Wednesday, April 17, 2013

Dying Supergiant Stars Implicated in Hours-Long Gamma-Ray Bursts

http://www.sciencedaily.com/releases/2013/04/130416180032.htm

April 16, 2013 - ScienceDaily.com
Three unusually long-lasting stellar explosions discovered by NASA's Swift satellite represent a previously unrecognized class of gamma-ray bursts (GRBs). Two international teams of astronomers studying these events conclude that they likely arose from the catastrophic death of supergiant stars hundreds of times larger than the sun.
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Using the Gemini North Telescope in Hawaii, Levan and his team obtained a spectrum of the faint galaxy that hosted the Christmas burst. This enabled the scientists to identify emission lines of oxygen and hydrogen and determine how much these lines were displaced to lower energies compared to their appearance in a laboratory. This difference, known to astronomers as a redshift, places the burst some 7 billion light-years away.
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Scientists Unravel The Mysteries Of Large Gamma-Ray Bursts

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.
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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.
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