THE COMA CLUSTER LUMINOSITY FUNCTION

Based on a new spectroscopic sample (nearly) complete to a magnitude b (26.5)=18.0, we have derived the luminosity function for the central r egion of the Coma cluster. We find that a single Schechter function do es not provide a good fit to the magnitude distribution up to b(26.5)= 20.0, and a superposition of a Gaussian and a Schechter function is re quired. A possible interpretation of this result is the existence of t wo different populations of early-type galaxies in the cluster, one of them being affected by evolutionary processes specific to the cluster environment. This interpretation will be tested on our new photometri c sample of Coma duster galaxies, which is complete to a magnitude V s imilar or equal to 22.