Super-orbital variability in Cygnus X-1 ISSI, Bern, Switzerland March 3-7, 2008 J. Poutanen, A. Zdziarski, A. Ibragimov MNRAS, submitted

Accretion via Roche lobe and focused wind Stream trajectory and disk formation for the case of equal masses. Coriolis force shifts the stream from the line connecting the stars.

Superorbital variability Radio X-rays

Dips distribution

Orbital profiles as a function of superorbital phase

(c) A view from the top bulge  b disc supergiant  =0.5  =0

i    =0.5  =0 observer (a) A view along the orbital plane,  =0 bulge  supergiant  black hole disc  =0.5  =0

 =0.5  =0 observer (b) A view along the orbital plane,  =0.5 disc supergiant black hole bulge  =0.5  =0

Model Wind Parameters: inclination i=40 deg Precession angle  Bulge Optical depths: bulge b,0 , wind w,0 Bulge azimuth b

Model Emissivity profile of the accretion disk For the jet/ outflow

Orbital profiles as a function of superorbital phase

Results

PDS of the model flux

Conclusions Discovery of orbital modulation strength on superorbital phase of Cyg X-1 Effect can be explained by the bulge displaced from the line connecting the stars by 25 deg. Distribution of dips is consistent with the model Beat-frequencies should be observed, with the stronger lower one.

Log-normal flux distribution