Related papers: The Dynamical Equilibrium of Galaxy Clusters
Dynamic velocity dispersion and mass estimates are given for a sample of five X-ray luminous rich clusters of galaxies at intermediate redshifts (z~0.3) drawn from a sample of 39 clusters for which we have obtained gravitational lens mass…
This study presents highly precise measurements of the cross-correlation between volume-limited galaxy samples from the DESI legacy survey catalogue and X-ray selected galaxy clusters from eROSITA, allowing for detailed analysis across…
The population and population composition of galaxies in galaxy clusters at present reflect the mass of the clusters and the mass growth of the galaxies in the past. We investigate them for six clusters. We show that galaxies in massive…
We present an algorithm for inferring the dynamical mass of galaxy clusters directly from their respective phase-space distributions, i.e. the observed line-of-sight velocities and projected distances of galaxies from the cluster centre.…
We use simulated galaxy surveys to study: i) how galaxy membership in redMaPPer clusters maps to the underlying halo population, and ii) the accuracy of a mean dynamical cluster mass, $M_\sigma(\lambda)$, derived from stacked pairwise…
We study the role of group infall in the assembly and dynamics of galaxy clusters in $\Lambda$CDM. We select $10$ clusters with virial mass $M_{\rm 200} \sim 10^{14} \, M_{\odot}$ from the cosmological hydrodynamical simulation Illustris…
A comparative analysis of the dynamics of the orbital motion (regular or chaotic) of 45 globular clusters in the central region of the Galaxy with a radius of 3.5 kpc is carried out. The static and evolving (based on the semi-analytical…
An extensive redshift survey has been conducted on a sample of 15 nearby (0.01 < z < 0.05) clusters of galaxies. A total number of 860 redshifts were determined by fitting of emission--lines and/or cross-correlation techniques. Of this…
We discuss the development and physics of the cosmic virial theorem and its traditional application as an indicator of the cosmic mean density. The standard result that the density must be sub-critical relies on the assumption that the…
Star clusters are observed to form in a highly compact state and with low star-formation efficiencies. If the residual gas is expelled on a dynamical time the clusters disrupt thereby (i) feeding a hot kinematical stellar component into…
Velocity dispersions have been employed as a method to measure masses of clusters. To complement this conventional method, we explore the possibility of constraining cluster masses from the stacked phase space distribution of galaxies at…
We examine the dynamics of the stars and globular clusters in the nearby giant galaxy M87 and constrain the mass distribution, using all the available data over a large range of radii, including higher-order moments of the stellar…
Shells in Elliptical Galaxies are faint, sharp-edged features, believed to provide evidence of a recent ($\sim 0.5 - 2 \times 10^9$ years ago) merger event. We analyse the Globular Cluster (GC) systems of six shell elliptical galaxies, to…
Although numerous studies of individual galaxy clusters have demonstrated the presence of significant substructure, previous studies of the distribution of masses of galaxy clusters determined from optical observations have failed to…
We use cosmological gas dynamic simulations to investigate the accuracy of galaxy cluster mass estimates based on X-ray observations. The experiments follow the formation of clusters in different cosmological models and include the effects…
According to the cosmological principle, galaxy cluster sizes and cluster densities, when averaged over sufficiently large volumes of space, are expected to be constant everywhere, except for a slow variation with look-back time (redshift).…
Many young extra-galactic clusters have a measured velocity dispersion that is too high for the mass derived from their age and total luminosity, which has led to the suggestion that they are not in virial equilibrium. Most of these…
It is shown that the number of members, $N_A$, and the linear radius of the Abell clusters at $z<0.18$ increase with redshift. The increase is caused by observational selection: the number of rich and large clusters is small in the nearby…
There has been plenty of observational evidence of cluster galaxy evolution. However, it has been difficult to identify the origin of the cluster galaxy evolution. Here we show that gravitational interaction/friction between galaxies is the…
The kinematics of newly-formed star clusters are interesting both as a probe of the state of the gas clouds from which the stars form, and because they influence planet formation, stellar mass segregation, cluster disruption, and other…