New results from long-term observations of Cygnus X-1.
Abstract
Observations of Cyg X-1 between October 1974 and July 1975 reveal a persistent 5.6-day modulation of the 3-6 keV X-ray intensity, having a minimum in phase with superior conjunction of the HDE 226868 binary system. The modulation is found to be most pronounced just prior to the April-May 1975 increase of Cyg X-1, after which both the modulation and intensity are at their lowest values for the entire duration of the observations. These data imply that the X-ray emission from Cyg X-1 arises from the compact member of HDE 226868, and that the increase of April-May 1975 may have represented the depletion of accreting material which had not yet been mixed into a cylindrically symmetric accretion disk about the compact member.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- January 1976
- DOI:
- 10.1086/182020
- Bibcode:
- 1976ApJ...203L..63H
- Keywords:
-
- Binary Stars;
- Black Holes (Astronomy);
- X Ray Sources;
- X Ray Stars;
- Crab Nebula;
- Statistical Distributions;
- X Ray Astronomy;
- Astrophysics