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The Origins of the Circumgalactic Medium in the FIRE Simulations

Hafen, Zachary and Faucher-Giguère, Claude-André and Anglés-Alcázar, Daniel and Stern, Jonathan and Kereš, Dušan and Hummels, Cameron and Esmerian, Clarke and Garrison-Kimmel, Shea and El-Badry, Kareem and Wetzel, Andrew and Chan, T. K. and Hopkins, Philip F. and Murray, Norman (2019) The Origins of the Circumgalactic Medium in the FIRE Simulations. Monthly Notices of the Royal Astronomical Society, 488 (1). pp. 1248-1272. ISSN 0035-8711.

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We use a particle tracking analysis to study the origins of the circumgalactic medium (CGM), separating it into (1) accretion from the intergalactic medium (IGM), (2) wind from the central galaxy, and (3) gas ejected from other galaxies. Our sample consists of 21 FIRE-2 simulations, spanning the halo mass range Mh ∼ 10^(10)–10^(12) M⊙, and we focus on z = 0.25 and z = 2. Owing to strong stellar feedback, only ∼L⋆ haloes retain a baryon mass ≳50 per cent of their cosmic budget. Metals are more efficiently retained by haloes, with a retention fraction ≳50 per cent⁠. Across all masses and redshifts analysed ≳60 per cent of the CGM mass originates as IGM accretion (some of which is associated with infalling haloes). Overall, the second most important contribution is wind from the central galaxy, though gas ejected or stripped from satellites can contribute a comparable mass in ∼L⋆ haloes. Gas can persist in the CGM for billions of years, resulting in well mixed-halo gas. Sightlines through the CGM are therefore likely to intersect gas of multiple origins. For low-redshift ∼L⋆ haloes, cool gas (T < 10^(4.7) K) is distributed on average preferentially along the galaxy plane, however with strong halo-to-halo variability. The metallicity of IGM accretion is systematically lower than the metallicity of winds (typically by ≳1 dex), although CGM and IGM metallicities depend significantly on the treatment of subgrid metal diffusion. Our results highlight the multiple physical mechanisms that contribute to the CGM and will inform observational efforts to develop a cohesive picture.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Hafen, Zachary0000-0001-7326-1736
Faucher-Giguère, Claude-André0000-0002-4900-6628
Anglés-Alcázar, Daniel0000-0001-5769-4945
Kereš, Dušan0000-0002-1666-7067
Hummels, Cameron0000-0002-3817-8133
Garrison-Kimmel, Shea0000-0002-4655-8128
El-Badry, Kareem0000-0002-6871-1752
Wetzel, Andrew0000-0003-0603-8942
Chan, T. K.0000-0003-2544-054X
Hopkins, Philip F.0000-0003-3729-1684
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 June 25. Received 2019 June 24; in original form 2018 November 28. Published: 28 June 2019. We thank Andrey Kravtsov, Thorsten Naab, Sarah Wellons, Hsiao-Wen Chen, Michele Fumagalli, John Stocke, Jason Tumlinson, Nicolas Lehner, and Rachel Somerville for useful discussions. We thank our referee, Dylan Nelson, for a comprehensive response that greatly improved the quality of this work. We thank Alex Gurvich for help integrating FIREFLY into our analysis. We thank Peter Behroozi for the making the UniverseMachine Early Data Release available (Behroozi et al. 2018). Zach Hafen was supported by the National Science Foundation under grant DGE-0948017. CAFG was supported by NSF through grants AST-1412836, AST-1517491, AST-1715216, and CAREER award AST-1652522, by NASA through grants NNX15AB22G and 17-ATP17-0067, by STScI through grants HST-GO-14681.011, HST-GO-14268.022-A, and HST-AR-14293.001-A, and by a Cottrell Scholar Award from the Research Corporation for Science Advancement. DAA acknowledges support by a Flatiron Fellowship. The Flatiron Institute is supported by the Simons Foundation. JS is supported as a CIERA Fellow by the CIERA Postdoctoral Fellowship Program (Center for Interdisciplinary Exploration and Research in Astrophysics, Northwestern University). DK and TKC were supported by NSF grant AST-1715101 and by a Cottrell Scholar Award from the Research Corporation for Science Advancement. Support for CBH was provided by NASA through Hubble Space Telescope (HST) theory grants HST-AR-13917 with additional funding from the NSF Astronomy and Astrophysics Postdoctoral Fellowship program. CE acknowledges support from NSF grant AST-1714658. Support for SGK and 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, 17-ATP17-0214. KE was supported by an National Science Foundation Graduate Research Fellowship. AW was supported by NASA through ATP grant 80NSSC18K1097, and grants HST-GO-14734 and HST-AR-15057 from STScI. NM acknowledges the support of the Natural Sciences and Engineering Research Council of Canada (NSERC). This research was undertaken, in part, thanks to funding from the Canada Research Chairs program. Numerical calculations were run on the Quest computing cluster at Northwestern University, the Wheeler computing cluster at Caltech, XSEDE allocations TG-AST130039 and TG-AST120025; Blue Waters PRAC allocation NSF.1713353, and NASA HEC allocation SMD-16-7592.
Group:TAPIR, Astronomy Department
Funding AgencyGrant Number
NSF Graduate Research FellowshipDGE-0948017
Cottrell Scholar of Research CorporationUNSPECIFIED
Flatiron InstituteUNSPECIFIED
Simons FoundationUNSPECIFIED
Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA)UNSPECIFIED
NASA Hubble FellowshipHST-AR-13917
NSF Astronomy and Astrophysics FellowshipUNSPECIFIED
Alfred P. Sloan FoundationUNSPECIFIED
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
Canada Research Chairs ProgramUNSPECIFIED
Subject Keywords:galaxies: formation, galaxies: evolution, galaxies: haloes, intergalactic medium, cosmology: theory, galaxies: interactions
Issue or Number:1
Record Number:CaltechAUTHORS:20190206-105631812
Persistent URL:
Official Citation:Zachary Hafen, Claude-André Faucher-Giguère, Daniel Anglés-Alcázar, Jonathan Stern, Dušan Kereš, Cameron Hummels, Clarke Esmerian, Shea Garrison-Kimmel, Kareem El-Badry, Andrew Wetzel, T K Chan, Philip F Hopkins, Norman Murray, The origins of the circumgalactic medium in the FIRE simulations, Monthly Notices of the Royal Astronomical Society, Volume 488, Issue 1, September 2019, Pages 1248–1272,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:92728
Deposited By: George Porter
Deposited On:07 Feb 2019 16:04
Last Modified:09 Mar 2020 13:18

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