Dynamic Equilibrium Sets of the Atomic Content of Galaxies across Cosmic Time

Liang Wang, Danail Obreschkow, Claudia D.P. Lagos, Sarah M. Sweet, Deanne B. Fisher, Karl Glazebrook, Andrea Maccio, Aaron A. Dutton, Xi Kang

    Research output: Contribution to journalArticle

    Abstract

    We analyze 88 independent, high-resolution, cosmological zoomed-in simulations of disk galaxies in the NIHAO simulations suite to explore the connection between the atomic gas fraction and angular momentum (AM) of baryons throughout cosmic time. The study is motivated by the analytical model of Obreschkow et al., which predicts a relation between the atomic gas fraction f atm and the integrated atomic stability parameter q ≡ jσ/(GM), where M and j are the mass and specific AM of the galaxy (stars+cold gas) and σ is the velocity dispersion of the atomic gas. We show that the simulated galaxies follow this relation from their formation (z ≃ 4) to the present within ∼0.5 dex. To explain this behavior, we explore the evolution of the local Toomre stability and find that 90%-100% of the atomic gas in all simulated galaxies is stable at any time. In other words, throughout the entire epoch of peak star formation until today, the timescale for accretion is longer than the timescale to reach equilibrium, thus resulting in a quasi-static equilibrium of atomic gas at any time. Hence, the evolution of f atm depends on the complex hierarchical growth history primarily via the evolution of q. An exception is galaxies subject to strong environmental effects.

    Original languageEnglish (US)
    Article number93
    JournalAstrophysical Journal
    Volume868
    Issue number2
    DOIs
    StatePublished - Dec 1 2018

    Fingerprint

    monatomic gases
    galaxies
    gas
    angular momentum
    cold gas
    disk galaxies
    timescale
    star formation
    baryons
    environmental effect
    simulation
    time measurement
    histories
    momentum
    stars
    accretion
    high resolution
    history

    Keywords

    • galaxies: dwarf
    • galaxies: evolution
    • galaxies: formation
    • galaxies: spiral
    • methods: numerical

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Space and Planetary Science

    Cite this

    Wang, L., Obreschkow, D., Lagos, C. D. P., Sweet, S. M., Fisher, D. B., Glazebrook, K., ... Kang, X. (2018). Dynamic Equilibrium Sets of the Atomic Content of Galaxies across Cosmic Time. Astrophysical Journal, 868(2), [93]. https://doi.org/10.3847/1538-4357/aae8de

    Dynamic Equilibrium Sets of the Atomic Content of Galaxies across Cosmic Time. / Wang, Liang; Obreschkow, Danail; Lagos, Claudia D.P.; Sweet, Sarah M.; Fisher, Deanne B.; Glazebrook, Karl; Maccio, Andrea; Dutton, Aaron A.; Kang, Xi.

    In: Astrophysical Journal, Vol. 868, No. 2, 93, 01.12.2018.

    Research output: Contribution to journalArticle

    Wang, L, Obreschkow, D, Lagos, CDP, Sweet, SM, Fisher, DB, Glazebrook, K, Maccio, A, Dutton, AA & Kang, X 2018, 'Dynamic Equilibrium Sets of the Atomic Content of Galaxies across Cosmic Time', Astrophysical Journal, vol. 868, no. 2, 93. https://doi.org/10.3847/1538-4357/aae8de
    Wang L, Obreschkow D, Lagos CDP, Sweet SM, Fisher DB, Glazebrook K et al. Dynamic Equilibrium Sets of the Atomic Content of Galaxies across Cosmic Time. Astrophysical Journal. 2018 Dec 1;868(2). 93. https://doi.org/10.3847/1538-4357/aae8de
    Wang, Liang ; Obreschkow, Danail ; Lagos, Claudia D.P. ; Sweet, Sarah M. ; Fisher, Deanne B. ; Glazebrook, Karl ; Maccio, Andrea ; Dutton, Aaron A. ; Kang, Xi. / Dynamic Equilibrium Sets of the Atomic Content of Galaxies across Cosmic Time. In: Astrophysical Journal. 2018 ; Vol. 868, No. 2.
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