Title:

What Makes a Gamma-Ray Burst ?



Paul Price
IfA



Abstract:

Gamma-ray bursts (GRBs) were discovered in 1969 by
U.S. satellites deployed to monitor Soviet compliance with
the Nuclear Test Ban Treaty.  For nearly 30 years, their
origin remained clouded in mystery --- at some stages there
were more models than known GRBs!  With the discovery of the
cosmological origin of the long/soft class of GRBs in 1997,
the next question to be answered was, What Makes a Gamma-Ray
Burst?  I will present observations which demonstrate that
the progenitors of long/soft GRBs are massive stars, and
look at the prospects for measuring the cosmic
star-formation history to z > 6 using GRBs.  Finally, I will
show the first detections of short/hard GRBs afterglows
which suggest that this hitherto elusive population are
caused by mergers of compact objects.