Swift/BAT light curve (15–50 keV) with a bin size equal to the 12.67 d orbital period. Tick marks on the segments located above the light curve denote the times of the Swift/XRT pointing observations (green), as well as the optical/IR photometric data from the ground-based telescopes ROTSEIIId (orange), IAC80 (blue), and TCS (red). The optical spectroscopic observations come from OSN (purple), NOT (yellow), and RTT150 (light red) (see also Table 2).