Iterative GLS periodogram of the TOI-771 ESPRESSO RVs. The sinusoidal model corresponding to the best frequency is subtracted at each iteration, starting from top to bottom. The vertical red line marks most significant peak in each iteration, and the corresponding frequency and period are reported. The vertical red ticks in the first panel mark the peaks at ∼98 d and ∼13 d, which are related to each other and to the 42-d signal. All three peaks disappear after the first iteration. The 10%, 1%, and 0.1% FAP levels are drawn with horizontal dashed, dashdotted, and dotted lines, respectively.