Cluster turbulence

Authors: Michael L Norman Greg L Bryan

Publish Date: 1999

Volume: , Issue: , Pages: 106-115

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Abstract

We report on results of recent high resolution hydrodynamic simulations of the formation and evolution of Xray clusters of galaxies carried out within a cosmological framework We employ the highly accurate piecewise parabolic method PPM on fixed and adaptive meshes which allow us to resolve the flow field in the intracluster gas The excellent shock capturing and low numerical viscosity of PPM represent a substantial advance over previous studies using SPH We find that in flat hierarchical cosmological models the ICM is in a turbulent state long after turbulence generated by the last major merger should have decayed away Turbulent velocities are found to vary slowly with cluster radius being ∼ 25 of σ vir in the core increasing to ∼ 60 at the virial radius We argue that more frequent minor mergers maintain the high level of turbulence found in the core where dynamical times are short Turbulent pressure support is thus significant throughout the cluster and results in a somewhat cooler cluster T/T vir ∼ 8 for its mass Some implications of cluster turbulence are discussed

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