Periodogram of ESPRESSO time series. From top to bottom: ESPRESSO RV, ESPRESSO RVs after a simple weighted linear detrending with the BIS-SPAN activity indicator (green), and after removing a Keplerian signal with P = 5.09 days (red), FWHM of the CCF, CONTRAST of the CCF, log(RHK), BIS-SPAN, and the window function. The dashed red vertical lines give the location of the confirmed planet HD 22496 b, the stellar rotation period found by the GP, and its alias. In the two upper panels the dotted horizontal lines give the 0.1 and 1% false alarm probability levels. In the second panel the vertical dotted lines indicate the first ten alias periods of the HD 22496 b signal.