  Gamma-ray bursts (GRB) are sudden, intense flashes of gamma-rays which, 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 three or four years, including the
discovery of slowly fading x-ray, optical and radio afterglows of GRBs, the
identification of host galaxies at cosmological distances, and finding evidence
for many of them being 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 GRB remain among the most mysterious
puzzles in astrophysics.

Astrophysics