Related papers: Explaining the entropy excess in clusters and grou…
This contribution illustrates the study of galaxy clusters as astrophysical laboratories as well as probes for the large-scale structure of the Universe. Using the REFLEX Cluster Survey, the measurement of the statistics of the large-scale…
As an alternative explanation of the entropy excess and the steepening of the X-ray luminosity-temperature relation in groups and clusters, the galaxy formation-regulated gas evolution (GG) model proposed recently by Bryan makes an attempt…
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 investigate the properties of the intracluster medium (ICM) that forms within N-body/hydrodynamical simulations of galaxy clusters in a \LambdaCDM cosmology. When radiative cooling and a simple model for galactic feedback are included,…
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,…
Virialized systems, such as clusters and groups of galaxies, represent an ideal laboratory for investigating the formation and evolution of structure on the largest scales. Furthermore, the properties of the gaseous intracluster medium…
We study the X-ray cluster gas density distribution in hydrostatic equilibrium using the universal temperature profile obtained from recent simulations involving only gravitational processes. If this temperature profile is an indicator of…
The X-ray properties of a relaxed cluster of galaxies are determined primarily by its gravitational potential well and the entropy distribution of its intracluster gas. That entropy distribution reflects both the accretion history of the…
We use gas-dynamical simulations of galaxy clusters to compare their X-ray and strong lensing properties. Special emphasis is laid on mass estimates. The cluster masses range between 6 x 10^14 solar masses and 4 x 10^15 solar masses, and…
We examine profiles and scaling properties of the entropy of the intergalactic gas in a sample of 66 virialized systems, ranging in mass from single elliptical galaxies to rich clusters, for which we have resolved X-ray temperature…
We present a set of cluster models that link the present-day properties of clusters to the processes that govern galaxy formation. These models treat the entropy distribution of the intracluster medium as its most fundamental property.…
There has been extensive recent progress in X-ray observations of clusters of galaxies with the analysis of the entire ASCA database and recent new results from Beppo-SAX, Chandra, and XMM-Newton. The temperature profiles of most clusters…
Galaxy groups differ from clusters primarily by way of their lower masses, M~10^14 M_sun vs. M~10^15 M_sun. We discuss how mass affects the thermal state of the intracluster or the intragroup medium, specifically as to their entropy levels…
We investigate statistical properties of galaxy clusters in the context of hierarchical clustering scenario, taking account of their formation epoch distribution, motivated by the recent finding by Fujita and Takahara that X-ray clusters…
X-ray observations of hot gas in galaxy groups indicate higher entropies than can be achieved in the accretion shocks as it fell into the dark halos. It has been proposed that this entropy excess results from some universal external heating…
We study steady, homogeneous and subsonic cooling flows in poor clusters of galaxies in light of the recent proposal that radiative cooling of the intracluster gas can explain the observations of the `entropy floor' and other related X-ray…
We run adiabatic N-body/hydrodynamical simulations of isolated self-gravitating gas clouds to test whether conformal gravity, an alternative theory to General Relativity, is able to explain the properties of X-ray galaxy clusters without…
I review some important aspects of the structural and statistical properties of the nearby X-ray galaxy cluster population, discussing the new constraints on mass profiles, the mass-temperature relation, and the entropy of the intracluster…
We present results on the total mass and temperature determination using two samples of clusters of galaxies. One sample is constructed with emphasis on the completeness of the sample, while the advantage of the other is the use of 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…