The Impact of cold gas accretion above a mass floor on galaxy scaling relations

Understand

Using the cosmological baryonic accretion rate and normal star formation efficiencies, we present a very simple model for star-forming galaxies (SFGs) that accounts for the mass and redshift dependencies of the SFR-Mass and Tully-Fisher relations from z=2 to the present.

• The time evolution follows from the fact that each modelled galaxy approaches a steady state where the SFR follows the (net) cold gas accretion rate.
• The key feature of the model is a halo mass floor M_{min}~10^{11} below which accretion is quenched in order to simultaneously account for the observed slopes of the SFR-Mass and Tully-Fischer relations.
• The same successes cannot be achieved via a star-formation threshold (or delay) nor by varying the SF efficiency or the feedback efficiency.