nIFTy Galaxy Cluster simulations IV: Quantifying the Influence of Baryons on Halo Properties

TL;DR

This study compares the effects of baryonic physics on galaxy cluster properties across different simulation codes, revealing consistent global measures but significant variations in detailed profiles, especially with complex baryonic physics.

Contribution

It provides a comprehensive comparison of baryonic physics impact on galaxy cluster simulations across multiple advanced codes, highlighting the diversity in cluster core properties.

Findings

Good consistency in global properties within R200 across codes.

Large differences in profiles within R2500, especially in full physics runs.

Diversity in cluster core profiles linked to simulation methods and baryonic physics.

Abstract

Building on the initial results of the nIFTy simulated galaxy cluster comparison, we compare and contrast the impact of baryonic physics with a single massive galaxy cluster, run with 11 state-of-the-art codes, spanning adaptive mesh, moving mesh, classic and modern SPH approaches. For each code represented we have a dark matter only (DM) and non-radiative (NR) version of the cluster, as well as a full physics (FP) version for a subset of the codes. We compare both radial mass and kinematic profiles, as well as global measures of the cluster (e.g. concentration, spin, shape), in the NR and FP runs with that in the DM runs. Our analysis reveals good consistency (<= 20%) between global properties of the cluster predicted by different codes when integrated quantities are measured within the virial radius R200. However, we see larger differences for quantities within R2500, especially in the FP runs. The radial profiles reveal a diversity, especially in the cluster centre, between the NR runs, which can be understood straightforwardly from the division of codes into classic SPH and non-classic SPH (including the modern SPH, adaptive and moving mesh codes); and between the FP runs, which can also be understood broadly from the division of codes into those that include AGN feedback and those that do not. The variation with respect to the median is much larger in the FP runs with different baryonic physics prescriptions than in the NR runs with different hydrodynamics solvers.