Related papers: Radio Source Heating in the ICM: The Example of Cy…
We study the heating of the cool cores in galaxy clusters by cosmic-rays (CRs) accelerated by the central active galactic nuclei (AGNs). We especially focus on the stability of the heating. The CRs stream with Alfv\'en waves in the…
There is now firm evidence that the ICM consists of a mixture of hot plasma, magnetic fields and relativistic particles. The most important evidences for non-thermal phenomena in galaxy clusters comes from the diffuse Mpc-scale synchrotron…
Analyses of Chandra's first images of cooling flow clusters find smaller cooling rates than previously thought. Cooling may be occurring preferentially near regions of star formation in central cluster galaxies, where the local cooling and…
We present a detailed analysis of the thermal X-ray emission from the intracluster medium (ICM) in the cool-core galaxy cluster Abell 2667 ($z=0.23$). Our goal is to detect low-temperature ($<2$ keV) X-ray emitting gas, potentially…
Our understanding of how AGN feedback operates in galaxy clusters has improved in recent years owing to large efforts in multi-wavelength observations and hydrodynamical simulations. However, it is much less clear how feedback operates in…
Galaxy clusters are the most massive collapsed structures in the universe whose potential wells are filled with hot, X-ray emitting intracluster medium. Observations however show that a significant number of clusters (the so-called…
We present new Spitzer IRS spectroscopy of Cygnus A, one of the most luminous radio sources in the local universe. Data on the inner 20" are combined with new reductions of MIPS and IRAC photometry as well as data from the literature to…
We present an analysis of a Chandra ACIS-I observation of the massive galaxy cluster A644. This cluster was previously classified as a cooling flow, but no radio emission has been detected from its cD galaxy. Outside the core (R ~75 kpc…
We study intergalactic medium (IGM) heating in a sample of five fossil galaxy groups by using their radio properties at 610 MHz and 1.4 GHz. The power by radio jets introducing mechanical heating for the sampled objects is not sufficient…
Early X-ray observations suggested that the intracluster medium cools and condenses at the centers of clusters, leading to a cooling flow of plasma in the cluster core. The increased incidence of emission-line nebulosity, excess blue light,…
We present ASCA gas temperature maps of the nearby merging galaxy clusters Cygnus A, A3667, and A2065. Cygnus A appears to have a particularly simple merger geometry that allows an estimate of the subcluster collision velocity from the…
Almost every strong cooling core contains an active radio galaxy. Combined radio and X-ray images reveal the dramatic interaction which is taking place between the radio jet and the central cluster plasma. At least two important questions…
We present Chandra X-ray Observations of the Hydra A cluster of galaxies, and we report the discovery of structure in the central 80 kpc of the cluster's X-ray-emitting gas. The most remarkable structures are depressions in the X-ray…
We present the results of a Chandra study of the Hydra A galaxy cluster, where a powerful AGN outburst created a large-scale cocoon shock. We investigated possible azimuthal variations in shock strength and shape, finding indications for a…
A number of studies have shown that the convective stability criterion for the intracluster medium (ICM) is very different from the Schwarzchild criterion due to the effects of anisotropic thermal conduction and cosmic rays. Building on…
We have observed a new, complete, cooling-core sample with the VLA, in order to understand how the massive black hole in the central galaxy interacts with the local cluster plasma. We find that every cooling core is currently being…
Radio mini-halos are perplexing features, typically hosted by X-ray cool-core galaxy clusters. Understanding the connection between thermal X-ray and non-thermal radio emission is key to uncovering their origin. Here, we present a…
The composition of the relativistic plasma produced in active galactic nuclei and ejected via powerful jets into the interstellar/intergalactic medium is still a major unsettled issue. It might be a positron-electron plasma in case the…
Deep Chandra observations of the Hydra A Cluster reveal a feature in the X-ray surface brightness that surrounds the 330 MHz radio lobes of the AGN at the cluster center. Surface brightness profiles of this feature and its close association…
I argue that the mixing-heating mechanism of the intracluster medium (ICM) is compatible with the new observations by the X-ray telescope XRISM that show the dispersion velocity in the cooling flow cluster of galaxies A2029 to be 169 km/s.…