http://www.redorbit.com/news/space/1112823721/mysteries-large-gamma-ray-burst-explained-041613/
April 16, 2013 - redorbit.com
Researchers unwrapped a little more of the mystery surrounding a new
type of powerful cosmic explosion, creating a new theory around the
death of supergiant stars.
These huge explosions create powerful blasts of high energy gamma rays,
known as gamma-ray bursts. These larger blasts can last for several
hours, compared to most gamma-ray bursts which rarely last more than a
minute.
...
Scientists calculated the huge gamma-ray burst using data from the Gemini Observatory
telescope in Hawaii. They determined it sits about halfway between us
and the edge of the observable universe, or roughly 7 billion
light-years away.
...