Gamma-Ray Bursts: Accumulating Afterglow Implications, Progenitor Clues, and Prospects
P. Mészáros
Gamma-ray bursts (GRBs) are sudden, intense flashes of
gamma rays that, for a few blinding seconds, light up in an otherwise fairly dark gamma-ray sky. They are detected at the rate of about once
a day, and while they are on, they outshine every other gamma-ray source in the sky, including the sun. Major advances have been made in
the last 3 or 4 years, including the discovery of slowly fading x-ray,
optical, and radio afterglows of GRBs, the identification of host
galaxies at cosmological distances, and evidence showing that many GRBs
are associated with star-forming regions and possibly supernovae.
Progress has been made in understanding how the GRB and afterglow
radiation arises in terms of a relativistic fireball shock model. These
advances have opened new vistas and questions on the nature of the
central engine, the identity of their progenitors, the effects of the
environment, and their possible gravitational wave, cosmic ray, and
neutrino luminosity. The debates on these issues indicate that GRBs
remain among the most mysterious puzzles in astrophysics.
Department of Astronomy and Astrophysics, Pennsylvania State
University, University Park, PA 16803, USA, and Institute for
Theoretical Physics, University of California, Santa Barbara, CA 93106, USA. E-mail: pmeszaros{at}astro.psu.edu
