Nearby Clusters (WINGS) Distant Clusters (EDisCS) Dwarf galaxies in clusters

Clusters of Galaxies are the largest, gravitationally bound entities in the Universe. They can be tracers of cosmic evolution and of galaxy formation and evolution.

Two specific projects concerning clusters of galaxies carried out at OAPd: WINGS has created a high quality multi-wavelength dataset for galaxies in a large and well-selected sample of nearby clusters and EDisCS has studied the evolution of cluster galaxies and clusters over more than ½ of the Hubble time.

Up to now WINGS has produced integrated and aperture photometry (B,V bands) of ~400,000 galaxies: (U, J, K bands) photometry for a subsample; surface photometry and morphology of ~45,000 galaxies and redshift of ~6,000 galaxies. With these data we analyzed the Fundamental Plane of E-galaxies and we found a strong correlations between the FP coefficients and the local cluster environment (cluster-centric distance and local density). From the analysis of sub-structures in these clusters it is found that the fraction of clusters with substructures (73%) is higher that in most previous studies.

With the EDisCS survey, we have found a correlation between the proportion of star-forming galaxies and the cluster velocity dispersion, pointing at the importance of the cluster mass growth history. We have clarified the relation between star formation activity, morphology and local density, and revealed how the past-starbust frequency depends on environment.

Complementary research on the properties of galaxies in clusters is the study of dwarf galaxies in nearby clusters and the development of automatic tools for the morphological analysis of large data-sets.