We present first results from contemporaneous observations of Cygnus X-1 with INTEGRAL and RXTE, made during INTEGRAL's performance verification phase in 2002 November and December. Consistent with earlier results, the 3-250 keV data are well described by Comptonization spectra from a Compton corona with a temperature of kTsimilar to50-90 keV and an optical depth of tausimilar to1.0-1.3 plus reflection from a cold or mildly ionized slab with a covering factor of Omega/2pisimilar to0.2-0.3. A soft excess below 10 keV, interpreted as emission from the accretion disk, is seen to decrease during the 1.5 months spanned by our observations. Our results indicate a remarkable consistency among the independently calibrated detectors, with the remaining issues being mainly related to the flux calibration of INTEGRAL.
|Journal||Astronomy & Astrophysics|
|Publication status||Published - 2003|
- gamma rays : observations
- stars : individual : Cyg X-1
- black hole physics
- X-rays : general
- X-rays : binaries