GLS periodogram of the TOI-771 ESPRESSO RVs and activity indicators. The vertical red line marks the possible stellar rotational period at ∼98 days. The vertical red ticks in the RV periodogram mark the peaks at ∼42 d and ∼13 d, which are related to each other, and to the 98-d signal (see Fig. 5). The vertical grey lines show the periods of TOI-771 b (2.33 d), and of the second planet candidate TOI-771 c (∼7.6 d). The 10%, 1%, and 0.1% FAP levels are drawn with horizontal dashed, dash-dotted, and dotted lines, respectively.