Description
Recent observational studies find that the star formation efficiency (SFE) per free-fall time varies both within and between galaxies. This strongly implies that galactic star formation (SF) might have additional physical dependencies beyond that on the gas mass/density implied by the Schmidt-Kennicutt relation. Yet this relation is often used to model SF in (cosmological-scale) simulations, missing out on nuanced differences that will affect each galaxy’s evolution due to the complex interplay between SF and feedback.
I will present detailed analysis of galaxies drawn from cosmological simulations, featuring different SF models: contrasting a constant SFE with one that takes into account the environmental dependence on the turbulent properties of the gas (which can successfully explain the observed star formation rate (SFR) of the Milky Way and the suppressed SFR in gas-hosting, early-type galaxies).
I will show that despite broadly similar stellar masses, the SFRs and SF histories differ significantly between the galaxies evolved with the different SF models. The gas properties (e.g. dense gas fraction, amount of fragmentation/interstellar medium (ISM) morphology) and thus the galaxies’ positions on scaling relations are distinctly different as well; a direct consequence of the different SFEs leading to SF in different ISM conditions, thus affecting the impact of the subsequent stellar feedback and further evolution of the galaxy. These results present an important step towards a better understanding of the physics of SF and the impact these small-scale processes have on galaxy evolution across cosmic time.
