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Dwarf Galaxies in CDM, WDM, and SIDM: Disentangling Baryons and Dark Matter Physics

Fitts, Alex and Boylan-Kolchin, Michael and Bozek, Brandon and Bullock, James S. and Graus, Andrew and Robles, Victor and Hopkins, Philip F. and El-Badry, Kareem and Garrison-Kimmel, Shea and Faucher-Giguère, Claude-André and Wetzel, Andrew and Kereš, Dušan (2019) Dwarf Galaxies in CDM, WDM, and SIDM: Disentangling Baryons and Dark Matter Physics. Monthly Notices of the Royal Astronomical Society, 490 (1). pp. 962-977. ISSN 0035-8711.

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We present a suite of FIRE-2 cosmological zoom-in simulations of isolated field dwarf galaxies, all with masses of M_(halo) ≈ 10¹⁰M⊙ at z = 0, across a range of dark matter models. For the first time, we compare how both self-interacting dark matter (SIDM) and/or warm dark matter (WDM) models affect the assembly histories as well as the central density structure in fully hydrodynamical simulations of dwarfs. Dwarfs with smaller stellar half-mass radii (r_(1/2) < 500 pc) have lower σ⋆/V_(max) ratios, reinforcing the idea that smaller dwarfs may reside in haloes that are more massive than is naively expected. The majority of dwarfs simulated with self-interactions actually experience contraction of their inner density profiles with the addition of baryons relative to the cores produced in dark-matter-only runs, though the simulated dwarfs are always less centrally dense than in ΛCDM. The V_(1/2)–r_(1/2) relation across all simulations is generally consistent with observations of Local Field dwarfs, though compact objects such as Tucana provide a unique challenge. Overall, the inclusion of baryons substantially reduces any distinct signatures of dark matter physics in the observable properties of dwarf galaxies. Spatially resolved rotation curves in the central regions (<400 pc) of small dwarfs could provide a way to distinguish between CDM, WDM, and SIDM, however: at the masses probed in this simulation suite, cored density profiles in dwarfs with small r_(1/2) values can only originate from dark matter self-interactions.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Fitts, Alex0000-0002-8928-6011
Boylan-Kolchin, Michael0000-0002-9604-343X
Bullock, James S.0000-0003-4298-5082
Robles, Victor0000-0002-9497-9963
Hopkins, Philip F.0000-0003-3729-1684
El-Badry, Kareem0000-0002-6871-1752
Garrison-Kimmel, Shea0000-0002-4655-8128
Faucher-Giguère, Claude-André0000-0002-4900-6628
Wetzel, Andrew0000-0003-0603-8942
Kereš, Dušan0000-0002-1666-7067
Additional Information:© 2019 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 2019 September 12. Received 2019 September 12; in original form 2018 November 1. Published: 19 September 2019. AF thanks Bonnie and Emily Collins for the valuable discussions, and Alexander Knebe and Oliver Hahn for making AHF and MUSIC, respectively, publicly available. MBK and AF acknowledge support from the National Science Foundation (grant AST-1517226). MBK was also partially supported by NSFs CAREER grant AST-1752913 and NASA through grant NNX17AG29G and HST grants AR-12836, AR-13888, AR-13896, AR-14282, AR-14554, GO-12914, and GO-14191 awarded by the Space Telescope Science Institute (STScI), which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under NASA contract NAS5-26555. JSB was supported by NSF AST-1518291, HST-AR-14282, and HST-AR-13888. Support for PFH was provided by an Alfred P. Sloan Research Fellowship, NASA ATP Grant NNX14AH35G, and NSF Collaborative Research Grant #1411920 and CAREER grant #1455342. CAFG was supported by NSF through grants AST-1517491, AST-1715216, and CAREER award AST-1652522, by NASA through grants NNX15AB22G and 17-ATP17-0067, and by a Cottrell Scholar Award from the Research Corporation for Science Advancement. DK was supported by NSF grant AST-1715101 and the Cottrell Scholar Award from the Research Corporation for Science Advancement. AW was supported by NASA through ATP grant 80NSSC18K1097 and grants HST-GO-14734 and HST-AR-15057 from STScI. This work used computational resources of the University of Texas at Austin and the Texas Advanced Computing Center (TACC;, the NASA Advanced Supercomputing (NAS) Division and the NASA Center for Climate Simulation (NCCS) through allocations SMD-15-5902, SMD-15-5904, SMD-16-7043, and SMD-16-6991, and the Extreme Science and Engineering Discovery Environment (XSEDE, via allocations TG-AST110035, TG-AST130039, and TG-AST140080), which is supported by National Science Foundation grant number OCI-1053575.
Group:TAPIR, Astronomy Department
Funding AgencyGrant Number
Alfred P. Sloan FoundationUNSPECIFIED
Cottrell Scholar of Research CorporationUNSPECIFIED
Subject Keywords:galaxies: dwarf – galaxies: evolution – galaxies: formation – galaxies: star formation – galaxies: structure – dark matter
Issue or Number:1
Record Number:CaltechAUTHORS:20190206-105636977
Persistent URL:
Official Citation:Alex Fitts, Michael Boylan-Kolchin, Brandon Bozek, James S Bullock, Andrew Graus, Victor Robles, Philip F Hopkins, Kareem El-Badry, Shea Garrison-Kimmel, Claude-André Faucher-Giguère, Andrew Wetzel, Dušan Kereš, Dwarf galaxies in CDM, WDM, and SIDM: disentangling baryons and dark matter physics, Monthly Notices of the Royal Astronomical Society, Volume 490, Issue 1, November 2019, Pages 962–977,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:92729
Deposited By: George Porter
Deposited On:07 Feb 2019 16:00
Last Modified:09 Mar 2020 13:19

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