The Meaning and Consequences of Star Formation Criteria in Galaxy Models with Resolved Stellar Feedback

Understand

We consider the effects of different star formation criteria on galactic scales, in high-resolution simulations with explicitly resolved GMCs and stellar feedback.

• We compare: (1) a self-gravity criterion (based on the local virial parameter and the assumption that self-gravitating gas collapses to high density in a free-fall time), (2) a fixed density threshold, (3) a molecular-gas law, (4) a temperature threshold, (5) a Jeans-instability requirement, (6) a criteria that cooling times be shorter than dynamical times, and (7) a convergent-flow criterion.
• We consider these both MW-like and high-density (starburst) galaxies.
• With feedback present, all models produce identical integrated star formation rates (SFRs), in agreement with the Kennicutt relation.