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Stellar feedback sets the universal acceleration scale in galaxies

Grudić, Michael Y. and Boylan-Kolchin, Michael and Faucher-Giguère, Claude-André and Hopkins, Philip F. (2020) Stellar feedback sets the universal acceleration scale in galaxies. Monthly Notices of the Royal Astronomical Society: Letters, 496 (1). L127-L132. ISSN 1745-3925.

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It has been established for decades that rotation curves deviate from the Newtonian gravity expectation given baryons alone below a characteristic acceleration scale g†∼10⁻⁸ cm s⁻²⁠, a scale promoted to a new fundamental constant in MOND. In recent years, theoretical and observational studies have shown that the star formation efficiency (SFE) of dense gas scales with surface density, SFE ∼ Σ/Σ_(crit) with Σ_(crit)∼⟨p˙/m∗⟩/(πG)∼1000 M_⊙ pc⁻² (where ⟨p˙/m∗⟩ is the momentum flux output by stellar feedback per unit stellar mass in a young stellar population). We argue that the SFE, more generally, should scale with the local gravitational acceleration, i.e. that SFE ∼g_(tot)/g_(crit) ≡ (GM_(tot)/R²)/⟨p˙/m∗⟩⁠, where M_(tot) is the total gravitating mass and g_(crit) = ⟨p˙/m∗⟩ = πGΣ_(crit) ≈ 10⁻⁸ cm s⁻² ≈ g†. Hence, the observed g† may correspond to the characteristic acceleration scale above which stellar feedback cannot prevent efficient star formation, and baryons will eventually come to dominate. We further show how this may give rise to the observed acceleration scaling g_(obs) ∼ (g_(baryon)g†)^(1/2) (where g_(baryon) is the acceleration due to baryons alone) and flat rotation curves. The derived characteristic acceleration g† can be expressed in terms of fundamental constants (gravitational constant, proton mass, and Thomson cross-section): g†∼0.1Gmp_/σ_T⁠.

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URLURL TypeDescription Paper
Grudić, Michael Y.0000-0002-1655-5604
Boylan-Kolchin, Michael0000-0002-9604-343X
Faucher-Giguère, Claude-André0000-0002-4900-6628
Hopkins, Philip F.0000-0003-3729-1684
Additional Information:© 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model ( Accepted 2020 April 17. Received 2020 April 10; in original form 2019 October 23. Published: 01 June 2020. We thank James Bullock, Manoj Kaplinghat, and Jonathan Stern for useful discussions, and the anonymous referees for various comments that improved and clarified this work. MYG was supported by the CIERA Postdoctoral Fellowship Program. MBK acknowledges support from NSF grants AST-1517226, AST-1910346, and CAREER award AST-1752913, NASA grant NNX17AG29G, and grants HST-AR-13888, HST-AR-13896, HST-AR-14282, HST-AR-14554, HST-AR-15006, HST-GO-12914, and HST-GO-14191 from the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS5-26555. CAFG was supported by NSF through grants AST-1517491, AST-1715216, and CAREER award AST-1652522, by NASA through grant 17-ATP17-0067, and by a Cottrell Scholar Award from the Research Corporation for Science Advancement. Support for PFH was provided by an Alfred P. Sloan Research Fellowship, NSF Collaborative Research Grant #1715847 and CAREER grant #1455342, and NASA grants NNX15AT06G, JPL 1589742, and 17-ATP17-0214.
Group:Astronomy Department, TAPIR
Funding AgencyGrant Number
Northwestern UniversityUNSPECIFIED
Cottrell Scholar of Research CorporationUNSPECIFIED
Alfred P. Sloan FoundationUNSPECIFIED
Subject Keywords:galaxies: evolution – galaxies: formation – cosmology: dark matter
Issue or Number:1
Record Number:CaltechAUTHORS:20200310-140049842
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Official Citation:Michael Y Grudić, Michael Boylan-Kolchin, Claude-André Faucher-Giguère, Philip F Hopkins, The universal acceleration scale from stellar feedback, Monthly Notices of the Royal Astronomical Society: Letters, Volume 496, Issue 1, July 2020, Pages L127–L132,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:101829
Deposited By: Tony Diaz
Deposited On:10 Mar 2020 21:26
Last Modified:08 Sep 2020 19:29

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