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INTEGRAL & RXTE Power Spectra of Cygnus X-1

K. Pottschmidt·J. Wilms·M. A. Nowak·S. Larsson·A. A. Zdziarski·G. G. Pooley
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Abstract

We evaluate 0.03-20 Hz power spectra of the bright black hole binary Cyg X-1 obtained from non-deconvolved INTEGRAL-ISGRI event data. The ISGRI power spectra are compared to contemporary RXTE-PCA ones in the same hard X-ray energy band of 15-70 keV. They agree well in shape. Since the ISGRI power spectrum of Cyg X-1 is not background corrected it lies about an order of magnitude below the PCA values. In 2003 a soft outburst of Cyg X-1 occurred. From the RXTE-ASM and Ryle radio long term lightcurves and the RXTE spectra we see a canonical ``hard state -- intermediate state -- soft state'' evolution. We discuss the evolution of the power spectra in the 15-70 keV range which so far is much less well studied than that at softer energies. We interpret our results regarding the origin of certain variability components.

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K. Pottschmidt, J. Wilms, M. A. Nowak, S. Larsson, A. A. Zdziarski, G. G. Pooley. 2005-04-18. INTEGRAL & RXTE Power Spectra of Cygnus X-1. https://doi.org/10.1016/j.asr.2005.04.032

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