Precessing And Wobbling Accretion Disk in X-Ray Pulsar Her X-1 In M. N. Pavlinsky ART-XC Telescope Observations

We present the results of observation of LMXBs Her X-1 by the Pavlinsky ART-XC telescope onboard the Spectrum-Roentgen-Gamma(SRG) observatory in the 4-25 keV energy band near the moment of the main turn-on. The orbital phase of opening the X-ray source by accretion disk was determined φb ≈ 0.25. The direct observational evidence of the nutation of the bend incline precessing accretion disk in the Her X-1 system with the period of 0.87 days was retrieved from the analysis of the X-ray flux variability. The pulsations in the X-ray emission was detected at orbital phase φb ≈ 0.77 in the nutational variations of the flux before the main turn-on.