ANS Observations of Cygnus X-1
Abstract
Cygnus X-1 was observed from 3 November until 9 November, 1974, using the hard X-ray (1 28 keV) and soft X-ray (1 8 keV) experiment on board the Astronomical Netherlands Satellite. On three occasions, on 4 and 5 November, the X-ray spectrum was observed to be harder, while the flux intensity in the 1 7 keV ranges decreased by ∼50% from its quiescent value. These events occurred near and following the time of superior conjunction of the likely optical counterpart HDE 226 868. These events appear to be the same as previously reported absorption dips and reveal this phenomenon to be more complex than had been believed. A systematic study of the X-ray spectral variations in these energy bands, on a time scale of 64 seconds over the period of the spectroscopic binary, is presented.
- Publication:
-
Astrophysics and Space Science
- Pub Date:
- June 1976
- DOI:
- 10.1007/BF00645539
- Bibcode:
- 1976Ap&SS..42..175P
- Keywords:
-
- Astronomical Netherlands Satellite;
- Binary Stars;
- Spaceborne Astronomy;
- Stellar Luminosity;
- Stellar Spectra;
- X Ray Stars;
- Astronomical Spectroscopy;
- Light Curve;
- Photon Density;
- Radiant Flux Density;
- Radiation Detectors;
- Satellite Observation;
- Spectral Energy Distribution;
- X Ray Astronomy;
- X Ray Spectra;
- Astrophysics