Related papers: Could AGN Outbursts Transform Cool Core Clusters?
Three comments are made on AGN heating of cooling flows. A simple physical argument is used to show that the enthalpy of a buoyant radio lobe is converted to heat in its wake. Thus, a significant part of ``cavity'' enthalpy is likely to end…
Active galactic nucleus (AGN) jets are believed to be important in solving the cooling flow problem in the intracluster medium (ICM), while the detailed mechanism is still in debate. Here we present a systematic study on the energy coupling…
Galaxy clusters are filled with hot, diffuse X-ray emitting plasma, with a stochastically tangled magnetic field whose energy is close to equipartition with the energy of the turbulent motions \cite{zweibel1997, Vacca}. In the cluster…
Observations of galaxy-cluster cores reveal that AGN feedback is strongly associated with both a short central cooling time ($t_{\rm c} \lesssim 10^9 \, {\rm yr}$) and accumulations of cold gas ($\lesssim 10^4 \, {\rm K}$). Also, the…
Central peaks in the iron abundance of intracluster plasma are a common feature of cooling-core galaxy clusters. These abundance peaks have a much broader profile than the stars of the central brightest cluster galaxy (BCG), which produce…
High resolution X-ray spectroscopy of the hot gas in galaxy clusters has shown that the gas is not cooling to low temperatures at the predicted rates of hundreds to thousands of solar masses per year. X-ray images have revealed giant…
We investigate the thermodynamic and chemical structure of the intracluster medium (ICM) across a statistical sample of 20 galaxy clusters analysed with the Chandra X-ray satellite. In particular, we focus on the scaling properties of the…
We investigate the role of AGN feedback in turbulent heating of galaxy clusters. Specifically, we analyze the production of turbulence by g-modes generated by the supersonic expansion and buoyant rise of AGN-driven bubbles. Previous work…
Heating from active galactic nuclei (AGN) is thought to stabilize cool-core clusters, limiting star formation and cooling flows. We employ radiative magneto-hydrodynamic (MHD) simulations to model light AGN jet feedback with different…
We present a simple analytical model and the results of numerical simulations supporting the idea of periodical heating of cluster gas by AGN outflows. We show why, under this assumption, we are extremely unlikely to observe clusters…
The Fornax Cluster is a low-mass cool-core galaxy cluster. We present a deep {\sl Chandra} study of NGC 1399, the central dominant elliptical galaxy of Fornax. The cluster center harbors two symmetric X-ray cavities coincident with a pair…
Several galaxy clusters are known to present multiple and misaligned pairs of cavities seen in X-rays, as well as twisted kiloparsec-scale jets at radio wavelengths. It suggests that the AGN precessing jets play a role in the formation of…
It is generally argued that most clusters of galaxies host cooling flows in which radiative cooling in the centre causes a slow inflow. However, recent observations by Chandra and XMM conflict with the predicted cooling flow rates. Amongst…
We discuss hydrostatic models of galaxy clusters in which heat diffusion balances radiative cooling. We consider two different sources of diffusion, thermal conduction and turbulent mixing, parameterized by dimensionless coefficients, f and…
Active galactic nuclei (AGN) release a huge amount of energy into the intracluster medium (ICM) with the consequence of offsetting cooling and star formation (AGN feedback) in the centers of cool core clusters. The Phoenix cluster is among…
There is growing consensus that feedback from AGN is the main mechanism responsible for stopping cooling flows in clusters of galaxies. AGN are known to inflate buoyant bubbles that supply mechanical power to the intracluster gas (ICM).…
Most cool core clusters of galaxies possess active galactic nuclei (AGN) in their centers. These AGN inflate buoyant bubbles containing non-thermal radio emitting particles. If such bubbles efficiently confine cosmic rays (CR) then this…
We investigate a numerical model for AGN feedback where for the first time a relativistic particle population in AGN-inflated bubbles is followed within a full cosmological context. In our high-resolution simulations of galaxy cluster…
The feedback from active galactic nuclei (AGN) plays a crucial role in regulating the thermodynamics and the dynamics of the intracluster medium (ICM). Studying the turbulent patterns of the hot and warm ionized phases may allow us to…
We emphasise the importance of the gas entropy in studying the evolution of cluster gas evolving under the influence of radiative cooling. On this basis, we develop an analytical model for this evolution. We then show that the assumptions…