Similar to Fig. 2, but for the average photometric magnetic activity. NGC 6811 members are highlighted by the blue circles, whose size indicates the rotation rate: the larger the symbol, the faster the stellar rotation. The gray line corresponds to the smoothed ⟨S​_ph⟩ for the cluster. The semitransparent shaded region marks the T_eff range highlighted in the inset of Fig. 2. The density map represents the reference Kepler sample of field stars.