@article{134c7d69afc641e6be35b468da3e079c,
title = "EDGE: The mass-metallicity relation as a critical test of galaxy formation physics",
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 (∼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.",
keywords = "Galaxies: dwarf, Galaxies: evolution, Galaxies: formation, Galaxies: kinematics and dynamics, Local Group, Methods: numerical",
author = "Oscar Agertz and Andrew Pontzen and Read, {Justin I.} and Rey, {Martin P.} and Matthew Orkney and Joakim Rosdahl and Romain Teyssier and Robbert verbeke and Michael Kretschmer and Sarah Nickerson",
note = "Funding Information: This work was partially enabled by support from the UCL Cosmoparticle Initiative. This work was performed in part using the DiRAC Data Intensive service at Leicester, operated by the University of Leicester IT Services, which forms part of the Science and Technology Facilities Council (STFC) DiRAC HPC Facility (www.dirac.ac.uk). The equipment was funded by BEIS capital funding via STFC capital grants ST/K000373/1 and ST/R002363/1 and STFC DiRAC Operations grant ST/R001014/1. DiRAC is part of the National e-Infrastructure. This work also used the COSMA Data Centric system at Durham University, operated by the Institute for Computational Cosmology on behalf of the STFC DiRAC HPC Facility (www.dirac.ac.uk). This equipment was funded by a BIS National E-infrastructure capital grant ST/K00042X/1, DiRAC Operations grant ST/K003267/1 and Durham University. DiRAC is part of the National E-Infrastructure. This work was also supported by a grant from the Swiss National Supercomputing Centre (CSCS) under project ID s890. Finally, a large number of simulations for this work were performed on computational resources at LUNARC, the center for scientific and technical computing at Lund University, thanks to financial support from the Royal Physiographic Society of Lund. Funding Information: OA acknowledges support from the Swedish Research Council (grant 2014-5791) and the Knut and Alice Wallenberg Foundation. AP is supported by the Royal Society. MR acknowledges support from the Perren Fund and the IMPACT fund. JR acknowledges support from the ORAGE project from the Agence Nationale de la Recherche under grant ANR-14-CE33-0016-03. Funding Information: The authors thank the referee Chia-Yu Hu for his constructive comments that improved the quality of the paper. We thank Coral Wheeler, Joshua Simon, Andrew Wetzel, Andrea Macci?, Yvez Revaz, and Alyson Brooks for helpful comments. OA acknowledges support from the Swedish Research Council (grant 2014-5791) and the Knut and Alice Wallenberg Foundation. AP is supported by the Royal Society. MR acknowledges support from the Perren Fund and the IMPACT fund. JR acknowledges support from the ORAGE project from the Agence Nationale de la Recherche under grant ANR-14-CE33-0016-03. This work was partially enabled by support from the UCL Cosmoparticle Initiative. This work was performed in part using the DiRAC Data Intensive service at Leicester, operated by the University of Leicester IT Services, which forms part of the Science and Technology Facilities Council (STFC) DiRAC HPC Facility (www.dirac.ac.uk). The equipment was funded by BEIS capital funding via STFC capital grants ST/K000373/1 and ST/R002363/1 and STFC DiRAC Operations grant ST/R001014/1. DiRAC is part of the National e-Infrastructure. This work also used the COSMA Data Centric system at Durham University, operated by the Institute for Computational Cosmology on behalf of the STFC DiRAC HPC Facility (www.dirac.ac.uk). This equipment was funded by a BIS National E-infrastructure capital grant ST/K00042X/1, DiRAC Operations grant ST/K003267/1 and Durham University. DiRAC is part of the National E-Infrastructure. This work was also supported by a grant from the Swiss National Supercomputing Centre (CSCS) under project ID s890. Finally, a large number of simulations for this work were performed on computational resources at LUNARC, the center for scientific and technical computing at Lund University, thanks to financial support from the Royal Physiographic Society of Lund. Publisher Copyright: {\textcopyright} 2019 The Author(s).",
year = "2020",
month = jan,
day = "1",
doi = "10.1093/mnras/stz3053",
language = "English (US)",
volume = "491",
pages = "1656--1672",
journal = "Monthly Notices of the Royal Astronomical Society",
issn = "0035-8711",
publisher = "Oxford University Press",
number = "2",
}