The afterglows of gamma-ray bursts

摘要

Gamma-ray burst astronomy has undergone a revolution in the last three years, spurred by the discovery of fading long-wavelength counterparts. We now know that at least the long duration GRBs lie at cosmological distances with estiamted electromagnetic energy release of 10~51 - 10~53 erg, making thes te brightest explosions in the Universe. In this article we revew the current observational state of the long-lived "afterglow" emission that accompanies GRBs at X-ray, optical, and radio afterglow wavelengths. We then discuss the insights these observations have given to the progenitor population, the energetics of the GRB events, and the physics of the afterglow emission. We focus particular attention on the evidence linking GRBs to the explosion of massive stars. Throughout, we identify remaining puzzles and ucertainties, and emphasize promising observational tools for addressing them. The imminetn launch of HETE-2, the increasingly sophisticated and coordinated ground-based and space-based observations, and the incereasing availability of 10-m class optical telescopes have primed this field for fantastic growth.