EGRET all sky map
Credit: Compton Gamma Ray Observatory Team

The Universe at 100 MeV

The Compton Gamma Ray Observatory (CGRO) is the second of NASA's "Great Observatories" (the first being the Hubble Space Telescope). The Energetic Gamma Ray Experiment Telescope (EGRET) provides the highest energy gamma-ray window for CGRO. EGRET's energy range is from 30 million electron volts (30 MeV) to 30 billion electron volts (30 GeV). EGRET is 10 to 20 times larger and more sensitive than previous detectors operating at these high energies and has made detailed observations of high energy processes associated with diffuse gamma-ray emission, gamma-ray bursts, cosmic rays, pulsars, and active galaxies known as gamma-ray blazars. The image above is an all-sky map in Galactic coordinates obtained by EGRET of gamma-ray emission at energies above 100 MeV. The brightest emission is colored yellow in this false-color image, while the faintest emission is blue. The plane of the Milky Way galaxy is clearly seen as a strong source of diffuse and resolved emission. The diffuse emission in the galactic plane is primarily due to cosmic ray interactions with the interstellar medium. The Vela, Geminga, and Crab pulsars are clearly visible as bright knots of emission in the galactic plane in the right portion of the slide. The gamma-ray blazar 3C279 is seen as the brightest knot of emission above the plane. This map was produced by combining EGRET observations from the first year of Compton Observatory operations. More information can be found at the CGRO Science Support Center website.

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Page Author: Dr. Michael F. Corcoran
Last modified November 6, 2001