COMPTEL observations of the Virgo region.
The analysis of all available COMPTEL data collected from the Virgo region of the sky between the beginning of the Compton Gamma-Ray Observatory mission in April 1991 and the end of its observational Phase III in October 1994 is currently in progress. During this period COMPTEL was pointed for in total 15 weeks directly towards the Virgo region of the sky. In the sum of all data, the quasar 3C 273 is detected with a significance of ~9σ in the energy band 1 to 10MeV. There is evidence for the quasar 3C 279 at a significance level of ~3.4σ in the 1-3MeV band. In addition, there are indications for additional (new) MeV γ-ray sources in the Virgo region. The most significant new source was detected at a level of ~4.5σ by COMPTEL in one of the four energy ranges. Another candidate source is spatially consistent with the higher-energy EGRET source 2EG J1224+2155, and reaches a ~3σ significance level at the EGRET source position.
Astronomy and Astrophysics Supplement Series
European Southern Observatory (ESO)
Collmar, W; Bennett, K; Bloemen, H; Blom, J J.; Hermsen, W; Lichti, G G.; McConnell, Mark L.; Morris, D; Schonfelder, V.; Stacy, G; Steinle, H; Strong, A W.; and Williams, O R., "COMPTEL observations of the Virgo region." (1996). Astronomy and Astrophysics Supplement Series. 356.