2.19.2009

Gamma Ray Blast Tantalizes
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So much for the Afterglow. NASA image shows
orange and yellow globules of light, merging images from
Swift's UltraViolet/Optical and X-ray telescopes.


Billions and billions of light years away....in fact 12.2 billion, according to calculations prepared by Joachen Greiner's team at the Max Planck Institute for Extraterrestrial Physics, which used the GROND (Gamma-Ray burst Optical/Near-Infrared Detector) on a mountain top in Chile.

It is the largest gamma-ray explosion ever recorded, an estimated 3,000 times to 5 billion times the intensity of visible light. Detected in September in the constellation Carina, Latin for ship's keel, which is immediately contiguous with the constellations Puppis (the poop deck) and Vela (the sails) in the Southern Hemisphere. Claudius Ptolemy listed these three components together as Argo Navis, in his first century sky catalog. A report is appearing from SLAC through Eureka Alert, based on work done by NASA's Fermi telescope, GROND, and SLAC.

"If you think about it in terms of energy, X-rays are more energetic because they penetrate matter. These things don't stop for anything -- they just bore through and that's why we can see them from enormous distances," astronomer Frank Reddy of NASA said.

"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."

"Burst emissions at these energies are still poorly understood, and Fermi is giving us the tools to figure them out," added Large Area Telescope Principal Investigator Peter Michelson, a Stanford University physics professor affiliated with the Department of Energy's SLAC National Accelerator Laboratory.

In an interesting coincidence, the star Eta Carinae, only 7,500 light years away in our own galaxy, has been flagged as the most potent nearby gamma-ray threat for Earth, and was the source of a false-supernova scare in 1843. At 100 solar masses, it is regarded as a young, unpredictable, and risky star, prone to starbursts.


Image courtesy of Chandra X-Ray Observatory and Hubble ST

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