Nonthermal support for the outer intracluster medium

Cavaliere, A.; Lapi, A.; Fusco-Femiano, R.

doi:10.1051/0004-6361/201015390

Cited by 34 publications

(50 citation statements)

References 67 publications

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“…Cavaliere et al 2011). For our clusters this would indeed imply values of ∼1−2 Mpc h −1 for the outer scale of turbulent motions, Λ, one order of magnitude larger than what we measure here.…”

Section: Turbulent Energy Budget In Clustersmentioning

confidence: 99%

Turbulence in the ICM from mergers, cool-core sloshing, and jets: results from a new multi-scale filtering approach

Vazza

Röediger

Brüggen

2012

A&A

104

101

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We have designed a simple multi-scale method that identifies turbulent motions in hydrodynamical grid simulations. The method does not assume any a priori coherence scale to distinguish laminar and turbulent flows. Instead, the local mean velocity field around each cell is reconstructed with a multi-scale filtering technique, yielding the maximum scale of turbulent eddies by means of iterations. The method is robust, fast, and easily applicable to any grid simulation. We present here the application of this technique to the study of spatial and spectral properties of turbulence in the intra-cluster medium, measuring turbulent diffusion and anisotropy of the turbulent velocity field for a variety of driving mechanisms: a) accretion of matter in galaxy clusters (simulated with ENZO); b) sloshing motions around cool-cores (simulated with FLASH); c) jet outflows from active galactic nuclei (AGN, simulated with FLASH). The turbulent velocities driven by matter accretion in galaxy clusters are mostly tangential in the inner regions (inside the cluster virial radius) and isotropic in regions close to the virial radius. The same is found for turbulence excited by cool-core sloshing, while the jet outflowing from AGN drives mostly radial turbulence motions near its sonic point and beyond. Turbulence leads to a diffusivity in the range D turb ∼ 10 29 −10 30 cm 2 s −1 in the intra-cluster medium. On average, the energetically dominant mechanism of turbulence driving in the intra cluster medium is represented by accretion of matter and major mergers during cluster evolution.

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Section: Turbulent Energy Budget In Clustersmentioning

confidence: 99%

Turbulence in the ICM from mergers, cool-core sloshing, and jets: results from a new multi-scale filtering approach

Vazza

Röediger

Brüggen

2012

A&A

104

101

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“…This hints towards a link between the SGS turbulence energy production in the WHIM and the gas accretion on shocks associated with growing structures. Recently, Cavaliere, Lapi & Fusco‐Femiano (2011) investigated thoroughly the injection of turbulence in cluster outskirts (at the accretion shocks) with analytical calculations, finding that the turbulent support increases from z ∼ 0.5. In their analysis, this is due to the shock weakening, the decrease in accretion rates on clusters and the decrease in the gas infall speed at low redshift.…”

Section: Evolution Of the Whim And The Icmmentioning

confidence: 99%

Turbulence production and turbulent pressure support in the intergalactic medium

Iapichino

Schmidt

Niemeyer

et al. 2011

Monthly Notices of the Royal Astronomical Society

113

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The injection and evolution of turbulence in the intergalactic medium is studied by means of mesh‐based hydrodynamical simulations, including a subgrid‐scale (SGS) model for small‐scale unresolved turbulence. The simulations show that the production of turbulence has a different redshift dependence in the intracluster medium (ICM) and the warm‐hot intergalactic medium (WHIM). We show that the turbulence in the ICM is produced chiefly by merger‐induced shear flows, whereas the production in the WHIM is dominated by shock interactions. Secondly, the effect of dynamical pressure support on the gravitational contraction has been studied. This turbulent support is stronger in the WHIM gas at baryon overdensities 1 ≲δ≲ 100 and less relevant for the ICM. Although the relative mass fraction of the gas with large vorticity is considerable (52 per cent in the ICM), we find that for only about 10 per cent in mass this is dynamically relevant, namely not associated with an equally large thermal pressure support. According to this result, a significant non‐thermal pressure support counteracting the gravitational contraction is a localized characteristic in the cosmic flow, rather than a widespread feature.

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“…The accretion shocks thermalize the majority of the kinetic energy acquired by the gas during infall. Recent work suggests, however, that this mechanism does not result in complete virialization and that some fraction of the kinetic energy remains in bulk and turbulent flow of the ICM (Cavaliere et al 2011). These bulk and turbulent flows contribute to the support of the ICM against gravity, in the same way as thermal pressure, and thus such contributions are termed "nonthermal pressure."…”

Section: Introductionmentioning

confidence: 99%

Constraints on the Mass, Concentration, and Nonthermal Pressure Support of Six CLASH Clusters from a Joint Analysis of X-Ray, SZ, and Lensing Data

Siegel

Sayers

Mahdavi

et al. 2018

ApJ

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We present a joint analysis of Chandra X-ray observations, Bolocam thermal Sunyaev-Zel'dovich (SZ) effect observations, Hubble Space Telescope (HST) strong-lensing data, and HST and Subaru Suprime-Cam weak-lensing data. The multiwavelength data set is used to constrain parametric models for the distribution of dark and baryonic matter in a sample of six massive galaxy clusters selected from the Cluster Lensing And Supernova survey with Hubble (CLASH). For five of the six clusters, the multiwavelength data set is well described by a relatively simple model that assumes spherical symmetry, hydrostatic equilibrium, and entirely thermal pressure support. The joint analysis yields considerably better constraints on the total mass and concentration of the clusters compared to analysis of any one data set individually. The resulting constraints are consistent with simulation-based predictions for the concentration-mass relation. The subsample of five galaxy clusters is used to place an upper limit on the fraction of pressure support in the intracluster medium (ICM) due to nonthermal processes, such as turbulence and bulk flow of the gas. We constrain the nonthermal pressure fraction at r 500c to be <0.11 at 95% confidence. This is in tension with state-of-the-art hydrodynamical simulations, which predict a nonthermal pressure fraction of ≈0.25 at r 500c for clusters of similar mass and redshift. This tension may be explained by the sample selection and/or our assumption of spherical symmetry.

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Nonthermal support for the outer intracluster medium

Cited by 34 publications

References 67 publications

Turbulence in the ICM from mergers, cool-core sloshing, and jets: results from a new multi-scale filtering approach

Turbulence in the ICM from mergers, cool-core sloshing, and jets: results from a new multi-scale filtering approach

Turbulence production and turbulent pressure support in the intergalactic medium

Constraints on the Mass, Concentration, and Nonthermal Pressure Support of Six CLASH Clusters from a Joint Analysis of X-Ray, SZ, and Lensing Data

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