Gamma-Ray Bursts: Where are we Now?

Abstract

There has been significant progress recently in our understanding of gamma-ray bursts. The long-sought counterparts at other wavelengths have finally been found for a few bursts. In one case, GRB970508, red-shifted absorption lines have been detected, finally settling the debate about the distance scale. The consensus is that the burst sources lie at cosmological distances, requiring at least about 10**51 ergs to be emitted in gamma rays in just a few seconds. Many mysteries remain. There is no consensus on the nature of the sources, although coalescing neutron stars are the leading candidate. I will describe recent GRB observations from a number of satellites, including the Compton Gamma Ray Observatory, the Hubble Space Telescope, and BeppoSAX, as well as ground-based optical and radio observations. I will relate these observations to our present picture of GRBs and describe how future observations might answer the remaining questions. Finally, I will describe how gamma-ray bursts may be able to tell us something about the early Universe.