The prompt-early afterglow connection in GRBs

Author: Robert Mochkovitch, Romain Hascoët and Frédéric Daigne

Abstract: In a recent analysis of 650 Swift X-ray light curves Margutti et al have found correlations linking prompt and early afterglow quantities such asEγ,iso, Lp (luminosity at the end of the plateau phase), tp (duration of the plateau), etc. We discuss how these correlations can be understood in the scenario where the early afterglow of GRBs is made by the reverse shock. We obtain Eγ,iso, Lp and tp for a sequence of synthetic models and compare our results to the Margutti et al data. We find a good agreement if the burst environment is a uniform medium. Wind solutions are also possible but require more extreme values of the model parameters.