1996A&AS..120C..13S

The Imaging Compton Telescope (COMPTEL) aboard NASA's Compton Gamma-Ray Observatory has opened the 1 to 30MeV γ-ray energy range as a new window to astronomy. The first-ever broadband all-sky maps in this energy range now exist. A variety of γ-ray emitting objects are visible, namely spin-down pulsars, stellar black-hole candidates, supernova remnants, extended regions of interstellar space, nuclei of active galaxies, γ-ray bursts, and the Sun during solar flares. Moreover, the MeV range is rich in γ-ray lines. Here, COMPTEL has achieved a major breakthrough by generating the first all-sky map of the 1.8MeV line from radioactive ²⁶Al. In addition, COMPTEL succeeded in the first detection of the 1.156MeV line from radioactive ⁴⁴Ti from a supernova remnant (Cas A), and - again for the first time - detected MeV emission from the Orion complex that can be ascribed to nuclear interaction lines from excited ¹²C and ¹⁶O nuclei. Recently, indications of two ⁵⁶Co lines at 847 and 1.238MeV were found in the measurement of SN 1991T.