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Journal Articles The Astrophysical Journal Year : 2012

GRB 110205A: Anatomy of a long gamma-ray burst


The Swift burst GRB 110205A was a very bright burst visible in the Northern hemisphere. GRB 110205A was intrinsically long and very energetic and it occurred in a low-density interstellar medium environment, leading to delayed afterglow emission and a clear temporal separation of the main emitting components: prompt emission, reverse shock, and forward shock. Our observations show several remarkable features of GRB 110205A : the detection of prompt optical emission strongly correlated with the BAT light curve, with no temporal lag between the two ; the absence of correlation of the X-ray emission compared to the optical and high energy gamma-ray ones during the prompt phase ; and a large optical re-brightening after the end of the prompt phase, that we interpret as a signature of the reverse shock. Beyond the pedagogical value offered by the excellent multi-wavelength coverage of a GRB with temporally separated radiating components, we discuss several questions raised by our observations: the nature of the prompt optical emission and the spectral evolution of the prompt emission at high-energies (from 0.5 keV to 150 keV) ; the origin of an X-ray flare at the beginning of the forward shock; and the modeling of the afterglow, including the reverse shock, in the framework of the classical fireball model.

Dates and versions

hal-00685018 , version 1 (03-04-2012)



Bruce Gendre, Jean-Luc Atteia, Michel Boër, François Colas, Alain Klotz, et al.. GRB 110205A: Anatomy of a long gamma-ray burst. The Astrophysical Journal, 2012, 748 (1), pp.article id. 59. ⟨10.1088/0004-637X/748/1/59⟩. ⟨hal-00685018⟩
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