Abstract

On Aug. 5, 1992, BATSE detected the bright soft X-ray transient GRO J0422+32,also known as Nova Per 1992. The COMPTEL instrument (0.75-30MeV) aboard the Compton Gamma-Ray Observatory (CGRO) observed this black-hole candidate twice. During the first observation, which started when the X-ray flux was at its maximum, GRO J0422+32 was detected between 1 and 2MeV. The flux in this energy range was higher than expected from an extrapolation of the standard Sunyaev-Titarchuk Comptonisation model fits to the contemporaneous OSSE and SIGMA data. We discuss several models that may explain the total hard-X/γ-ray spectrum, including the generalised Comptonisation model from Titarchuk. During the second observation, 3 weeks later, no evidence for emission above 1MeV was seen.

Department

Physics

Publication Date

4-1995

Journal Title

Astronomy and Astrophysics

Publisher

European Southern Observatory (ESO)

Document Type

Article

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