The public lecture will be presented by Prof. Pawan Kumar on Sat.,
Feb. 4 at 1 p.m. at the Applied Computational Engineering & Sciences
(ACES) Bldg., Rm. 2.302 just following our Board of Visitors'
Meeting. We invite you to this special lecture. Please encourage
others to attend.

Pawan's talk title and abstract are as follows:

The unraveling of powerful cosmic explosions

Bright flashes of radiation (gamma-rays and x-rays) are observed at
Earth once or twice a day. These flashes come from a random part of
the sky and appear randomly during the day or night. These events
(explosions) typically last for a few seconds. However, during this
brief time an enormous amount of energy comes out -- the energy
release in these explosions in a few seconds is comparable to the
total energy output of the Sun over its entire lifetime of about 10
billion years. For several decades after their discovery, little was
known as to where in the universe these explosions are occurring. And
we didn't know anything about what kind of an object is exploding and
why. However, in the last two or three years the mystery of these
cosmic explosions has rapidly unraveled, and we now know that some of
these events are associated with deaths of massive stars and some
others with colliding neutron stars. It is almost certain that we are
"seeing" black holes being born in these violent explosions.
Observations of these events, called Gamma-ray Bursts or GRBs for
short, by the recently launched NASA satellite - Swift - and the
follow up observations using optical, radio and x-ray telescopes have
greatly advanced our understanding of these enigmatic explosions. I
will describe some recent observations and discuss what we have
learned about these explosions from them.