X-Ray Observations of CYG X-1 from Salyut 4
Abstract
Prof. D. Ya. Martynov, Director of the Sternberg Astronomical Institute, Moscow, reports that on 1975 June 3 E. Shaffer and E. Moskalenko observed Cyg X-1 with an x-ray telescope on board the space station Salyut 4 from 13h38m UT to 14h20m. From 13h38m the 2-10 keV flux was 0.28 counts/cm**2. In the 0.2-2 keV region the x-ray flux was at the background level of 0.14 counts/cm**2. At 13h54m the 0.2-2 keV flux rose to 0.35 counts/cm**2 and the 2-10 keV flux increased by a factor of 1.9. Large fluctuations were observed in this spectral region with a characteristic time of less than 10s. At 14h10m in the 2-10 keV region a flare was observed lasting about 20s. The maximum flare flux was about 3.9 counts/cm**2. The characteristic rise time of the flare was less than 1s. The observations conform to the model of a disk accretion onto a black hole.
- Publication:
-
International Astronomical Union Circular
- Pub Date:
- June 1975
- Bibcode:
- 1975IAUC.2793....2M