Regulation of star formation by large scale gravito-turbulence

Adi Nusser; Joseph Silk

doi:10.1093/mnras/stab3121

paper

Regulation of star formation by large scale gravito-turbulence

arXiv:2110.13922 · doi:10.1093/mnras/stab3121

Abstract

A simple model for star formation based on supernova (SN) feedback and gravitational heating via the collapse of perturbations in gravitationally unstable disks reproduces the Schmidt-Kennicutt relation between the star formation rate (SFR) per unit area, $Σ_{S F R}$ , and the gas surface density, $Σ_{g}$ , remarkably well. The gas velocity dispersion, $σ_{g}$ , is derived self-consistently in conjunction with $Σ_{S F R}$ and is found to match the observations. Gravitational instability triggers {"gravito-turbulence"} at the scale of the least stable perturbation mode, boosting $σ_{g}$ at $Σ_{g} > Σ_{g}^{thr} = 50 M_{⊙} pc^{- 2}$ , and contributing to the pressure needed to carry the disk weight vertically. $Σ_{S F R}$ is reduced to the observed level at $Σ_{g} > Σ_{g}^{thr}$ , whereas at lower surface densities, SN feedback is the prevailing energy source. Our proposed star formation recipes require efficiencies of order 1\%, and the Toomre parameter, $Q$ , for the joint gaseous and stellar disk is predicted to be close to the critical value for marginal stability for $Σ_{g} < Σ_{g}^{thr}$ , spreading to lower values and larger gas velocity dispersion at higher $Σ_{g}$ .

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Regulation of star formation by large scale gravito-turbulence

Abstract

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