Red sequence and environment: implications for the star formation history in protoclusters

MARTÍNEZ H.J., COENDA, V. & H. MURIEL

Chile

Workshop; Galaxy Clusters in the Early Universe; 2009

ESO

The dependence of the sequence of red galaxies (RS) with theenvironment is investigated using volume limited samples of field, group, and cluster galaxies drawn from the Sloan Digital Sky Survey (SDSS). For a given luminosity, the mean colour of field galaxies is bluer than its group and cluster counterparts. Among systems of galaxies, high mass groups and clusters have the reddest mean colour. Our results are interpreted in terms of the age of the bulk of the stellar population of galaxies, suggesting that the star formation rates of galaxies in protoclusters were significantly higher than their field counterparts.