X-ray and γ-ray spectra of Cyg X-1 in the soft state

Authors :: Tadayasu Dotani
Keith Jahoda
Marek Gierlinski
W. Neil Johnson
Ken Ebisawa
Andrzej A. Zdziarski
Source :: AIP Conference Proceedings.
Publication Year :: 1997
Publisher :: AIP, 1997.
Abstract: We present X-ray/gamma-ray observations of Cyg X-1 in the soft state during 1996 May-June. We analyze ASCA, RXTE and OSSE data. The spectrum consists of soft X-ray blackbody emission of an optically thick accretion disk in the vicinity of a black hole and a power law with an energy index alpha around 1.2-1.5 extending to at least several hundred keV. In the spectra, we find the presence of strong Compton reflection, which probably comes from the disk.<br />5 pages, 3 figures, to appear in the Proceedings of 4th Compton Symposium, April 27-30, 1997, Williamsburg, Virginia, USA