Dr. Andrew Fruchter (STScI) visit our group and give colloquium speech

Nov 20, 2009

“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 most of these bursts, the so-called long, soft bursts, are produced by the collapse of extremely massive stars 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.  Even if uncertainties surrounding their formation and emission mechanisms remain, both types of bursts may prove useful cosmological probes in the years ahead.