Scientists Catch Their First Elusive "Dark" Gamma-Ray Burst

For the first time, scientists -- racing the clock -- have snapped a photo of an unusual type of gamma-ray-burst event one minute after the explosion. They captured a particularly fast-fading type of "dark" burst, which comprises about half of all gamma-ray bursts.

A gamma-ray burst announces the birth of a new black hole. It is the most powerful type of explosion known, second only to the Big Bang in total energy release. This latest finding may double the number of gamma-ray bursts available for study and rattle a few theories as well.

These "dark" bursts are so named because they have had no detectable optical afterglow until now. Other bursts have afterglows that linger for days or weeks, likely caused by the explosion's shock waves ramming into and heating gas in the interstellar medium.

The orbiting HETE, which alerts scientists to gamma-ray bursts, spotted one December 11, originating six billion light-years away, and relayed its location to observatories worldwide in 22 seconds. The ground-based RAPTOR (RAPid Telescopes for Optical Response) optical telescope, operated by the Los Alamos National Laboratory in New Mexico, was the first on the scene, observing the afterglow at 65 seconds. Other telescopes rushed to the event in the minutes that followed.

Reports are posted on the publicly accessible Gamma-ray Burst Coordinates Network Web site, operated by NASA's Goddard at: http://gcn.gsfc.nasa.gov/

For the complete article on capturing a gamma-ray burst, go to: http://www.gsfc.nasa.gov/topstory/2002/1223hetegrb.html