Broadband PDS of the persistent light curve corresponding to different luminosity levels during the second outburst decay and the first mini-outburst. The red line corresponds to the luminosity of L = 5.0 × 10³⁸ erg s⁻¹, the green dashed line to L = 7.6 × 10³⁷ erg s⁻¹, blue dot dashed to L = 2.5 × 10³⁷ erg s⁻¹. The dotted line is from the mini-outburst at luminosity L = 8.8 × 10³⁷ erg s⁻¹. The PDS were logarithmically rebinned with respect to frequency to suppress the noise at the highest frequencies. The dominating regular pulsations are visible around 2 Hz. QPO features are seen around 20, 40 and 60 Hz. A PDS component between 5 and 200 Hz is referred to as the high-frequency bump. Note that the Miyamoto normalization was used, rebinning at lower luminosity seemingly shifts the pulse frequency and error bars were left out for clarity.