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NASA Images Show Gamma Ray Bursts Across Milky Way

By Sindya N. Bhanoo
Washington Post Staff Writer
Wednesday, August 27, 2008;

NASA researchers yesterday released images collected by a new telescope studying high-energy gamma rays. A combined image from 95 hours of the telescope's initial observations showed bursts of gamma rays glowing across the plane of the Milky Way.

The Gamma-Ray Large Area Space Telescope, renamed Fermi, was launched in June and is off to a promising start, NASA scientists said.

"I like to call it our extreme machine," said Jon Morse, the director of astrophysics for NASA. "It will help us crack the mysteries of these enormously powerful emissions."

Gamma rays are powerful light rays invisible to the naked eye. Because Earth's atmosphere absorbs gamma rays, they can be studied only from the outskirts of the universe.

Fermi is gathering data on gamma rays that originate near black holes and high-energy stars called pulsars.

Though much remains unknown, bursts of gamma rays are thought to be emitted from particles coming out of black holes and pulsars, said Peter Michelson, a Stanford physicist and a principal investigator for the mission.

"We don't yet understand the mechanism for how the particles that emit the gamma rays are accelerated," Michelson said. "We're not even sure what the nature of the particles are."

The study is a follow-up on work done by the Energetic Gamma-Ray Experiment Telescope, a mission that studied gamma rays from 1991 to 2000.

Fermi's technology allowed scientists to compile in days what took the first mission one year to do, said Steve Ritz, one of the project's scientists.

The telescope was renamed Fermi yesterday, after Italian physicist Enrico Fermi, because he is "today regarded as one of the top scientists of the 20th century," Ritz said.

The scientists hope that in the five to 10 years that it is in orbit, Fermi will be as remarkable as its namesake.

"This powerful space observatory will explore the most extreme of environments for us," Morse said.