Turbulent velocity fields in smoothed particle hydrodymanics simulated galaxy clusters: Scaling laws for the turbulent energy

We present a study of the turbulent velocity fields in the intracluster medium (ICM) of a sample of 21 galaxy clusters simulated by the smoothed particle hydrodynamics 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 approximately 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 one to constrain the scaling law over more than two decades in cluster mass. © 2006 The Authors. Journal compilation © 2006 RAS.