The AGORA High-Resolution Galaxy Simulations Comparison Project. II: Isolated Disk Test
Creators: name: Kim, Ji-hoon
name: Agertz, Oscar
name: Teyssier, Romain
name: Butler, Michael J.
name: Ceverino, Daniel
name: Choi, Jun-Hwan
name: Feldmann, Robert
name: Keller, Ben W.
name: Lupi, Alessandro
name: Quinn, Thomas
name: Revaz, Yves
name: Wallace, Spencer
name: Gnedin, Nickolay Y.
name: Leitner, Samuel N.
name: Shen, Sijing
name: Smith, Britton D.
name: Thompson, Robert
name: Turk, Matthew J.
name: Abel, Tom
name: Arraki, Kenza S.
name: Benincasa, Samantha M.
name: Chakrabarti, Sukanya
name: DeGraf, Colin
name: Dekel, Avishai
name: Goldbaum, Nathan J.
name: Hopkins, Philip F.
name: Hummels, Cameron B.
name: Klypin, Anatoly
name: Li, Hui
name: Madau, Piero
name: Mandelker, Nir
name: Mayer, Lucio
name: Nagamine, Kentaro
name: Nickerson, Sarah
name: O'Shea, Brian W.
name: Primack, Joel R.
name: Roca-Fàbrega, Santi
name: Semenov, Vadim
name: Shimizu, Ikkoh
name: Simpson, Christine M.
name: Todoroki, Keita
name: Wadsley, James W.
name: Wise, John H.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: Using an isolated Milky Way-mass galaxy simulation, we compare results from 9 state-of-the-art gravito-hydrodynamics codes widely used in the numerical community. We utilize the infrastructure we have built for the AGORA High-resolution Galaxy Simulations Comparison Project. This includes the common disk initial conditions, common physics models (e.g., radiative cooling and UV background by the standardized package Grackle) and common analysis toolkit yt, all of which are publicly available. Subgrid physics models such as Jeans pressure floor, star formation, supernova feedback energy, and metal production are carefully constrained across code platforms. With numerical accuracy that resolves the disk scale height, we find that the codes overall agree well with one another in many dimensions including: gas and stellar surface densities, rotation curves, velocity dispersions, density and temperature distribution functions, disk vertical heights, stellar clumps, star formation rates, and Kennicutt-Schmidt relations. Quantities such as velocity dispersions are very robust (agreement within a few tens of percent at all radii) while measures like newly-formed stellar clump mass functions show more significant variation (difference by up to a factor of ~3). Systematic differences exist, for example, between mesh-based and particle-based codes in the low density region, and between more diffusive and less diffusive schemes in the high density tail of the density distribution. Yet intrinsic code differences are generally small compared to the variations in numerical implementations of the common subgrid physics such as supernova feedback. Our experiment reassures that, if adequately designed in accordance with our proposed common parameters, results of a modern high-resolution galaxy formation simulation are more sensitive to input physics than to intrinsic differences in numerical schemes.
description: 28 pages, 35 figures, Accepted for publication in the Astrophysical Journal, Image resolution greatly reduced, High-resolution version of this article is available at http://www.jihoonkim.org/agora/AGORA_Paper4_draft.pdf, The first paper of the AGORA Initiative is at http://adsabs.harvard.edu/abs/2014ApJS..210...14K, More information on AGORA is at http://www.AGORAsimulations.org/