NONUNIVERSAL STAR FORMATION EFFICIENCY IN TURBULENT ISM

ABSTRACT We present a study of a star formation prescription in which star formation efficiency (SFE) depends on local gas density and turbulent velocity dispersion, as suggested by direct simulations of SF in turbulent giant molecular clouds (GMCs). We test the model using a simulation of an isolat...

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Bibliographic Details
Published in:The Astrophysical journal 2016-08, Vol.826 (2), p.200-200
Main Authors: Semenov, Vadim A., Kravtsov, Andrey V., Gnedin, Nickolay Y.
Format: Article
Language:English
Subjects:
ASTRONOMY AND ASTROPHYSICS
Computer simulation
Density
Efficiency
Galaxies
galaxies: ISM
Mathematical models
methods: numerical
numerical
Star formation
stars: formation
Turbulence
Turbulent flow
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Summary:ABSTRACT We present a study of a star formation prescription in which star formation efficiency (SFE) depends on local gas density and turbulent velocity dispersion, as suggested by direct simulations of SF in turbulent giant molecular clouds (GMCs). We test the model using a simulation of an isolated Milky-Way-sized galaxy with a self-consistent treatment of turbulence on unresolved scales. We show that this prescription predicts a wide variation of local SFE per free-fall time, ∼ 0.1%-10%, and gas depletion time, ∼ 0.1-10 Gyr. In addition, it predicts an effective density threshold for star formation due to suppression of in warm diffuse gas stabilized by thermal pressure. We show that the model predicts star formation rates (SFRs) in agreement with observations from the scales of individual star-forming regions to the kiloparsec scales. This agreement is nontrivial, as the model was not tuned in any way and the predicted SFRs on all scales are determined by the distribution of the GMC-scale densities and turbulent velocities in the cold gas within the galaxy, which is shaped by galactic dynamics. The broad agreement of the star formation prescription calibrated in the GMC-scale simulations with observations both gives credence to such simulations and promises to put star formation modeling in galaxy formation simulations on a much firmer theoretical footing.
ISSN:0004-637X
1538-4357
1538-4357
DOI:10.3847/0004-637X/826/2/200