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arXiv · 1702.06148

FIRE-2 Simulations: Physics versus Numerics in Galaxy Formation

Philip F Hopkins·Andrew Wetzel·Dusan Keres·Claude-Andre Faucher-Giguere·Eliot Quataert·Michael Boylan-Kolchin·Norman Murray·Christopher C. Hayward·Shea Garrison-Kimmel·Cameron Hummels·Robert Feldmann·Paul Torrey·Xiangcheng Ma·Daniel Angles-Alcazar·Kung-Yi Su·Matthew Orr·Denise Schmitz·Ivanna Escala·Robyn Sanderson·Michael Y. Grudic·Zachary Hafen·Ji-Hoon Kim·Alex Fitts·James S. Bullock·Coral Wheeler·T. K. Chan·Oliver D. Elbert·Desika Narananan
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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 (CGM). Central (~kpc) mass concentrations in massive (L*) galaxies are sensitive to numerics (via trapping/recycling of winds in hot halos). Multiple feedback mechanisms play key roles: supernovae regulate stellar masses/winds; stellar mass-loss fuels late star formation; radiative feedback suppresses accretion onto dwarfs and instantaneous star formation in disks. We provide all initial conditions and numerical algorithms used.

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Philip F Hopkins, Andrew Wetzel, Dusan Keres, Claude-Andre Faucher-Giguere, Eliot Quataert, Michael Boylan-Kolchin, Norman Murray, Christopher C. Hayward, Shea Garrison-Kimmel, Cameron Hummels, Robert Feldmann, Paul Torrey, Xiangcheng Ma, Daniel Angles-Alcazar, Kung-Yi Su, Matthew Orr, Denise Schmitz, Ivanna Escala, Robyn Sanderson, Michael Y. Grudic, Zachary Hafen, Ji-Hoon Kim, Alex Fitts, James S. Bullock, Coral Wheeler, T. K. Chan, Oliver D. Elbert, Desika Narananan. 2017-02-20. FIRE-2 Simulations: Physics versus Numerics in Galaxy Formation. https://doi.org/10.1093/mnras%2Fsty1690

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