INTEGRAL-RXTE observations of Cygnus X-1

Date

2003-11-17

Department

Program

Citation of Original Publication

Pottschmidt, K., J. Wilms, M. Chernyakova, M. A. Nowak, J. Rodriguez, A. A. Zdziarski, V. Beckmann, et al. “INTEGRAL-RXTE Observations of Cygnus X-1.” Astronomy & Astrophysics 411, no. 1 (November 1, 2003): L383–88. https://doi.org/10.1051/0004-6361:20031258.

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Attribution 4.0 International (CC BY 4.0)

Subjects

Abstract

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 kT ∼ 50−90 keV and an optical depth of τ ∼ 1.0−1.3 plus reflection from a cold or mildly ionized slab with a covering factor of Ω/2π ∼ 0.2−0.3. 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.