Collapse in Self-gravitating Turbulent Fluids

Daniel W. Murray; Philip Chang; Norman W. Murray; John Pittman

doi:10.1093/mnras/stw2796

paper

Collapse in Self-gravitating Turbulent Fluids

arXiv:1509.05910 · doi:10.1093/mnras/stw2796

Abstract

Motivated by the nonlinear star formation efficiency found in recent numerical simulations by a number of workers, we perform high-resolution adaptive mesh refinement simulations of star formation in self-gravitating turbulently driven gas. As we follow the collapse of this gas, we find that the character of the flow changes at two radii, the disk radius $r_{d}$ , and the radius $r_{*}$ where the enclosed gas mass exceeds the stellar mass. Accretion starts at large scales and works inwards. In line with recent analytical work, we find that the density evolves to a fixed attractor, $ρ (r, t) \to ρ (r)$ , for $r_{d} < r < r_{*}$ ; mass flows through this structure onto a sporadically gravitationally unstable disk, and from thence onto the star. In the bulk of the simulation box we find that the random motions $v_{T} \sim r^{p}$ with $p \sim 0.5$ , in agreement with Larson's size-linewidth relation. In the vicinity of massive star forming regions we find $p \sim 0.2 - 0.3$ , as seen in observations. For $r < r_{*}$ , $v_{T}$ increases inward, with $p = - 1/2$ . Finally, we find that the total stellar mass $M_{*} (t) \sim t^{2}$ in line with previous numerical and analytic work that suggests a nonlinear rate of star formation.

22 pages, 31 figures, Accepted to Monthly Notices of the Royal Astronomical Society

Collapse in Self-gravitating Turbulent Fluids

Abstract

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