Phase-resolved results for RX J0440. Left: aligned light curves (in gray) of the triggers in Table 1 – one highlighted in black for clarity. Horizontal bars correspond to the segments used for the phase-resolved analysis. Orange bars represent segments in phase used to produce the right panels. Right: periodograms of RX J0440 data at different spin phases, corresponding to segments 1 and 4, as indicated on top. Symbols are as in Fig. 3. The segment 1 panel shows the periodogram resulting from data outside of the pulse profile peak, when the periodogram does not require a second Lorentzian component. The segment 4 panel shows the periodogram obtained from pulse-profile peak-centered data, where a second Lorentzian component is required at ~0.2 Hz.