Rotation period P_rot as a function of the mean large spacing Δν for RGs displaying both rotational modulation and oscillations. The gray line indicates the critical period T_crit and the red line a rotational velocity of 80% of T_crit. Blue squares are the RGs with clear rotational modulation, blue circles those with low S/N detection. Orange symbols indicate the same for those with crowding factor less than 0.98. This figure echoes Fig. 4 of Ceillier et al. (2017).