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Extreme Universe:Most Extreme Gamma-Ray Blast Ever! February 24, 2009

Posted by jcconwell in Astronomy, Extreme Universe, Gamma Ray Bursts.
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The explosion, designated GRB 080916C, occurred just after midnight GMT on September 16 (7:13 p.m. on the 15th in the eastern US). Two of Fermi’s science instruments — the Large Area Telescope and the Gamma-ray Burst Monitor — simultaneously recorded the event. Together, the two instruments provide a view of the blast’s gamma-ray emission from energies ranging from 3,000 to more than 5 billion times that of visible light.


GRB 080916C's X-ray afterglow appears orange and yellow in this view that merges images from Swift's UltraViolet/Optical and X-ray telescopes. (Image courtesy NASA/Swift/Stefan Immler)

With the greatest total energy, and the highest-energy initial emissions ever before seen, a gamma-ray burst recently observed by the Fermi Gamma-ray Space Telescope set new records. The blast, which also raises new questions about gamma-ray bursts, was discovered by the FGST’s Large Area Telescope, a collaboration among NASA, the U.S. Department of Energy (DOE) Office of Science and international partners.

A team led by Jochen Greiner at the Max Planck Institute for Extraterrestrial Physics in Garching, Germany, established that the blast occurred 12.2 billion light-years away using the Gamma-Ray Burst Optical/Near-Infrared Detector (GROND) on the 2.2-meter (7.2-foot) telescope at the European Southern Observatory in La Silla, Chile.

“Already, this was an exciting burst,” says Julie McEnery, a Fermi deputy project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “But with the GROND team’s distance, it went from exciting to extraordinary.”

FGST team members showed that the blast exceeded the power of nearly 9,000 ordinary supernovae, using a distance of 12.2 billion light-years, and the gas emitting the first gamma rays must have moved at no less than 99.9999 percent the speed of light. This burst’s is the most extreme to date, in both power and speed .