Lomb-Scargle periodograms of the SOPHIE radial velocities of HIP 65407. Upper panel: periodogram computed from the radial velocities with all fits. The second and third panels show the periodograms computed from the residuals of the fits that only include HIP 65407b or HIP 65407c, respectively. Bottom panel: periodogram after subtracting the two-planet fit. The two vertical dotted lines show the periods of the two planets. The horizontal dashed lines correspond to the false-alarm probability of 1 × 10^-3.