Title:

The Nature of Short-Hard Gamma-Ray Bursts



Derek Fox
Penn State



Abstract:

I will discuss the revolution in our understanding of short-hard  
gamma-ray bursts that has been provoked by the discovery of the first  
afterglows of these elusive events.  The existence of the short  
bursts as a distinct population was first suggested in 1974, and  
confirmed in 1993.  Until 2005, however, the afterglow revolution  
that revealed the origins of long-duration gamma-ray bursts in the  
deaths of massive stars had passed the short bursts by.  With twelve  
afterglows and multiple redshifts now in-hand, the short bursts are  
revealed as a cosmological phenomenon, like their long-duration  
counterparts. Compared to long bursts, however, short bursts are less  
energetic, lower-redshift explosions produced by a much longer-lived  
progenitor, and lack associated supernovae to very deep limits.  I  
will review the viable models for these cosmic explosions, and derive  
quantitative constraints on the local rate and progenitor lifetimes  
of short bursts by placing the recent events in the context of the  
full BATSE burst catalog (1991-2000).  If the short bursts are  
produced by compact object merger events, these constraints translate  
directly into event rate estimates for LIGO, VIRGO, and future ground- 
based gravitational-wave detectors.