Top panel: original GLS periodogram of the combined and mean-subtracted RV data (black). The periodogram of the window function (sampling) for the combined data (green) is also shown. Second panel: GLS periodogram after fitting and removing the first detected signal. Third panel: GLS periodogram after fitting and removing both the first and second signals. Bottom panel: GLS periodogram after fitting and removing all three previously detected signals. The blue dotted horizontal lines represents the 0.1% false alarm probability level estimated from 5000 bootstrap resamplings.