Generalized Lomb-Scargle periodograms of the SOPHIE RVs, activity indicators, and window function of the three seasons of RV observations: , , and . The vertical color lines mark the P_rot at 34.4d in yellow, the first harmonic at P_rot/2 in light blue, and the time range of differential rotation in light green between P_eq = 32.0 d and P_pol = 45.5 days. The black horizontal lines indicate the FAP levels of 10% (solid), 1% (dashed), and 0.1% (dotted).