FIRE-2 simulations: physics versus numerics in galaxy formation. Issue 1 (28th June 2018)

• Record Type: Journal Article
• Authors: Hopkins, Philip F; Wetzel, Andrew; Kereš, Dušan; Faucher-Giguère, Claude-André; Quataert, Eliot; Boylan-Kolchin, Michael; Murray, Norman; Hayward, Christopher C; Garrison-Kimmel, Shea; Hummels, Cameron; Feldmann, Robert; Torrey, Paul; Ma, Xiangcheng; Anglés-Alcázar, Daniel; Su, Kung-Yi; Orr, Matthew; Schmitz, Denise; Escala, Ivanna; Sanderson, Robyn; Grudić, Michael Y; Hafen, Zachary; Kim, Ji-Hoon; Fitts, Alex; Bullock, James S; Wheeler, Coral; Chan, T K; Elbert, Oliver D; Narayanan, Desika
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 480:Issue 1(2018)
• Page Start: 800
• Page End: 863
• Publication Date: 2018-06-28
• Subjects: methods: numerical -- stars: formation -- galaxies: active -- galaxies: evolution -- galaxies: formation -- cosmology: theory; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/sty1690
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: The Feedback In Realistic Environments (FIRE) project explores feedback in cosmological galaxy formation simulations. Previous FIRE simulations used an identical source code ('FIRE-1') for consistency. Motivated by the development of more accurate numerics – including hydrodynamic solvers, gravitational softening, and supernova coupling algorithms – and exploration of new physics (e.g. magnetic fields), we introduce 'FIRE-2', an updated numerical implementation of FIRE physics for the gizmo code. We run a suite of simulations and compare against FIRE-1: overall, FIRE-2 improvements do not qualitatively change galaxy-scale properties. We pursue an extensive study of numerics versus physics. Details of the star formation algorithm, cooling physics, and chemistry have weak effects provided that we include metal-line cooling and star formation occurs at higher-than-mean densities. We present new resolution criteria for high-resolution galaxy simulations. Most galaxy-scale properties are robust to numerics we test, provided: (1) Toomre masses are resolved; (2) feedback coupling ensures conservation, and (3) individual supernovae are time-resolved. Stellar masses and profiles are most robust to resolution, followed by metal abundances and morphologies, followed by properties of winds and circum-galactic media. Central (∼kpc) mass concentrations in massive (> L * ) galaxies are sensitive to numerics (via trapping/recycling of winds in hot haloes). Multiple feedback mechanisms play key roles: supernovae regulate stellar masses/winds; stellar mass-loss fuels late star formation; radiative feedback suppresses accretion on to dwarfs and instantaneous star formation in discs. We provide all initial conditions and numerical algorithms used.