title: Turbulent heating in galaxy clusters brightest in X-rays.
abstract: The hot (10(7) to 10(8) kelvin), X-ray-emitting intracluster medium (ICM) is the dominant baryonic constituent of clusters of galaxies. In the cores of many clusters, radiative energy losses from the ICM occur on timescales much shorter than the age of the system. Unchecked, this cooling would lead to massive accumulations of cold gas and vigorous star formation, in contradiction to observations. Various sources of energy capable of compensating for these cooling losses have been proposed, the most promising being heating by the supermassive black holes in the central galaxies, through inflation of bubbles of relativistic plasma. Regardless of the original source of energy, the question of how this energy is transferred to the ICM remains open. Here we present a plausible solution to this question based on deep X-ray data and a new data analysis method that enable us to evaluate directly the ICM heating rate from the dissipation of turbulence. We find that turbulent heating is sufficient to offset radiative cooling and indeed appears to balance it locally at each radius-it may therefore be the key element in resolving the gas cooling problem in cluster cores and, more universally, in the atmospheres of X-ray-emitting, gas-rich systems on scales from galaxy clusters to groups and elliptical galaxies.
authors.affiliation: 1] Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, 452 Lomita Mall, Stanford, California 94305-4085, USA [2] Department of Physics, Stanford University, 382 Via Pueblo Mall, Stanford, California 94305-4060, USA.
authors.forename: I
authors.initials: I
authors.lastname: Zhuravleva
authors.affiliation: 1] Max Planck Institute for Astrophysics, Karl-Schwarzschild-Strasse 1, D-85741 Garching, Germany [2] Space Research Institute (IKI), Profsoyuznaya 84/32, Moscow 117997, Russia.
authors.forename: E
authors.initials: E
authors.lastname: Churazov
authors.affiliation: 1] Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Rd, Oxford OX1 3NP, UK [2] Merton College, University of Oxford, Merton St, Oxford OX1 4JD, UK.
authors.forename: A A
authors.initials: AA
authors.lastname: Schekochihin
authors.affiliation: 1] Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, 452 Lomita Mall, Stanford, California 94305-4085, USA [2] Department of Physics, Stanford University, 382 Via Pueblo Mall, Stanford, California 94305-4060, USA [3] SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
authors.forename: S W
authors.initials: SW
authors.lastname: Allen
authors.affiliation: 1] Instituto de Física y Astronomía, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretana N 1111, Playa Ancha, Valparaíso, Chile [2] Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, 306, Santiago 22, Chile.
authors.forename: P
authors.initials: P
authors.lastname: Arévalo
authors.affiliation: Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK.
authors.forename: A C
authors.initials: AC
authors.lastname: Fabian
authors.affiliation: Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138, USA.
authors.forename: W R
authors.initials: WR
authors.lastname: Forman
authors.affiliation: Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching, Germany.
authors.forename: J S
authors.initials: JS
authors.lastname: Sanders
authors.affiliation: Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 252-5210, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Simionescu
authors.affiliation: 1] Max Planck Institute for Astrophysics, Karl-Schwarzschild-Strasse 1, D-85741 Garching, Germany [2] Space Research Institute (IKI), Profsoyuznaya 84/32, Moscow 117997, Russia.
authors.forename: R
authors.initials: R
authors.lastname: Sunyaev
authors.affiliation: Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138, USA.
authors.forename: A
authors.initials: A
authors.lastname: Vikhlinin
authors.affiliation: 1] Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, 452 Lomita Mall, Stanford, California 94305-4085, USA [2] Department of Physics, Stanford University, 382 Via Pueblo Mall, Stanford, California 94305-4060, USA.
authors.forename: N
authors.initials: N
authors.lastname: Werner