Related papers: Testing minimum energy with powerful radio sources…
The synchrotron-radiating particles and magnetic fields in low-power radio galaxies (including most nearby cluster-centre sources), if at equipartition, can provide only a small fraction of the total internal energy density of the radio…
Results are presented of a new VLA-ROSAT study that probes the magnetic field strength and distribution over a sample of 16 ``normal'' low redshift (z < 0.1) galaxy clusters. The clusters span two orders of magnitude in X-ray luminosity,…
We examine the remnant phase of radio galaxies using three-dimensional hydrodynamical simulations of relativistic jets propagating through cluster environments. By switching the jets off once the lobes have reached a certain length we can…
We have carried out two-dimensional, axisymmetric, hydrodynamic numerical modelling of the evolution of radio galaxy lobes. The emphasis of our work is on including realistic hot-gas environments in the simulations and on establishing what…
The interactions between low-power radio galaxies and their environments are thought to play a crucial role in supplying energy to offset cooling in the centres of groups and clusters. Such interactions are also important in determining…
We study the impact of cluster environment on the morphology of a sample of 4304 extended radio galaxies from Radio Galaxy Zoo. A total of 87% of the sample lies within a projected 15 Mpc of an optically identified cluster. Brightest…
We present results from two suites of simulations of powerful radio galaxies in poor cluster environments, with a focus on the formation and evolution of the radio lobes. One suite of models uses relativistic hydrodynamics and the other…
We investigate the properties of the environment around 20 powerful radio galaxies and quasars at redshifts between 0.45 and 1. Using XMM-Newton and Chandra observations we probe the spatial distribution and the temperature of the cluster…
Recent results on cluster cooling flows are reviewed. Observations of excess soft X-ray provides the only direct evidence for a major repository for the cooled gas. Unfortunately, the frequency of occurrence of large excess columns is…
The time- and ensemble-averaged mechanical energy outputs of radio galaxies may be large enough to offset much of the cooling inferred from X-ray observations of galaxy clusters. But does this heating actually counterbalance the cooling,…
We present a combined radio/X-ray study of six massive galaxy clusters, aimed at determining the potential for heating of the intra-cluster medium (ICM) by non-central radio galaxies. Since X-ray cavities associated with the radio lobes of…
The brightest cluster galaxy (BCG) in the majority of relaxed, cool core galaxy clusters is radio loud, showing non-thermal radio jets and lobes ejected by the central active galactic nucleus (AGN). Such relativistic plasma has been…
The masses of clusters of galaxies estimated by gravitational lensing exceed in many cases the mass estimates based on hydrostatic equilibrium. This may suggest the existence of nonthermal pressure. We ask if radio galaxies can heat and…
The evidence for the presence of a concentration of dark matter at the Galactic center is now very compelling. There is no question that the stellar and gas kinematics within 0.01 pc is dominated by under-luminous matter in the form of…
The radio properties of powerful extended radio sources may be used to estimate the ambient gas density in the vicinity of radio lobes. A sample of 27 radio lobes from 14 radio galaxies and of 14 radio lobes from 8 radio loud quasars was…
Bent radio AGN morphology depends on the density of the surrounding gas. However, bent sources are found inside and outside clusters, raising the question of how environment impacts bent AGN morphology. We analyze new LOw-Frequency Array…
The recent evidences of the presence of magnetic fields and relativistic particles in galaxy clusters are reviewed. The existence of microG-level magnetic fields in cluster atmospheres appears well established from the detection of diffuse…
The number of observed giant radio sources (GRSs) has increased significantly in recent years, yet their formation mechanisms remain elusive. The discovery of giant radio galaxies within galaxy clusters has further intensified the ongoing…
(Abridged) The prevalence of radio-loud AGN activity in present-day massive halos is determined using a sample of 625 nearby groups and clusters from the SDSS. Brightest group and cluster galaxies (BCGs) are more likely to host a radio-loud…
We argue that, when compared to AGNs in dynamical terms, microquasars are found in low density, low pressure environments. Using a simple analytic model, we discuss radio lobe dynamics and emission. Dynamical considerations for GRS 1915+105…