Top: EPIC PN light curve in the energy range 0.3−12.0 keV for observation C. The double-peak pulse profile is clearly visible. Bottom: phase-energy diagram for the EPIC PN data obtained by binning the source counts into energy and rotational phase channels, then normalizing to the phase-averaged energy spectrum for the same observation (same as in Fig. 2, but not normalized to the energy-integrated pulse profile). The four phase bins used for the phase-resolved spectroscopy on the EPIC spectrum are identified by the green bars and numbers.