Andy Fruchter (STScI)

Andy Fruchter Colloquium - Cancelled

ATNF Marsfield Lecture Theatre

Abstract

This colloquium is cancelled because of illness.

Gamma-Ray Bursts from a Safe Distance

Gamma-Ray Bursts are explosions of nearly unrivalled brilliance. They
can be bright enough to be seen at cosmological distances with the
naked eye and can appear to emit the energy of the rest mass of the
sun in high-energy photons in a matter of seconds. I will show
evidence that the most populous subgroup of bursts, the so-called
long, soft bursts, are produced by the collapse of extremely massive
stars typically in galaxies unlike our own, but similar in many ways
to our neighbors, the Magellanic clouds. The astrophysical origin
of a smaller subset of bursts, the short, hard bursts, remains a
mystery, though these seem to be distributed much more like the
general population of stars in the local universe than are the long
bursts. Even if uncertainties surrounding their formation and
emission mechanisms remain, both types of bursts may prove useful
cosmological probes in the years ahead.