The Central Dominant (cD) galaxy in many clusters is significantly more luminous than all the other galaxies, and lies above a simple Schechter function. Special processes are thought to have played a role: higher than normal cannibalism due to the galaxy's central location has added greatly to its mass and luminosity. The example here is the very rich cluster Abell 1689.
Schechter's original (1976) data on 13 clusters, with his function fit. The open circles exclude cD galaxies, while the filled circles include them. The cD galaxies seem anomalously luminous compared to the rest of the sample.