Environmental and morphological dependence of the luminosity function of galaxies

In this paper we analyze the environmental and morphological dependence of the galaxy luminosity function (LF) by using a sample of homogeneous observational data: the Updated Zwicky Catalog ( UZC). This sample is used to study the type-specific luminosity function of galaxies in the local field as well as in various environments which cover from isolated galaxies to moderately rich clusters. We show that the overall LF cannot always be explained as a composition, taking into account the relative abundance of Hubble types, of type-dependent luminosity functions (LFT) with universal shapes. The environment, characterized by its richness r, also plays a crucial role in the shape of the specific LF for each Hubble type T. Nevertheless, the r and T dependence appears to be weak enough to allow for the definition of nearly universal luminosity functions, Phi( r; T) with coarse-grained bins on both r and T.