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Virialization of the Inner CGM in the FIRE Simulations and Implications for Galaxy Disks, Star Formation, and Feedback

Stern, Jonathan and Faucher-Giguère, Claude-André and Fielding, Drummond and Quataert, Eliot and Hafen, Zachary H. and Gurvich, Alexander B. and Ma, Xiangcheng and Byrne, Lindsey and El-Badry, Kareem and Anglés-Alcázar, Daniel and Chan, T. K. and Feldmann, Robert and Kereš, Dušan and Wetzel, Andrew and Murray, Norman and Hopkins, Philip F. (2021) Virialization of the Inner CGM in the FIRE Simulations and Implications for Galaxy Disks, Star Formation, and Feedback. Astrophysical Journal, 911 (2). Art. No. 88. ISSN 0004-637X. doi:10.3847/1538-4357/abd776.

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We use the FIRE-2 cosmological simulations to study the formation of a quasi-static, virial-temperature gas phase in the circumgalactic medium (CGM) at redshifts 0 < z < 5 and how the formation of this virialized phase affects the evolution of galactic disks. We demonstrate that when the halo mass crosses ~10¹² M_⊙, the cooling time of shocked gas in the inner CGM (~0.1R_(vir), where R_(vir) is the virial radius) exceeds the local free-fall time. The inner CGM then experiences a transition from on average subvirial temperatures (T « T_(vir)), large pressure fluctuations, and supersonic inflow/outflow velocities to virial temperatures (T ~ T_(vir)), uniform pressures, and subsonic velocities. This transition occurs when the outer CGM (~0.5R_(vir)) is already subsonic and has a temperature ~T_(vir), indicating that the longer cooling times at large radii allow the outer CGM to virialize at lower halo masses than the inner CGM. This outside-in CGM virialization scenario is in contrast with inside-out scenarios commonly envisioned based on more idealized simulations. We demonstrate that inner CGM virialization coincides with abrupt changes in the central galaxy and its stellar feedback: the galaxy settles into a stable rotating disk, star formation transitions from "bursty" to "steady," and stellar-driven galaxy-scale outflows are suppressed. Our results thus suggest that CGM virialization is initially associated with the formation of rotation-dominated thin galactic disks, rather than with the quenching of star formation as often assumed.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Stern, Jonathan0000-0002-7541-9565
Faucher-Giguère, Claude-André0000-0002-4900-6628
Fielding, Drummond0000-0003-3806-8548
Quataert, Eliot0000-0001-9185-5044
Hafen, Zachary H.0000-0001-7326-1736
Gurvich, Alexander B.0000-0002-6145-3674
Ma, Xiangcheng0000-0001-8091-2349
Byrne, Lindsey0000-0002-8408-1834
El-Badry, Kareem0000-0002-6871-1752
Anglés-Alcázar, Daniel0000-0001-5769-4945
Chan, T. K.0000-0003-2544-054X
Feldmann, Robert0000-0002-1109-1919
Kereš, Dušan0000-0002-1666-7067
Wetzel, Andrew0000-0003-0603-8942
Murray, Norman0000-0002-8659-3729
Hopkins, Philip F.0000-0003-3729-1684
Alternate Title:Virialization of the inner CGM in the FIRE simulations and implications for galaxy discs, star formation and feedback
Additional Information:© 2021. The American Astronomical Society. Received 2020 August 30; revised 2020 December 24; accepted 2020 December 28; published 2021 April 19. We thank Andrey Kravtsov and Clarke Esmerian for useful discussions and the anonymous referee for a highly insightful and thorough report. J.S. is supported by the CIERA Postdoctoral Fellowship Program. C.-A.F.-G. was supported by NSF through grants AST-1517491, AST-1715216, and CAREER award AST-1652522; by NASA through grant 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 and a Scialog Award from the Research Corporation for Science Advancement. D.F. is supported by the Flatiron Institute, which is supported by the Simons Foundation. E.Q. was supported in part by a Simons Investigator Award from the Simons Foundation and by NSF grant AST-1715070. A.G. was supported by the National Science Foundation and as a Blue Waters graduate fellow. T.K.C. is supported by Science and Technology Facilities Council astronomy consolidated grant ST/T000244/1. R.F. acknowledges financial support from the Swiss National Science Foundation (grant No. 157591). D.K. was supported by NSF grant AST-1715101 and the Cottrell Scholar Award from the Research Corporation for Science Advancement. A.W. received support from NASA through ATP grant 80NSSC18K1097 and HST grants GO-14734, AR-15057, AR-15809, and GO-15902 from STScI; the Heising-Simons Foundation; and a Hellman Fellowship. Some of the simulations were run using XSEDE (TG-AST160048), supported by NSF grant ACI-1053575, and Northwestern University's computer cluster "Quest."
Group:TAPIR, Astronomy Department
Funding AgencyGrant Number
Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA)UNSPECIFIED
Cottrell Scholar of Research CorporationUNSPECIFIED
Flatiron InstituteUNSPECIFIED
Simons FoundationUNSPECIFIED
National Center for Supercomputing Applications (NCSA)UNSPECIFIED
Science and Technology Facilities Council (STFC)ST/T000244/1
Swiss National Science Foundation157591
Heising-Simons FoundationUNSPECIFIED
Hellman FellowshipUNSPECIFIED
Subject Keywords:Galaxies
Issue or Number:2
Classification Code:Unified Astronomy Thesaurus concepts: Galaxies (573)
Record Number:CaltechAUTHORS:20210423-164858810
Persistent URL:
Official Citation:Jonathan Stern et al 2021 ApJ 911 88
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:108836
Deposited By: George Porter
Deposited On:27 Apr 2021 15:20
Last Modified:05 Jan 2023 23:04

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