Astronomy and Astrophysics – Astrophysics
Scientific paper
2002-10-23
Mon.Not.Roy.Astron.Soc. 345 (2003) 854
Astronomy and Astrophysics
Astrophysics
12 pages, accepted to MNRAS
Scientific paper
10.1046/j.1365-8711.2003.07004.x
The specific incidence of radio flares appears to be significantly larger than that of the prompt optical emission. This abundance, coupled with the reverse shock interpretation suggests that radio flares add a unique probe on the physics of GRB shocks. Motivated thus, we estimate the strength of the reverse shock expected for bursts in which multi-wavelength observations have allowed the physical parameters of the forward shock to be determined. We use all 6 bursts (980519, 990123, 990510, 991208, 991216, 000418) which are found to be adiabatic and thus predicted to have a strong reverse shock. We aim to constrain the hydrodynamic evolution of the reverse shock and the initial bulk Lorentz factor -- which we found to be between $10^{2}$ and $10^{3}$ and well above the lower limits derived from the requirement that gamma-ray bursts be optically thin to high-energy photons. In half of the cases we improve the description of the early afterglow lightcurves by adding a contribution from the reverse shock. Modelling of this early emission provides the opportunity to investigate the immediate surroundings of the burst. For 991216 and 991208, the expected $1/r^2$ density structure for a stellar wind is not compatible with the early afterglow lightcurves. Considering the radial range relevant to these GRBs, we discuss the conditions under which the inclusion of a wind termination shock may resolve the absence of a $1/r^2$ density profile.
Ramirez-Ruiz Enrico
Soderberg Alicia Margarita
No associations
LandOfFree
Flaring up: radio diagnostics of the kinematic, hydrodynamic and environmental properties of GRBs does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Flaring up: radio diagnostics of the kinematic, hydrodynamic and environmental properties of GRBs, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Flaring up: radio diagnostics of the kinematic, hydrodynamic and environmental properties of GRBs will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-162844