Visual summary of the analysis results. The blue circles represent the results obtained with the epoch-folding approach, and the results obtained with the Lomb-Scargle technique are shown as orange squares. The data sets are Swift, MAXI, ISGRI, MAXI hardness ratio, and spin-frequency derivative evolution, as indicated by the labels in the figure. The solid red line indicates the 1160.8 d radial velocity period obtained by Hinkle et al. (2006), and the dashed lines mark the corresponding 12.4 d uncertainty on this value.