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. 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.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- October 2018
- DOI:
- 10.1093/mnras/sty1690
- arXiv:
- arXiv:1702.06148
- Bibcode:
- 2018MNRAS.480..800H
- Keywords:
-
- methods: numerical;
- stars: formation;
- galaxies: active;
- galaxies: evolution;
- galaxies: formation;
- cosmology: theory;
- Astrophysics - Astrophysics of Galaxies;
- Astrophysics - Cosmology and Nongalactic Astrophysics;
- Astrophysics - Instrumentation and Methods for Astrophysics
- E-Print:
- 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