New Probe's First Gamma Ray Sky Map Unveiled

Victoria Jaggard
National Geographic News
August 26, 2008

A new map based on early results from the spacecraft formerly known as GLAST is revealing the probe's potential for unraveling some of the most perplexing problems in astrophysics.

The Gamma-ray Large Area Space Telescope was today officially dubbed the Fermi Gamma-ray Space Telescope in honor of Nobel prize-winning physicist Enrico Fermi. The probe was launched into low-Earth orbit on June 11 to scan the heavens for gamma rays, the most energetic wavelengths in the electromagnetic spectrum.

This high-energy radiation comes from a variety of distant and poorly understood cosmic sources, including neutron stars, supermassive black holes, and powerful events known as gamma ray bursts.

The new telescope "will explore the most extreme environments in the universe," Jon Morse, NASA's astrophysics division director, said at a press briefing this afternoon.

Using the craft's first 95 hours of active observation, mission scientists produced a map of gamma ray sources as seen from Earth that shows the same level of detail as previous maps that took more than a year to create.

The new map, which one mission scientist likened to the night sky during a Fourth of July celebration, is "a promise of things to come," noted project scientist Steve Ritz at NASA's Goddard Space Flight Center in Maryland.

It showcases, for example, Fermi's unprecedented field of view, which can image the entire sky in just three hours. This wide scope allows scientists to see gamma ray sources as they flare up and then signal other observatories to follow their progress.

"We have an all-sky alert capability," said Peter Michelson, principal investigator for the probe's large area telescope, who is based at Stanford University in California.

"When one of these things goes off, we see it coming, we see it peak, and we see it go away. That will provide us tremendous insights into the physics of these objects."

Galaxy's Busy Core

The short wavelengths of gamma rays are blocked by Earth's atmosphere, and are so high-energy that they pass right through the lenses in traditional telescopes, making the rays difficult to track.

But based on Einstein's famed equation E=mc2, scientists know that the energy in gamma rays can become matter under the right conditions.

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