Theoretical interpretation of the X-ray properties of GRB 960720

Institut d'Astrophysique de Paris, CNRS, 98 bis boulevard Arago, 75014 Paris, France

Send offprint request to: F. Daigne

Received: 29 December 1998
Accepted: 9 March 1999

Abstract

BeppoSAX observations of the single pulse burst GRB 960720 have allowed a detailed study of its X-ray properties: pulse width in different energy bands, spectral evolution from 2 to 700 keV, etc. We show that the early (0-5 s) X-ray emission and the gamma-rays are well explained by internal shocks in a relativistic wind while the late (5-20 s) X-ray emission could come from the reverse shock generated in the wind when it interacts with the external medium. The results for a medium of uniform density are compared to the observations.