Related papers: X-ray Cavities and Cooling Flows
Recent observations of the interactions between radio sources and the X-ray-emitting gas in cooling flows in the cores of clusters of galaxies are reviewed. The radio sources inflate bubbles in the X-ray gas, which then rise buoyantly…
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…
Chandra images of galaxy clusters have revealed a wealth of structure unseen by previous generations of low resolution X-ray observatories. In the cores of clusters, bright, irregular X-ray emission is now routinely seen within central…
As more cooling flow clusters of galaxies with central radio sources are observed with the Chandra and XMM-Newton X-ray Observatories, more examples of "bubbles" (low-emission regions in the X-ray coincident with radio emission) are being…
We describe the formation and evolution of X-ray cavities in the hot gas of galaxy clusters. The cavities are formed only with relativistic cosmic rays that eventually diffuse into the surrounding gas. We explore the evolution of cavities…
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 discuss new results from the Chandra X-ray Observatory and XMM-Newton on cluster cooling flows, emphasizing early results from our Chandra programs. We find cooling rates reduced by factors of 5-10 compared to those from earlier…
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 X-ray emission in many clusters of galaxies shows a central peak in surface brightness coincident with a drop in temperature. These characterize a cooling flow. There is often a radio source also at the centre of such regions. Data from…
We present an analysis of sixteen galaxy clusters, one group and one galaxy drawn from the Chandra X-ray Observatory's data archive. These systems possess prominent X-ray surface brightness depressions associated with cavities or bubbles…
We study the possibility that a large fraction of the gas at temperatures of \~10^7 K in cooling flow clusters cools by heat conduction to lower temperatures, rather than by radiative cooling. We argue that this process, when incorporated…
The hot plasma permeating clusters of galaxies often shows a central peak in the X-ray surface brightness that is coincident with a drop in entropy. This is taken as evidence for a cooling flow where the radiative cooling in the central…
The radiative cooling time of the X-ray-emitting plasma near the center in many clusters of galaxies is shorter than the age of the cluster, but neither the expected large drop in central temperature --nor the expected mass flow towards the…
Two lines of evidence indicate that active galaxies, principally radio galaxies, have heated the diffuse hot gas in clusters. The first is the general need for additional heating to explain the steepness of the X-ray luminosity--temperature…
A common feature of the X-ray bubbles observed in Chandra images of some "cooling flow" clusters is that they appear to be surrounded by bright, cool shells. Temperature maps of a few nearby luminous clusters reveal that the shells consist…
We propose a scenario in which a large fraction, or even most, of the gas cooling to low temperatures of T<10^4 K in cooling flow clusters, directly gains energy from the central black hole. Most of the cool gas is accelerated to…
Expanding X-ray cavities observed in hot gas atmospheres of many galaxy groups and clusters generate shock waves and turbulence that are primary heating mechanisms required to avoid uninhibited radiatively cooling flows which are not…
The gas in the cores of many clusters and groups of galaxies has a short radiative cooling time. Energy from the central black hole is observed to flow into this gas by means of jets, bubbles and sound waves. Cooling is thus offset by…
The density irregularities and holes visible in many Chandra X-ray images of cluster and galactic cooling flows can be produced by symmetrically heated gas near the central galactic black hole. As the heated gas rises away from the galactic…
Over the past several years, numerous examples of X-ray cavities coincident with radio sources have been observed in so-called "cool core" clusters of galaxies. Motivated by these observations, we explore the evolution and the effect of…