Scatter plot of M₂₀₀ against M_∗ for a random subset (one out of 80) of our sample of simulated locally brightest galaxies. Central galaxies are shown as red or blue points according to their g − r colour, using the cuts indicated in Fig. 1. Satellite galaxies are shown as black points. The lower and upper curves give the median and mean values of halo mass as a function of stellar mass.