2005ApJ...621..291C

This paper presents all-sky maps of diffuse gamma radiation in various energy ranges between 30 MeV and 10 GeV, based on data collected by the EGRET instrument on the Compton Gamma Ray Observatory (CGRO). Although the maps can be used for a variety of applications, the immediate goal is the generation of diffuse gamma-ray maps, which can be used as a diffuse background/foreground for point-source analysis of the data to be obtained from new high-energy gamma-ray missions such as GLAST and AGILE. To generate the diffuse gamma maps from the raw EGRET maps, the point sources in the Third EGRET Catalog were subtracted out using the appropriate point-spread function for each energy range. After that, smoothing was performed to minimize the effects of photon statistical noise. A smoothing length of 1° was used for the Galactic plane maps. For the all-sky maps, a procedure was used that resulted in a smoothing length roughly equivalent to 4°. The result of this work is 16 maps of different energy intervals for|b|≤20° and 32 all-sky maps, 16 in equatorial coordinates (J2000.0) and 16 in Galactic coordinates.