Gamma-ray bursts: a mystery being unraveled

Pawan Kumar (U of Texas, Austin) - Apr 25 at 12:00 noon

Flashes of radiation in gamma-rays are observed once or twice a day originating from some random part of the sky (and random in time). These events (explosions) typically last for less than a minute. During this time the energy radiated in gamma-rays is of order 10^{51} erg or the kinetic energy release in a typical supernova explosion but about two orders of magnitude larger than the EM-radiation from a supernova in a month. Multi-wavelength observations of radiation we receive following Gamma-ray bursts have greatly advanced our understanding of these enigmatic explosions. For instance, we now know that gamma-ray bursts are highly beamed and relativistic explosions. In the last few years we have seen a number of compelling lines of evidence that at least a certain fraction of gamma-ray bursts are associated with the death of massive stars. I will describe recent observations from Swift and discuss what we have learned about these bursts.

The seminar will be held in 544 Campbell Hall.


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