Observations of Cygnus X-1 in its two intensity states by ANS.
Abstract
The hard X-ray experiment (1 - 28 keV) on ANS, observed Cygnus X-1 in November 1974, and in May 1975, putting in evidence the two dramatically different states of this object. The average intensity in November was 15 cts/sec, and the observations showed remarkable features in the X-ray light curve and in the spectrum, which were correlated with the 5.6 days period of HDE226868. The May observations showed a count rate of approximately 80-100 cts/sec, with fluctuations up to approximately 130 cts/sec, uncorrelated with the spectroscopic binary. The May X-ray spectrum was much softer than the November one, and possibly was made up of two components.
- Publication:
-
NASA Special Publication
- Pub Date:
- 1976
- Bibcode:
- 1976NASSP.389..429P
- Keywords:
-
- Cygnus Constellation;
- X Rays;
- Binary Stars;
- Conferences;
- Spectrum Analysis;
- Stellar Spectra;
- Astronomy