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EDGE : The mass-metallicity relation as a critical test of galaxy formation physics

Agertz, Oscar LU ; Pontzen, Andrew ; Read, Justin I. ; Rey, Martin P. LU ; Orkney, Matthew ; Rosdahl, Joakim ; Teyssier, Romain ; verbeke, Robbert ; Kretschmer, Michael and Nickerson, Sarah (2020) In Monthly Notices of the Royal Astronomical Society 491(2). p.1656-1672
Abstract

We introduce the 'Engineering Dwarfs at Galaxy Formation's Edge' (EDGE) project to study the cosmological formation and evolution of the smallest galaxies in the Universe. In this first paper, we explore the effects of resolution and sub-grid physics on a single low-mass halo (Mhalo = 109M⊙), simulated to redshift z = 0 at amass and spatial resolution of ∼ 20 M⊙ and ∼3 pc. We consider different star formation prescriptions, supernova feedback strengths, and on-the-fly radiative transfer (RT). We show that RT changes the mode of galactic self-regulation at this halo mass, suppressing star formation by causing the interstellar and circumgalactic gas to remain predominantly warm... (More)

We introduce the 'Engineering Dwarfs at Galaxy Formation's Edge' (EDGE) project to study the cosmological formation and evolution of the smallest galaxies in the Universe. In this first paper, we explore the effects of resolution and sub-grid physics on a single low-mass halo (Mhalo = 109M⊙), simulated to redshift z = 0 at amass and spatial resolution of ∼ 20 M⊙ and ∼3 pc. We consider different star formation prescriptions, supernova feedback strengths, and on-the-fly radiative transfer (RT). We show that RT changes the mode of galactic self-regulation at this halo mass, suppressing star formation by causing the interstellar and circumgalactic gas to remain predominantly warm (∼104K) even before cosmic reionization. By contrast, without RT, star formation regulation occurs only through starbursts and their associated vigorous galactic outflows. In spite of this difference, the entire simulation suite (with the exception of models without any feedback) matches observed dwarf galaxy sizes, velocity dispersions, V-band magnitudes, and dynamical mass-to-light-ratios. This is because such structural scaling relations are predominantly set by the host dark matter halo, with the remaining model-to-model variation being smaller than the observational scatter. We find that only the stellar mass-metallicity relation differentiates the galaxy formation models. Explosive feedback ejects more metals from the dwarf, leading to a lower metallicity at a fixed stellar mass. We conclude that the stellar mass-metallicity relation of the very smallest galaxies provides a unique constraint on galaxy formation physics.

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author
; ; ; ; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Galaxies: dwarf, Galaxies: evolution, Galaxies: formation, Galaxies: kinematics and dynamics, Local Group, Methods: numerical
in
Monthly Notices of the Royal Astronomical Society
volume
491
issue
2
pages
17 pages
publisher
Oxford University Press
external identifiers
  • scopus:85079451204
ISSN
0035-8711
DOI
10.1093/mnras/stz3053
language
English
LU publication?
yes
id
b57a5e02-8fb9-4672-bdda-86f41d1dbf5a
date added to LUP
2020-12-18 12:52:51
date last changed
2024-04-17 21:23:50
@article{b57a5e02-8fb9-4672-bdda-86f41d1dbf5a,
  abstract     = {{<p>We introduce the 'Engineering Dwarfs at Galaxy Formation's Edge' (EDGE) project to study the cosmological formation and evolution of the smallest galaxies in the Universe. In this first paper, we explore the effects of resolution and sub-grid physics on a single low-mass halo (M<sub>halo</sub> = 10<sup>9</sup>M<sub>⊙</sub>), simulated to redshift z = 0 at amass and spatial resolution of ∼ 20 M<sub>⊙</sub> and ∼3 pc. We consider different star formation prescriptions, supernova feedback strengths, and on-the-fly radiative transfer (RT). We show that RT changes the mode of galactic self-regulation at this halo mass, suppressing star formation by causing the interstellar and circumgalactic gas to remain predominantly warm (∼10<sup>4</sup>K) even before cosmic reionization. By contrast, without RT, star formation regulation occurs only through starbursts and their associated vigorous galactic outflows. In spite of this difference, the entire simulation suite (with the exception of models without any feedback) matches observed dwarf galaxy sizes, velocity dispersions, V-band magnitudes, and dynamical mass-to-light-ratios. This is because such structural scaling relations are predominantly set by the host dark matter halo, with the remaining model-to-model variation being smaller than the observational scatter. We find that only the stellar mass-metallicity relation differentiates the galaxy formation models. Explosive feedback ejects more metals from the dwarf, leading to a lower metallicity at a fixed stellar mass. We conclude that the stellar mass-metallicity relation of the very smallest galaxies provides a unique constraint on galaxy formation physics.</p>}},
  author       = {{Agertz, Oscar and Pontzen, Andrew and Read, Justin I. and Rey, Martin P. and Orkney, Matthew and Rosdahl, Joakim and Teyssier, Romain and verbeke, Robbert and Kretschmer, Michael and Nickerson, Sarah}},
  issn         = {{0035-8711}},
  keywords     = {{Galaxies: dwarf; Galaxies: evolution; Galaxies: formation; Galaxies: kinematics and dynamics; Local Group; Methods: numerical}},
  language     = {{eng}},
  number       = {{2}},
  pages        = {{1656--1672}},
  publisher    = {{Oxford University Press}},
  series       = {{Monthly Notices of the Royal Astronomical Society}},
  title        = {{EDGE : The mass-metallicity relation as a critical test of galaxy formation physics}},
  url          = {{http://dx.doi.org/10.1093/mnras/stz3053}},
  doi          = {{10.1093/mnras/stz3053}},
  volume       = {{491}},
  year         = {{2020}},
}