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Realistic HI scale heights of Milky Way-mass galaxies in the FIREbox cosmological volume

Gensior, Jindra and Feldmann, Robert and Mayer, Lucio and Wetzel, Andrew and Hopkins, Philip F. and Faucher-Giguère, Claude-André (2022) Realistic HI scale heights of Milky Way-mass galaxies in the FIREbox cosmological volume. . (Unpublished)

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Accurately reproducing the thin cold gas discs observed in nearby spiral galaxies has been a long standing issue in cosmological simulations. Here, we present measurements of the radially resolved HI scale height in 22 non-interacting Milky Way-mass galaxies from the FIREbox cosmological volume. We measure the HI scale heights using five different approaches commonly used in the literature: fitting the vertical volume density distribution with a Gaussian, the distance between maximum and half-maximum of the vertical volume density distribution, a semi-empirical description using the velocity dispersion and the galactic gravitational potential, the analytic assumption of hydrostatic equilibrium, and the distance from the midplane which encloses ≳60 per cent of the HI mass. We find median HI scale heights, measured using the vertical volume distribution, that range from ~100 pc in the galactic centres to ~800 pc in the outskirts and are in excellent agreement with recent observational results. We speculate that the presence of a realistic multiphase interstellar medium, including cold gas, and realistic stellar feedback are the drivers behind the realistic HI scale heights.

Item Type:Report or Paper (Discussion Paper)
Related URLs:
URLURL TypeDescription Paper
Gensior, Jindra0000-0001-6119-9883
Feldmann, Robert0000-0002-1109-1919
Wetzel, Andrew0000-0003-0603-8942
Hopkins, Philip F.0000-0003-3729-1684
Faucher-Giguère, Claude-André0000-0002-4900-6628
Additional Information:JG, RF and LM gratefully acknowledge financial support from the Swiss National Science Foundation (grant no CRSII5_193826). RF acknowledges financial support from the Swiss National Science Foundation (grant no PP00P2_194814 and 200021_188552). AW received support from: NSF via CAREER award AST-2045928 and grant AST-2107772; NASA ATP grant 80NSSC20K0513; HST grants AR-15809, GO-15902, GO-16273 from STScI. CAFG was supported by NSF through grants AST-1715216, AST-2108230, and CAREER award AST-1652522; by NASA through grants 17-ATP17-0067 and 21-ATP21-0036; by STScI through grants HST-AR-16124.001-A and HST-GO-16730.016-A; by CXO through grant TM2-23005X; and by the Research Corporation for Science Advancement through a Cottrell Scholar Award. We acknowledge PRACE for awarding us access to MareNostrum at the Barcelona Supercomputing Center (BSC), Spain. This work was supported in part by a grant from the Swiss National Supercomputing Centre (CSCS) under project IDs s697 and s698. We acknowledge access to Piz Daint at the Swiss National Supercomputing Centre, Switzerland under the University of Zurich’s share with the project ID uzh18. This work made use of infrastructure services provided by S3IT (, the Service and Support for Science IT team at the University of Zurich. DATA AVAILABILITY. The data underlying this article will be shared on reasonable request to the corresponding author.
Group:Astronomy Department, TAPIR
Funding AgencyGrant Number
Swiss National Science Foundation (SNSF)CRSII5_193826
Swiss National Science Foundation (SNSF)PP00P2_194814
Swiss National Science Foundation (SNSF)200021_188552
Cottrell Scholar of Research CorporationUNSPECIFIED
Swiss National Supercomputing Centre (CSCS)s697
Swiss National Supercomputing Centre (CSCS)s698
Swiss National Supercomputing Centre (CSCS)uzh18
University of ZurichUNSPECIFIED
Subject Keywords:galaxies: ISM – galaxies: spiral – galaxies: structure – ISM: structure – ISM: kinematics and dynamics
Record Number:CaltechAUTHORS:20220816-222008305
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:116331
Deposited By: George Porter
Deposited On:18 Aug 2022 22:29
Last Modified:18 Aug 2022 22:29

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