Comparative analysis of the properties of bright early-type galaxies in nearby clusters and in the field

We compare the kinematic, photometric and spectro-photometric properties of a complete, volume limited sample of early-type galaxies in the Virgo and Fornax clusters with a field sample composed of two subsets: galaxies with interaction signatures and non-interacting, mormal' objects. Cluster and field galaxies show remarkable differences in the mu(e) - log R -e plane. While field early-type galaxies populate the entire Kormendy's re lation, Virgo and Fornax galaxies show a marked gap between bright and ordi nary cluster members. This seems specific to the cluster environment. In th e field we further find evidence of bright galaxies with a very low effecti ve surface brightness which are totally absent in clusters. They could repr esent a transient phase during interactions. The relation between the expon ent of the Sersic's law, m, and log R-e is valid, with similar slope and di spersion, both for field and for cluster galaxies. Bright galaxies in the f ield tend to have, on the average, larger (V/sigma)* values than cluster me mbers and to show a larger dispersion in the (B - R)(e) color. Differences in the kappa-space and D-n - sigma representations of the Funda mental Plane between interacting and/or post interacting objects and cluste r galaxies are also visible. Dependencies of the residuals from the Fundame ntal Plane are also discussed as function of several parameters. We find si gnificant correlations of the residuals with Mg-2 and Delta 4000 indices. We suggest that the above differences could be explained in a framework in which the evolution of bright early-type galaxies in cluster has been Froze n by the cluster dynamic evolution while very effective encounters/mergers control the evolution in the field where "rejuvenated" early-type galaxies could be found.