COMPTEL imaging of the Galactic disk and the separation of diffuse emission and point sources

The rst MeV image of the inner Galaxy obtained with the COMPTEL telescope aboard the Compton Observatory shows a structured ridge of emission along the Galactic equator which probably consists of diiuse radiation and unresolved discrete sources. The intensity distribution of this ridge distinctly diiers from the expected distribution for a simple model of the diiuse radiation. Most remarkable are the observed excursions out of the disk, which may hint at the presence of-ray point sources located several degrees away from the mid-plane, but a diiuse origin cannot be excluded. If these are indeed discrete sources, a substantial fraction of the unresolved emission along the disk may not be of diiuse origin, with an ensemble of sources hidden in the observed ridge.