INTEGRAL & RXTE Power Spectra of Cygnus X-1

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.

arXiv comment7 pages, 4 figures, to appear in Proc. 35rd Cospar Scientific Assembly, accepted by Advances in Space Research

References in corpus (6)

• ISGRI: the INTEGRAL Soft Gamma-Ray Imager
• RXTE Observation of Cygnus X-1: II. Timing Analysis
• Soft state of Cygnus X-1: stable disk and unstable corona
• Long Term Variability of Cyg X-1 I. X-ray spectral-temporal correlations in the hard state
• Long Term Variability of Cygnus X-1. IV. Spectral Evolution 1999-2004
• A close look at the state transitions of Galactic black hole transients during outburst decay

Cited by in corpus (5)

• Long term variability of Cygnus X-1: VI. Energy-resolved X-ray variability 1999-2011
• Probing the temporal variability of Cygnus X-1 into the soft state
• The INTEGRAL view on Black Hole X-ray Binaries
• The X-ray Power Spectral Density Function of the Seyfert Active Galactic Nucleus NGC 7469
• Long term variability of Cygnus X-1. VIII. A spectral-timing look at low energies with NICER