The robustness of cosmological hydrodynamic simulation predictions to changes in numerics and cooling physics

Shuiyao Huang, Neal Katz, Romeel Davé, Mark Fardal, Juna Kollmeier, Benjamin D. Oppenheimer, Molly S. Peeples, Shawn Roberts, David H. Weinberg, Philip F. Hopkins, Robert Thompson

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

We test and improve the numerical schemes in our smoothed particle hydrodynamics (SPH) code for cosmological simulations, including the pressure-entropy formulation (PESPH), a time-dependent artificial viscosity, a refined time-step criterion, and metal-line cooling that accounts for photoionization in the presence of a recently refined Haardt & Madau model of the ionizing background. The PESPH algorithm effectively removes the artificial surface tension present in the traditional SPH formulation, and in our test simulations, it produces better qualitative agreement with mesh-code results for Kelvin-Helmholtz instability and cold cloud disruption. Using a set of cosmological simulations, we examine many of the quantities we have studied in previous work. Results for galaxy stellar and HI mass functions, star formation histories, galaxy scaling relations, and statistics of the Lyα forest are robust to the changes in numerics and microphysics. As in our previous simulations, cold gas accretion dominates the growth of high-redshift galaxies and of low-mass galaxies at low redshift, and recycling of winds dominates the growth of massive galaxies at low redshift. However, the PESPH simulation removes spurious cold clumps seen in our earlier simulations, and the accretion rate of hot gas increases by up to an order of magnitude at some redshifts. The new numerical model also influences the distribution of metals among gas phases, leading to considerable differences in the statistics of some metal absorption lines, most notably NeVIII.

Original languageEnglish
Pages (from-to)2021-2046
Number of pages26
JournalMonthly Notices of the Royal Astronomical Society
Issue number2
Early online date12 Jan 2019
Publication statusPublished - 1 Apr 2019

Keywords / Materials (for Non-textual outputs)

  • Galaxies: evolution
  • Galaxies: general
  • Hydrodynamics
  • Methods: numerical


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