The neutral hydrogen content of galaxies in cosmological hydrodynamic simulations

Romeel Davé, Neal Katz, Benjamin D. Oppenheimer, Juna A. Kollmeier, David H. Weinberg

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

We examine the global H I properties of galaxies in quarter billion particle cosmological simulations using GADGET-2, focusing on how galactic outflows impact H I content. We consider four outflow models, including a new one (ezw) motivated by recent interstellar medium simulations in which the wind speed and mass loading factor scale as expected for momentum-driven outflows for larger galaxies and energy-driven outflows for dwarfs (σ <75 km s-1). To obtain predicted H I masses, we employ a simple but effective local correction for particle self-shielding and an observationally constrained transition from neutral to molecular hydrogen. Our ezw simulation produces an H I mass function whose faint-end slope of -1.3 agrees well with observations from the Arecibo Fast Legacy ALFA survey; other models agree less well. Satellite galaxies have a bimodal distribution in H I fraction versus halo mass, with smaller satellites and/or those in larger haloes more often being H I deficient. At a given stellar mass, H I content correlates with the star formation rate and inversely correlates with metallicity, as expected if driven by stochasticity in the accretion rate. To higher redshifts, massive H I galaxies disappear and the mass function steepens. The global cosmic H I density conspires to remain fairly constant from z ˜ 5 → 0, but the relative contribution from smaller galaxies increases with redshift.
Original languageEnglish
Pages (from-to)2645-2663
JournalMonthly Notices of the Royal Astronomical Society
Volume434
Issue number3
DOIs
Publication statusPublished - 1 Aug 2013

Keywords / Materials (for Non-textual outputs)

  • ISM: atoms
  • galaxies: abundances
  • galaxies: evolution
  • galaxies: formation
  • galaxies: ISM

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