Peculiarities in the orbital and precessional variability of SS433 from INTEGRAL observations

Understand

Based on multiyear INTEGRAL observations of SS433, a composite IBIS/ISGRI 18-60 keV orbital light curve is constructed around zero precessional phase $\psi_{pr}= 0$.

• It shows a peculiar shape characterized by a significant excess near the orbital phase $\phi_{orb}= 0.25$, which is not seen in the softer 2-10 keV energy band.
• Such a shape is likely to be due to a complex asymmetric structure of the funnel in a supercritical accretion disk in SS433.
• The orbital light curve at 40-60 keV demonstrates two almost equal bumps at phases $\sim 0.25$ and $\sim 0.75$, most likely due to nutation effects of the accretion disk.