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

By S. Garrison-Kimmel, P. Hopkins, Andrew Wetzel, James S. Bullock, M. Boylan-Kolchin, D. Keres̆, C. Faucher-Giguére, K. El-Badry, A. Lamberts, E. Quataert and 1 more. Monthly notices of the Royal Astronomical Society, 2018

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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 Milky Way (MW)-like volumes (10 host systems in total with a baryonic particle mass ${\simeq } 3500\!-\!7000\,{\rm M}_\odot$). 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 of MW satellite dwarfs for $M_\ast \ge 10^{5.5}\,{\rm M}_\odot$ and predict the existence of ∼3 unidentified galaxies with $M_\ast \sim 10^5\,{\rm M}_\odot$ 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-of-yet unseen galaxies at distances $0.3\!-\!1\, \mathrm{Mpc}$ from both hosts, with $M_\ast \simeq 10^{5-6}\,{\rm M}_\odot$ (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 $r\lt 1\,$ 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.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/9caba668903808c7258ba99021688c722c34f256

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Citations in the corpus

Milky Way Satellite Census. II. Galaxy–Halo Connection Constraints Including the Impact of the Large Magellanic Cloud (2019, background): “Our results are largely consistent with the luminosity function of bright MW satellites in hydrodynamic simulations of the Local Group using the Feedback In Realistic Environments (FIRE) feedback prescription, down to the FIRE resolution limit of ∼ −6 mag (Garrison-Kimmel et al. 2019).”
Milky Way Satellite Census. I. The Observational Selection Function for Milky Way Satellites in DES Y3 and Pan-STARRS DR1 (2019, methodology): “…simulations that self-consistently model galaxy formation in a cosmological context produce luminosity functions and radial distributions of satellites that are broadly consistent with observations of the Milky Way system (e.g., Wetzel et al. 2016; Garrison-Kimmel et al. 2019; Samuel et al. 2020).”