Georg Weidenspointner, Martin Varendorff and the COMPTEL collaboration
A large number of possible origins for the CDG have been proposed, attributing the CDG to either a truly diffuse origin or to the emission of unresolved point sources or both. Over the last years significant progress has been made in the determination of the energy spectrum of the CDG. A multiwavelength spectrum of the CDG from X-rays through g-rays is depicted in Fig. 1. Recent analyses indicate that the CDG is most likely composed of a number of different components, each dominating a different energy range [1997a].
The COMPTEL energy range from 0.8-30 MeV is of particular interest. At lower and higher energies the CDG seems to be dominated by emission from unresolved Seyfert galaxies and Blazars, respectively [1997a], but the situation is still unclear in the transition region covered by COMPTEL. A preliminary spectrum of the CDG was measured with COMPTEL by Kappadath et al. . Recently, this measurement was refined above 9 MeV [1997b].
P. Sreekumar et al., The Extragalactic Diffuse Gamma-Ray
S.C. Kappadath et al., The preliminary cosmic diffuse g-ray spectrum from 800 keV to 30 MeV measured with COMPTEL, 1996
S.C. Kappadath et al., The Total Cosmic Diffuse Gamma-Ray Spectrum from 9 to 30 MeV Measured with COMPTEL, 1997b