The imaging Compton telescope COMPTEL aboard NASA's Compton Gamma-Ray Observatory has opened the MeV gamma-ray band as a new window to astronomy. COMPTEL provided the first complete all-sky survey at MeV energies and produced the first all-sky maps.
COMPTEL has demonstrated that the sky is rich in phenomena that can be studied at these energies. A variety of gamma-ray emitting objects are visible either in continuum or line emission. Among the continuum sources are spin-down pulsars, stellar black hole candidates, supernova remnants, interstellar clouds, nuclei of active galaxies, gamma-ray bursters, and the Sun during solar flares. Line detections from supernova remnants have been made in the light of the 1.809 MeV 26Al line, the 1.156 MeV 44Ti line, and the 847 and 1.238 keV 56Co lines. In addition, possible evidence for the detection of interstellar nuclear interaction lines from exited 12C and 16O nuclei has been found.
COMPTEL has also measured the diffuse interstellar and cosmic gamma radiation, whose properties are described elsewhere (1,2). For the identification of galactic sources, a modelling of the diffuse galactic emission is essential. Such a modelling at this time does not yet exist at the required degree of accuracy.
The present catalogue is restricted to all those sources that have been definitely detected so far, and provides upper limits to the MeV flux from different types of objects. A second COMPTEL source catalogue will be produced after a detailed and accurate modelling of the diffuse interstellar emission has become possible.
|Type of Source|| Number of
|Spin-Down Pulsars||4 + 2 (?)||Crab, Vela, PSR 1951+32, PSR 1509-58, Geminga (?), PSR 0656+14 (?)|
|Galactic Sources | b | < 10°||5||Crab Nebula, Cyg X-1, Nova Persei, GRO J 2227+61 (2 CG 106+1.5), GRO J 0241+6119 (2 CG 135+01)|
|Active Galactic Nuclei||10||(e.g. 3C 273, 3C 279, PKS 0528+134, Cen A); most are time variable|
|Unidentified high-latitude Sources||5||2 of the 5 sources show extended emission and may have to do with HVC complexes|
|Gamma-Ray Line Sources||6||SN 1991T, Cas A, Vela, Cygnus, Carina, Orion; the inner Galaxy (-30 < l < +30) shows extended 1.8 MeV line emission|
|Gamma-Ray Burst Sources within COMPTEL field-of-view||29||Location error radii vary from 0.68° to 5.58° (mean error radius: 2.26°)|
Also available in postscript format.