First INTEGRAL observations of Cygnus X-3
Goldoni, P.; Westergaard, N. J.; Kretschmar, P.; Hakala, P.; Paizis, A.; Courvoisier, T. J. -L.; Zdziarski, A. A.; Vilhu, O.; Beckmann, V.; Hannikainen, D.; Ebisawa, K.; McCollough, M. L.; Hjalmarsdotter, L.
Switzerland, Finland, Poland, Italy, United States, Germany, France, Denmark
Abstract
We present the first INTEGRAL results on Cyg X-3 from the PV phase observations of the Cygnus region. The source was clearly detected by the JEM-X, ISGRI and SPI. The INTEGRAL observations were supported by simultaneous pointed RXTE/ observations. Their lightcurves folded over the 4.8 hour binary period are compatible with the mean RXTE/ASM and gamma ro/BATSE light curves. We fit our broad-band X-ray/gamma -ray spectra with a physical model, which represents the first such published model for Cyg X-3. The main physical processes in the source are thermal Comptonization and Compton reflection with parameters similar to those found for black-hole binaries at high Eddington rates.
Based on observations with INTEGRAL, an ESA project with instruments and science data center funded by ESA and member states (especially the PI countries: Denmark, France, Germany, Italy, Switzerland, and Spain), the Czech Republic, and Poland and with the participation of Russia and the US.