Institut für Astronomie und Astrophysik

Abteilung Astronomie

Preprint Ka/98

RXTE Observations of Cygnus X-1 - Broad-Band Spectra and High-Resolution Timing

K. Pottschmidt(1), J. Wilms(1), M.A. Nowak(2), J.B. Dove(3), M.C. Begelman(2), R. Staubert(1)

(1)Institut für Astronomie und Astrophysik, Astronomie, Universität Tübingen, Waldhäuser Str. 64, D-72076 Tübingen, Germany
(2)JILA, University of Colorado, Boulder, CO 80309-440, U.S.A.
(3)CASA, University of Colorado, Boulder, CO 80309-389, U.S.A.

1999, Highlights in X-ray Astronomy, ed. B. Aschenbach, MPE Report, in press

Abstract. We present results from a 20 ksec RXTE observation of the black hole candidate Cyg X-1. We apply self-consistent accretion disk corona models to these hard state data and show that Comptonization in a spherical corona irradiated by soft photons from an exterior cold disk is able to successfully model the spectrum. We also present the power spectrum, the coherence function, and the time lags for lightcurves from four energy bands. By modeling the high-resolution lightcurves with stochastic linear state space models, we show that the rapid hard state variability of Cyg X-1 can be explained with a single timescale.

Key words: -

Paper (73k gzip'ed Postscript including figures)

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Jürgen Barnstedt (barnstedt AT astro.uni-tuebingen.de) Last updated 16-Nov-1998