Distribution of stars showing rotational modulation in the P_rot–Δν space. Open grey dots correspond to the 151 stars discarded according to the crowding criterion. Filled magenta dots are the 19 stars removed according to the T_crit criterion. Blue dots represent stars for which a reliable rotation period has been derived (361 stars). The grey line indicates the critical period T_crit and the red line marks a rotational velocity of 80% of the critical value. The open square symbols indicate RGB stars with depressed dipolar modes following Stello et al. (2016b), while star symbols indicate stars with normal dipolar modes.