Abstract
To shed light on the impact of internal and external quenching mechanisms upon galaxies, in this paper we compare properties of star forming, passive and transition galaxies in three discrete environments: field, groups as representative of intermediate mass systems, and the most massive virialised systems in the Universe, X-ray clusters. We classify galaxies into three sequences: passive (PS), green valley (GV) and star forming (SFS), by means of their UV-optical colour 0.1(NUV-r). We study a number of galaxy properties: UV-optical colour, stellar mass, morphology, specific star formation rate and the history of star formation.
