this source has been considered "unusual", it appears to us anormal low energetic GRB.Comment: 4 pages, 4 figures, to appear on ApJ Letter
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