Turbulent Velocity Fields in SPH--simulated Galaxy Clusters

TL;DR

This study investigates turbulent velocity fields in galaxy clusters using SPH simulations with a novel viscosity scheme, revealing that turbulence energy scales with cluster thermal energy and aligns with semi-analytical models.

Contribution

Introduces a new numerical scheme for SPH simulations that better isolates turbulence, and analyzes the scaling laws of turbulent energy in galaxy clusters.

Findings

Turbulent energy scales approximately with thermal energy in clusters.

The new numerical scheme effectively distinguishes turbulent motions from bulk flows.

Results agree with semi-analytical calculations over a wide mass range.

Abstract

We present a study of the turbulent velocity fields in the Intra Cluster Medium of a sample of 21 galaxy clusters simulated by the SPH--code Gadget2, using a new numerical scheme where the artificial viscosity is suppressed outside shocks. The turbulent motions in the ICM of our simulated clusters are detected with a novel method devised to better disentangle laminar bulk motions from chaotic ones. We focus on the scaling law between the turbulent energy content of the gas particles and the total mass, and find that the energy in the form of turbulence scales approximatively with the thermal energy of clusters. We follow the evolution with time of the scaling laws and discuss the physical origin of the observed trends. The simulated data are in agreement with independent semi--analytical calculations, and the combination between the two methods allows to constrain the scaling law over more than two decades in cluster mass.