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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