The zCOSMOS Redshift Survey: How group environment alters global downsizing trends

Understand

We took advantage of the wealth of information provided by the first ~10000 galaxies of the zCOSMOS-bright survey and its group catalogue to study the complex interplay between group environment and galaxy properties.

• The classical indicator F_blue (fraction of blue galaxies) proved to be a simple but powerful diagnostic tool.
• We studied its variation for different luminosity and mass selected galaxy samples.
• Using rest-frame B-band selected samples, the groups galaxy population exhibits significant blueing as redshift increases, but maintains a lower F_blue with respect both to the global and the isolated galaxy population.