The Santa Barbara Cluster Comparison Project: A Comparison of Cosmological Hydrodynamics Solutions

Abstract

We have simulated the formation of an X-ray cluster in a cold dark matter universe using 12 different codes. The codes span the range of numerical techniques and implementations currently in use, including SPH and grid methods with fixed, deformable or multilevel meshes. The goal of this comparison is to assess the reliability of cosmological gas dynamical simulations of clusters in the simplest astrophysically relevant case, that in which the gas is assumed to be non-radiative. We compare images of the cluster at different epochs, global properties such as mass, temperature and X-ray luminosity, and radial profiles of various dynamical and thermodynamical quantities. On the whole, the agreement among the various simulations is gratifying although a number of discrepancies exist. Agreement is best for properties of the dark matter and worst for the total X-ray luminosity. Even in this case, simulations that adequately resolve the core radius of the gas distribution predict total X-ray luminosities that agree to within a factor of two. Other quantities are reproduced to much higher accuracy. For example, the temperature and gas mass fraction within the virial radius agree to about 10%, and the ratio of specific kinetic to thermal energies of the gas agree to about 5%. Various factors contribute to the spread in calculated cluster properties, including differences in the internal timing of the simulations. Based on the overall consistency of results, we discuss a number of general properties of the cluster we have modelled.

Searching for FUV line emission from 107 K gas in massive elliptical galaxies and galaxy clusters as a tracer of turbulent velocities

“…On large scales, this is predicted by numerical simulations (e.g. Norman & Bryan 1999, Frenk et al 1999 due to mergers and the accretion of satellites. In the centers of these systems, turbulence and bulk flows are also introduced by active galactic nucleus (AGN) feedback (Churazov et al 2001); other mechanisms such as cosmic ray-driven instabilities (Sharma et al 2009) and galactic stirring (Kim 2007;Ruszkowski & Oh 2010) may also be important in the intracluster medium.…”

GADGET: a code for collisionless and gasdynamical cosmological simulations

“…Among them are TREESPH (Hernquist & Katz 1989;Katz et al 1996), GRAPE-SPH (Steinmetz 1996), HYDRA (Couchman et al 1995;Pearce & Couchman 1997), and codes by Evrard (1988); Navarro & White (1993); Hultman & Källander (1997); Davé et al (1997); Carraro et al (1998). See Kang et al (1994) and Frenk et al (1999) for a comparison of many of these cosmological hydrodynamic codes.…”

Masclet: a new multidimensional AMR cosmological code

“…The best test we can think of for a cosmological code in a realistic setting is to compare with the results presented in Frenk et al (1999). In this reference, authors performed adiabatic simulations of a galaxy cluster with several codes.…”