The Variable Superorbital Modulation of Cygnus X-1

Superorbital variability of X-ray and radio emission of Cyg X-1 – II. Dependence of the orbital modulation on the superorbital phase

We discover a pronounced dependence of the strength of the soft X-ray orbital modulation in Cyg X-1 in the hard state on its superorbital phase. We find our results can be well modelled as orbital-phase dependent X-ray absorption in an accretion bulge, located at the accretion disc edge close to the companion but displaced from the line connecting the stars by about 25◦ and in the case when the...

Superorbital variability of X-ray and radio emission of Cyg X-1 – II. Dependence of the orbital modulation and spectral hardness on the superorbital phase

We discover a pronounced dependence of the strength of the soft X-ray orbital modulation and the spectral hardness in Cyg X-1 in the hard state on its superorbital phase. We find our results can be well modelled as a combination of two effects: the precession of the accretion disc (which appears to cause the superorbital flux modulation) and the orbital-phase dependent X-ray absorption in an ac...

Variable X-ray Absorption in High-mass X-ray Binaries Cygnus X-1 and Vela X-1 Abstract Variable X-ray Absorption in High-mass X-ray Binaries Cygnus X-1 and Vela X-1

Variable X-ray Absorption in High-Mass X-ray Binaries Cygnus X-1 and Vela X-1

Orbital Modulation of X-rays from Cygnus X-1 in Its Hard and Soft States

We have analyzed over 2 yr of RXT E/All-Sky Monitor data for Cygnus X-1. We have detected the 5.6 day orbital period in Lomb-Scargle periodograms of both light curves and hardness ratios when Cyg X-1 was in the hard state. This detection was made with improved sensitivity and temporal coverage compared with previous detections by other X-ray missions. The folded light curves and hardness ratios...

The X-ray Corona and Jet of Cygnus X-1