Which Factors Shape Galaxy Evolution?

Using samples of isolated and groups galaxies obtained from the first 10000 zCOSMOS-bright high quality redshifts, we study in detail the complex interplay between environment and galaxy evolution. Our main result is that galaxies of log(M(*)/M(circle dot)) approximate to 10.8 do not show any strong environmental dependency up to z similar to 1. In contrast, for masses below this value and at redshift lower than z similar to 1, we witness the emergence of what we call nurture red galaxies: galaxies that slightly deviate from the trend of the downsizing scenario displayed by the global galaxy population and do more so as cosmic time progresses. There are various mechanisms occurring in groups (gradual cessation of star formation induced by gentle gas stripping and starvation by a diffuse intragroup medium, or by slow group-scale harassment), and that are more efficient for less massive galaxies. Our analysis implies that these mechanisms begin to significantly influence galaxy evolution after z similar to 1, a redshift corresponding to the emergence of structures in which these mechanisms take place.