Central versus effective stellar mass density. The central stellar mass density calculated within 1 kpc radius (Σ_{1 kpc}) is plotted as a function of the effective stellar mass density (Σ_Re). Blue filled squares are field ellipticals in the GOODS-S regions, red filled circles are cluster ellipticals. Cyan crosses are elliptical galaxies from CANDELS.Errorbars are not shown to observe the agreement among the different samples and the relationship between the quantities.