Richness Dependence of the Recent Evolution of Clusters of Galaxies
arXiv:0901.2035 · doi:10.1111/j.1365-2966.2009.14507.x
Abstract
We revisit the issue of the recent dynamical evolution of clusters of galaxies using a sample of ACO clusters with z<0.14, which has been selected such that it does not contain clusters with multiple velocity components nor strongly merging or interacting clusters, as revealed in X-rays. We use as proxies of the cluster dynamical state the projected cluster ellipticity, velocity dispersion and X-ray luminosity. We find indications for a recent dynamical evolution of this cluster population, which however strongly depends on the cluster richness. Poor clusters appear to be undergoing their primary phase of virialization, with their ellipticity increasing with redshift with a rate de/dz ~ 2.5, while the richest clusters show an ellipticity evolution in the opposite direction (with de/dz ~ -1.2), which could be due to secondary infall. When taking into account sampling effects due to the magnitude-limited nature of the ACO cluster catalogue we find no significant evolution of the cluster X-ray luminosity, while the velocity dispersion increases with decreasing redshift, independent of the cluster richness, at a rate dsigma/dz ~ -1700 km/sec.
10 pages, MNRAS in press
References in corpus (6)
- The spin and shape of dark matter haloes in the Millennium simulation of a LambdaCDM universe
- Radial temperature profiles for a large sample of galaxy clusters observed with XMM-Newton
- Infall caustics in dark matter halos?
- Secondary infall and dark matter haloes
- Robust quantitative measures of cluster X-ray morphology, and comparisons between cluster characteristics
- Environmental Influences on the Morphology and Dynamics of Group Size Haloes