EXOSAT Observations of CYGNUS-X-1 - Study of the Soft X-Ray Excess
Abstract
Ten observations of Cygnus X-1 made by the EXOSAT medium energy experiments in the period of 1984 to 1985 when the source was in its low state are examined. The presence of a soft component (black body temperature of around 0.2 keV) on top of the high energy power law component is confirmed in all spectra. The emission line at 6.2 keV is also visible and its intensity varies during the dips. The soft component undergoes more distinct fluctuations than the hard one, which is well seen on a color-color and a color-intensity diagram. The results are discussed in the framework of an accretion disc model.
- Publication:
-
Two Topics in X-Ray Astronomy, Volume 1: X Ray Binaries. Volume 2: AGN and the X Ray Background
- Pub Date:
- November 1989
- Bibcode:
- 1989ESASP.296..269B
- Keywords:
-
- Black Holes (Astronomy);
- Cygnus Constellation;
- X Ray Astronomy;
- X Ray Binaries;
- Accretion Disks;
- Black Body Radiation;
- Color-Color Diagram;
- Emission Spectra;
- Exosat Satellite;
- Power Spectra;
- Stellar Models;
- Stellar Spectra;
- Astronomy