Mass and environment as drivers of galaxy evolution in SDSS and zCOSMOS and the origin of the Schechter function

Understand

We explore the inter-relationships between mass, star-formation rate and environment in the SDSS, zCOSMOS and other surveys.

• The differential effects of mass and environment are completely separable to z ~ 1, indicating that two distinct processes are operating, "mass-quenching" and "environment-quenching".
• Environment-quenching, at fixed over-density, evidently does not change with epoch to z ~ 1, suggesting that it occurs as large-scale structure develops in the Universe.
• The observed constancy of the mass-function shape for star-forming galaxies, demands that the mass-quenching of galaxies around and above M*, must be proportional to their star-formation rates at all z < 2.