INTERNAL SHOCKS IN A RELATIVISTIC WIND AS A SOURCE FOR GAMMA-RAY BURSTS

We investigate the recent proposal made by Rees and Meszaros (1994) th at GRBs result from internal shocks in the relativistic wind emerging from two coalesced neutron stars. Using a simple model of that wind, w here a large number of layers with different Lorentz factors interact through a series of mildly relativistic shocks we compute the efficien cy of the process and the time profile of the resulting burst. We show that a great variety of profiles can be obtained using plausible init ial distributions of Lorentz factors in the wind. However, the rather low overall efficiency (< 10%) of the process and limits imposed on th e burst duration can be used to put severe constraints on the nature o f the energy source.