The COMPTEL 1 to 30 MeV all-sky map in continuum gamma radiation represents the results of the first-ever survey of the sky at these energies. The concentration of the emission along the Galactic plane is the most striking aspect of the map. The plane stands out clearly against the rest of the sky indicating that most of the measured gamma-ray fluxes come from regions or objects inside the Galaxy. The dominant Galactic continuum emission seems to come from interstellar space and is visible as diffuse Galactic radiation. Superimposed on the large-scale Galactic emission are point-like sources (like Crab, Vela, Cyg X-1), but many of the Galactic point sources remain unidentified at this time. A significant contribution of unresolved point sources to the apparently diffuse Galactic emission cannot be excluded. At medium and high Galactic latitudes, a few of the gamma-ray blazars, discovered by EGRET, are visible in the COMPTEL map as well. Examples are 3C 273, 3C 279, and PKS 0528+134. The radio galaxy Cen A is also visible at MeV gamma rays. Some of the extragalactic objects detected by COMPTEL are not visible in this map, because they flare up only occasionally: on average they are too weak to be visible in this time-averaged all-sky map.
NASA/COMPTEL team, Max Planck Institute for Extrasolar Physics
circa 1999 <div style="display: none;">date QS:P,+1999-00-00T00:00:00Z/9,P1480,Q5727902</div>
<a rel="nofollow" class="external free" href="https://science.nasa.gov/science-news/science-at-nasa/compton_ast">https://science.nasa.gov/science-news/science-at-nasa/compton_ast</a> (<a rel="nofollow" class="external text" href="https://smd-prod.s3.amazonaws.com/science-pink/s3fs-public/atoms/files/gamma_sky.jpg">image link</a>); text from <a rel="nofollow" class="external free" href="https://heasarc.gsfc.nasa.gov/docs/cgro/epo/posters/Greatest_Hits/COMPTEL_1-30_MeV.html">https://heasarc.gsfc.nasa.gov/docs/cgro/epo/posters/Greatest_Hits/COMPTEL_1-30_MeV.html</a>