May 11, 1998: For one or two seconds on December 14, 1997, a remote gamma ray source was "as luminous as the rest of the entire universe," according to Caltech professor George Djorgovski.
The burst was detected by the Italian/Dutch satellite BeppoSAX and NASA’s Compton Gamma Ray Observatory satellite. Cameras aboard BeppoSAX recorded the x-ray afterglow of the gamma ray burst, thereby providing a relatively accurate location for the source.
Astronomers then located a fading optical counterpart to the x-ray source. Using the 10-meter Keck telescope, Djorgovski and Caltech colleague Shrinivas Kulkarni observed the emission spectrum of an extremely faint galaxy at that location and found a red shift of z = 3.4. That places the gamma ray source at a distance of about 12 billion light years--most of the way back to the big bang.
From the distance and the observed brightness of the burst, astronomers calculate that, in a matter of seconds, the energy released during the burst was hundreds of times that produced by a supernova explosion and about equal to the energy radiated by our entire galaxy over a period of several centuries.
Finding such a large energy release over such a brief period of time is unprecedented in astromy, except for the Big Bang itself. "In a region about a hundred miles across, the burst created conditions like those in the early universe, about one millisecond after the Big Bang," said Djorgosvoski.
Gamma ray bursts occur at a frequency of about one per day at random locations in space. How they are generated is unknown. A collision between neutron stars is one mechanism that has been postulated.
Sources: NASA/Caltech Press Release.
Gamma blast from way, way back. Science 280:514, April 24, 1998.