A simple non-equilibrium feedback model for galaxy-scale star formation: delayed feedback and SFR scatter

摘要: We explore a class of simple non-equilibrium star formation models within the framework feedback-regulated model ISM, applicable to kiloparsec-scale resolved relations (e.g. Kennicutt–Schmidt). Combining Toomre-Q-dependent local efficiency per free-fall time with for delayed feedback, we are able match normalization and scatter scaling relations. In particular, this suggests that large (∼dex) variations in rates (SFRs) on kiloparsec scales may be due fact supernova feedback is not instantaneous following formation. The SFRs at constant gas surface density galaxy then depends properties when observe its star-forming regions various points throughout their collapse/star ‘cycles’. This has important observational consequences: (1) Kennicutt–Schmidt relation relatively insensitive (small-scale) efficiency; (2) but depletion times velocity dispersions are; (3) sensitive probe time-scale strength; (4) even where ˜Q_(gas) deterministically dictates locally, evolution, variation conditions fractions dynamical times), between galaxies can destroy much observable correlation SFR surveys. Additionally, exhibits low densities, agreement observations flat outer H I disc dispersion profiles.