A SEARCH FOR GALACTIC BLACK-HOLE CANDIDATES AT MEV ENERGIES - PRELIMINARY-RESULTS

The COMPTEL instrument on CGRO has surveyed the entire sky in the ener gy range of 0.75-30 MeV. These data provide the first opportunity to p erform a systematic all-sky search for MeV emission from Galactic blac k hole candidates. The COMPTEL team has previously reported on the pos itive detection of both Cyg X-l and GRO J0422+32 at energies up to sim ilar to 2 MeV. The spectrum of Cyg X-1 as measured by COMPTEL suggests that there may exist an additional component other than that produced by Comptonization of thermal electrons. The various possible black ho le emission mechanisms of particular interest in the COMPTEL energy ra nge are described and the status on the search for these emissions fro m all known Galactic black hole candidates is reported.