Time series (left column) and GLS periodograms (right column) of the HARPS activity indicators, namely ${\mathrm{R}}_{\mathrm{H}\mathrm{K}}^{\mathrm{\prime }}$, H_α, Na D1, and Na D2. On the right, the horizontal dotted red lines mark the 0.1% false alarm probability (FAP). The shaded areas in yellow, orange, and red mark the rotation frequency f_rot, and its first and second harmonics (2f_rot and 3f_rot), along with their 1σ intervals. The transit frequencies f_b, f_c, and f_d of the three planets are marked with vertical blue dotted lines.