FIRE-2 Simulations: Physics versus Numerics in Galaxy Formation
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.
Cite
@article{arxiv.1702.06148,
title = {FIRE-2 Simulations: Physics versus Numerics in Galaxy Formation},
author = {Philip F Hopkins and Andrew Wetzel and Dusan Keres and Claude-Andre Faucher-Giguere and Eliot Quataert and Michael Boylan-Kolchin and Norman Murray and Christopher C. Hayward and Shea Garrison-Kimmel and Cameron Hummels and Robert Feldmann and Paul Torrey and Xiangcheng Ma and Daniel Angles-Alcazar and Kung-Yi Su and Matthew Orr and Denise Schmitz and Ivanna Escala and Robyn Sanderson and Michael Y. Grudic and Zachary Hafen and Ji-Hoon Kim and Alex Fitts and James S. Bullock and Coral Wheeler and T. K. Chan and Oliver D. Elbert and Desika Narananan},
journal= {arXiv preprint arXiv:1702.06148},
year = {2018}
}
Comments
64 pages, 40 figures. Simulation animations and visualizations available at http://www.tapir.caltech.edu/~phopkins/Site/animations and http://fire.northwestern.edu . Paper includes complete FIRE algorithms and public ICs (http://www.tapir.caltech.edu/~phopkins/publicICs). Updated to match published version