Dispersion around the size–luminosity relations for the EFIGI Sérsic and bulge components from Fig. 7. Left: variation of the rms dispersion in the logarithm of the ratio between the actual bulge effective radius R_e and the fitted value R_e, fit as a function of bulge magnitude M_bulge, g around the size–luminosity relation (Eq. (19)) for the Sérsic components and bulges of all types of EFIGI galaxies plotted in the right panel of Fig. 7. The estimated rms dispersion in R_e/R_e, fit increases for fainter bulges, and can be approximated by a linear regression. For comparison, the dispersion around the second-degree fit for the single-Sérsic profile of E galaxies (Eq. (15)), and the linear fits to cD and dE galaxies (Eqs. (17) and (18)) at the mean magnitude of galaxies of each type are shown with different symbols and colors. Right: histogram of R_e/R_e, fit for the Sérsic components and bulges of all types of EFIGI galaxies. In order to account for the increasing dispersion around the fit seen in the left panel, the values of log(R_e/R_e, fit) are divided by the dispersion in the magnitude bin in which they lie, then renormalized to the average over the values for all magnitude intervals.