NASA Plans New Observatory For Gamma Rays
Contact:
Christopher Wanjek
wanjek@gsfc.nasa.gov
301-286-4453February 1, 1999
Greenbelt, Md. -- An international group of astronomers, physicists and engineers will meet at NASA Goddard Space Flight Center on February 9 to formulate plans for the Gamma-Ray Large Area Space Telescope (GLAST), an orbiting observatory designed to explore the most cataclysmic events of the Universe, from the creation of galaxies to the postulated merging of black holes.
This Facility Science Team meeting will provide an update on the project's progress thus far, further define mission science requirements, and discuss technology development in gamma-ray astronomy, often referred to as the astrophysics of extremes.
"Essentially, we are asking what are the main science questions and what's the best way to go about answering them," said Dr. Peter Michelson, Professor of Physics at Stanford University and Co-Chair of the Facility Science Team. "The goal is to understand these most powerful energy sources in the Universe, and GLAST will expand our range of measurements by several orders of magnitude."
A gamma ray is radiation largely produced by high-speed particle collisions, such as from a supernova explosion shooting particles at nearly light speed into interstellar gas. GLAST will measure this most energetic band of electromagnetic radiation from 10 to 300,000 MeV*, comparable to a single telescope measuring from radio, through infrared and optical, and well into X-ray wavelengths.
With such a range, GLAST will detect thousands of active galactic nuclei (AGN), which are thought to harbor supermassive black holes. GLAST will also precisely measure the properties of hundreds of mysterious gamma-ray bursts, recently shown to be the most powerful and distant explosions in the Universe since the Big Bang itself. It is not well understood what causes these bursts, which for a brief moment outshine the entire Universe.
"We are on the threshold of a new era," said Dr. Neil Gehrels, a Goddard-based astronomer and fellow Co-Chair of the Facility Science Team. "GLAST will be to gamma-ray astronomy what Galileo's telescope was to optical astronomy."
GLAST's sensitivity, Dr. Gehrels said, could characterize the 170 unidentified gamma-ray sources documented this year by the Compton Gamma Ray Observatory, perhaps discovering new classes of celestial objects. These unidentified sources made up over half of the catalog's 271 gamma ray sources, demonstrating that the origin of many gamma rays is still a mystery.
"GLAST will be fantastic, giving us magic glasses to see the sky in gamma rays," said Dr. Jonathan Ormes, GLAST Study Scientist and Chief of the Laboratory of High Energy Astrophysics at Goddard. "We will be able to watch an incredible light show caused by the most violent phenomena at the far reaches of the Universe."
Dr. Ormes said GLAST will also contribute to the field of particle physics by examining the possible links between gravity and quantum physics. Explosions from the edge of the visible Universe act as powerful cosmic particle accelerators, producing energies well-beyond the reach of Earth-based accelerators. GLAST will study this process, which could provide a better understanding of fundamental physics as well as promote a host of technological advances and commercial applications.
For more information about GLAST or the meeting, to be held at Goddard in Building 26-205, contact Bill Steigerwald at William.A.Steigerwald@nasa.gov or refer to http://glast.gsfc.nasa.gov.
(*MeV is an energy unit equal to one million eV, or electron volts; the average photon of visible light carries about 2.25 eV.)
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