The Local Group on FIRE: Dwarf galaxy populations across a suite of hydrodynamic simulations

Shea Garrison-Kimmel, Philip F. Hopkins, Andrew Wetzel, James S. Bullock, Michael Boylan-Kolchin, Dušan Kereš, Claude André Faucher-Giguère, Kareem El-Badry, Astrid Lamberts, Eliot Quataert, Robyn Sanderson

Research output: Contribution to journalArticlepeer-review

65 Scopus citations

Abstract

We present a new set of high-resolution hydrodynamic cosmological zoom-in simulations that apply the Feedback In Realistic Environments physics to both Local Group (LG)-like and isolated MilkyWay (MW)-like volumes (10 host systems in total with a baryonic particle mass ≃3500-7000M⊙).We study the stellar mass functions, circular velocity or mass profiles, and velocity dispersions of the dwarf galaxy populations. The simulations reproduce the stellar mass function and central densities ofMWsatellite dwarfs forM∗≥105.5M⊙ and predict the existence of ∼3 unidentified galaxies with M∗∼ 105M⊙ within 300 kpc of the MW. Overall, we find no evidence for the classical missing satellites or too-big-to-fail (TBTF) problems for satellite galaxies in our sample. Among the satellites, TBTF is resolved primarily by subhalo disruption and overall mass-loss; central density profiles of subhaloes are of secondary importance. For non-satellite galaxies, our LG-like simulations predict as many as ∼10 as-ofyet unseen galaxies at distances 0.3-1Mpc from both hosts, with M∗≃ 105-6M⊙ (in haloes with Vmax ∼ 20 km s-1), albeit with large halo-to-halo variance. None of our simulations produces a compact, baryon-dominated, high-density dwarf elliptical-type galaxy (with Vcirc ≳ 35 km s-1 at r < 1 kpc), of which six may appear in the LG (but none in the MW). It may therefore remain a challenge to reproduce the full diversity of the dwarf population, including both the highest and lowest density systems.

Original languageEnglish (US)
Pages (from-to)1380-1399
Number of pages20
JournalMonthly Notices of the Royal Astronomical Society
Volume487
Issue number1
DOIs
StatePublished - Jul 1 2019
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • Cosmology: Theory
  • Galaxies: Dwarf
  • Galaxies: Formation
  • Galaxies: Local Group

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