Physical parameters of IRGs as a function of L_IR. a) Absolute magnitude M_r; b) (u − r) color; c) stellar mass M_star; and d) velocity dispersion σ. Filled circles are median values of each bin, and error bars indicate the dispersion of the data; e) AGN fraction (Seyferts, LINERs and composite galaxies). We show only 30% of IRGs in the plot, but median values and AGN fraction are computed using the whole IRG sample.