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When Feedback Fails: The Scaling and Saturation of Star Formation Efficiency

Grudić, Michael Y. and Hopkins, Philip F. and Faucher-Giguère, Claude-André and Quataert, Eliot and Murray, Norman and Kereš, Dušan (2018) When Feedback Fails: The Scaling and Saturation of Star Formation Efficiency. Monthly Notices of the Royal Astronomical Society, 475 (3). pp. 3511-3528. ISSN 0035-8711.

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We present a suite of 3D multiphysics MHD simulations following star formation in isolated turbulent molecular gas discs ranging from 5 to 500 parsecs in radius. These simulations are designed to survey the range of surface densities between those typical of Milky Way giant molecular clouds (GMCs) (∼10^2M⊙pc^(−2)) and extreme ultraluminous infrared galaxy environments (∼10^4M⊙pc^(−2)) so as to map out the scaling of the cloud-scale star formation efficiency (SFE) between these two regimes. The simulations include prescriptions for supernova, stellar wind, and radiative feedback, which we find to be essential in determining both the instantaneous per-freefall (ε_(ff)) and integrated (ε_(int)) star formation efficiencies. In all simulations, the gas discs form stars until a critical stellar surface density has been reached and the remaining gas is blown out by stellar feedback. We find that surface density is a good predictor of ε_(int), as suggested by analytic force balance arguments from previous works. SFE eventually saturates to ∼1 at high surface density. We also find a proportional relationship between ε_(ff) and ε_(int), implying that star formation is feedback-moderated even over very short time-scales in isolated clouds. These results have implications for star formation in galactic discs, the nature and fate of nuclear starbursts, and the formation of bound star clusters. The scaling of ε_(ff) with surface density is not consistent with the notion that ε_(ff) is always ∼ 1 per cent on the scale of GMCs, but our predictions recover the ∼ 1 per cent value for GMC parameters similar to those found in spiral galaxies, including our own.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Hopkins, Philip F.0000-0003-3729-1684
Faucher-Giguère, Claude-André0000-0002-4900-6628
Quataert, Eliot0000-0001-9185-5044
Kereš, Dušan0000-0002-1666-7067
Additional Information:© 2018 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2018 January 3. Received 2017 December 3; in original form 2016 December 16. Published: 08 January 2018. We thank Neal J. Evans II, Eve Ostriker, Dávid Guszejnov, Chris Hayward, Matthew Orr and Andrew Wetzel for helpful comments and critique. We also thank the anonymous referees for highly comprehensive and helpful feedback that motivated a more thorough understanding of our results. Support for PFH and MYG was provided by an Alfred P. Sloan Research Fellowship, NASA ATP Grant NNX14AH35G and NSF Collaborative Research Grant #1411920 and CAREER grant #1455342. Numerical calculations were run on the Caltech computer cluster ‘Zwicky’ (NSF MRI award #PHY-0960291) and allocation TG-AST130039 granted by the Extreme Science and Engineering Discovery Environment (XSEDE) supported by the NSF.
Group:TAPIR, Astronomy Department
Funding AgencyGrant Number
Alfred P. Sloan FoundationUNSPECIFIED
Subject Keywords:galaxies: active – galaxies: nuclei – galaxies: starburst – galaxies: star clusters: general – galaxies: star formation
Issue or Number:3
Record Number:CaltechAUTHORS:20170601-125207516
Persistent URL:
Official Citation:Michael Y Grudić, Philip F Hopkins, Claude-André Faucher-Giguère, Eliot Quataert, Norman Murray, Dušan Kereš; When feedback fails: the scaling and saturation of star formation efficiency, Monthly Notices of the Royal Astronomical Society, Volume 475, Issue 3, 11 April 2018, Pages 3511–3528,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:77891
Deposited By: Ruth Sustaita
Deposited On:01 Jun 2017 20:51
Last Modified:09 Mar 2020 13:18

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