Recent COMPTEL Observations of Cygnus X-1

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Session 55 -- SN 1993J; High Energy Astrophysics
Oral presentation, Wednesday, 10:30-12:00, Dwinelle 145 Room

[55.06] Recent COMPTEL Observations of Cygnus X-1

M. McConnell, A. Connors, D. Forrest, J. Ryan (UNH), W. Collmar, V. Sch\"onfelder, H. Steinle, A. Strong (MPE), R. van Dijk, W. Hermsen (SRON-Leiden), K. Bennett (SSD/ESA)

The COMPTEL experiment on the {\sl Compton Gamma-Ray Observatory} (GRO) images gamma radiation in the 0.75-30 MeV energy range. Since its launch in April of 1991, COMPTEL has observed the Cygnus region on four separate ocassions. These data provide unprecedented sensitivity for the energy range just above 1 MeV. Using these data, we have studied the emission from Cygnus X-1 to search for any evidence of excess flux beyond that expected from an extrapolation of the hard X-ray spectrum. Data collected by COMPTEL during 1991 showed clear evidence for emission from Cygnus X-1 extending up to $\sim$2 MeV. Although variability between the observations in June and August of 1991 was observed, there was no evidence for any excess emission in the region near 1 MeV. Here we shall report on the first results from data collected by COMPTEL during December, 1992 and March, 1993. These results will be discussed in the context of previous observations at these energies, including the earlier COMPTEL observations.

Wednesday program listing