Regulation of thermal conductivity in hot galaxy clusters by MHD turbulence

Abstract

The role of thermal conduction in regulating the thermal behavior of cooling flows in galaxy clusters is reexamined. Recent investigations have shown that the anisotropic Coulomb heat flux caused by a magnetic field in a dilute plasma drives a dynamical instability. A long standing problem of cooling flow theory has been to understand how thermal conduction can offset radiative core losses without completely preventing them. In this Letter we propose that magnetohydrodynamic turbulence driven by the heat flux instability regulates field-line insulation and drives a reverse convective thermal flux, both of which may mediate the stabilization of the cooling cores of hot clusters. This model suggests that turbulent mixing should accompany strong thermal gradients in cooling flows. This prediction seems to be supported by the spatial distribution of metals in the central galaxies of clusters, which shows a much stronger correlation with the ambient hot gas temperature gradient than with the parent stellar population.

4 Pages. Accepted for publication in Astrophysical Journal Letters

References in corpus (8)

• A Catalog of Galaxy Clusters Observed by XMM-Newton
• On the prevalence of radio-loud AGN in brightest cluster galaxies: implications for AGN heating of cooling flows
• Buoyancy Instabilities in Weakly Magnetized Low Collisionality Plasmas
• A Chandra archival study of the temperature and metal abundance profiles in hot Galaxy Clusters at 0.1 < z < 0.3
• Nonlinear Simulations of the Heat Flux Driven Buoyancy Instability and its Implications for Galaxy Clusters
• Saturation of the Magnetothermal Instability in Three Dimensions
• Thermal Balance in the Intracluster Medium: Is AGN Feedback Necessary?
• Convection and AGN Feedback in Clusters of Galaxies

Cited by in corpus (9)

• Anisotropic Thermal Conduction and the Cooling Flow Problem in Galaxy Clusters
• The Magnetothermal Instability in the Intracluster Medium
• Simulations of MHD Instabilities in Intracluster Medium Including Anisotropic Thermal Conduction
• Cooling flow regime of a plasma thermal quench
• Collisionless conduction in a high-beta plasma: a collision operator for whistler turbulence
• The Evaporation and Survival of Cluster Galaxies' Coronae Part II: The Effectiveness of Anisotropic Thermal Conduction and Survival of Stripped Galactic Tails
• Does the magneto-thermal instability survive whistler-suppression of thermal conductivity in galaxy clusters?
• Electron heat flux and propagating fronts in plasma thermal quench via ambipolar transport
• Two-Loop Turbulent Helical Magnetohydrodynamics: Large-Scale Dynamo and Energy Spectrum