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Strange new blast of gamma rays reveals new way to destroy stars

Astronomers have observed a previously unrecognized type of long-lasting gamma ray burst (GRB), according to Andrew Levan, an astronomer at the University of Warwick, in Coventry, England.

Three such bursts have been discovered between 2010 and 2012, and one of these, GRB 111209A, is of particular interest to scientists. Astronomers say the gamma ray burst in question is the longest ever observed, with a duration of approximately 25,000 seconds, or about 7 hours.

“We have observed the longest gamma ray burst in modern history, and think this event is caused by the death of a blue supergiant,” said lead researcher Bruce Gendre, who led the study while at the Italian Space Agency’s Science Data Center in Frascati, Italy. “It caused the most powerful stellar explosion in recent history, and likely since the Big Bang occurred.”

Long-duration gamma ray bursts are a type of stellar explosion that results from the collapse of supermassive stars. The explosions are some of the brightest and most powerful electromagnetic events in the universe. All GRBs emit power jets of ejecta, that propel matter in opposite directions at speeds approaching the speed of light, and the blasts emit surges of gamma rays and X-rays, producing afterglows that can be observed with optical and radio equipment.

Using NASA’s Swift telescope, the European Space Agency’s XMM-Newton satellite, and other international space telescopes, Gendre and his colleagues have been able to study GRB 111209A, since its eruption on Dec. 9, 2011. The 7-hour long burst is much longer than any previously observed.

Astronomers have traditionally recognized two types of GRBs: short and long, based on the duration of the gamma-ray signal. Short bursts last two seconds or less and are thought to represent a merger of compact objects in a binary system, with the most likely suspects being neutron stars and black holes. Long GRBs may last anywhere from several seconds to several minutes, with typical durations falling between 20 and 50 seconds. These events are thought to be associated with the collapse of a star many times the Sun’s mass and the resulting birth of a new black hole.

The astronomers discussed their findings Tuesday at the 2013 Huntsville Gamma-ray Burst Symposium in Nashville, Tennessee, a meeting sponsored in part by the University of Alabama at Huntsville and NASA’s Swift and Fermi Gamma-ray Space Telescope missions. Gendre’s findings appear in the March 20 edition of The Astrophysical Journal.

Delila James

Delila James

Staff Writer
Delila James practiced civil rights and employment law for almost 20 years. Before going to law school, she raised organic lamb on a ranch in the Sierra Nevada foothills, ran a dairy farm in Muscoda, WI, and then owned a popular live music nightclub in Madison, WI. She has a Master's degree in the History of Science from the University of Wisconsin-Madison, where she went to law school. She also is a published poet. She now is a book editor, writes legal blogs, and is trying to finish a book. She has been writing for Science Recorder since March, 2013.
About Delila James (1065 Articles)
Delila James practiced civil rights and employment law for almost 20 years. Before going to law school, she raised organic lamb on a ranch in the Sierra Nevada foothills, ran a dairy farm in Muscoda, WI, and then owned a popular live music nightclub in Madison, WI. She has a Master's degree in the History of Science from the University of Wisconsin-Madison, where she went to law school. She also is a published poet. She now is a book editor, writes legal blogs, and is trying to finish a book. She has been writing for Science Recorder since March, 2013.