Left: surface brightness profile I(R) for Sérsic models with different values of m, focussing on models with small m. In this and all of the following figures, we work in dimensionless units, or equivalently, we consider a model with R_e = L = M = 1. Middle: luminosity density profile ν(r) for the same set of models. Right: luminosity profiles of models with m ⩽ 1, but now shown in linear scale instead of log-log scale. All model with are characterised by a central depression.