Phase-averaged spectrum and one phase-resolved spectrum (phase C, as defined in Fig. 3, displaced by factor of 2 for visualization). The black histogram gives the best-fitting model: an absorbed cutoff power law with iron component at ∼6.5 keV. Green points show background of FPM A. Arrows indicate the location of the reported CRSFs (Doroshenko et al. 2015; D’Aì et al. 2015). The iron line asymmetry is due to the convolution with the detector response and the logarithmic scale. All tested continuum models describe the data comparably well.