Related papers: On Galaxy-Cluster Sizes and Temperatures
The evolution with redshift of the temperature-luminosity relation of X-ray galaxy clusters is a key ingredient to break degeneracies in the interpretation of X-ray clusters redshift number counts. We therefore take advantage of the recent…
Precision cosmology studies based on wide-field surveys of galaxy clusters benefit from constraints on intrinsic scatter in mass-observable relationships. In principle, two-parameter models combining direct measurements of galaxy cluster…
Much evidence suggests that we live in a flat Cold Dark Matter universe with a cosmological constant. Accurate analytic formulae are now available for many properties of the dark halo population in such a Universe. Assuming current…
The existence of the three most massive clusters of galaxies observed so far at z>0.5 is used to constrain the mass density parameter of the universe, Omega, and the amplitude of mass fluctuations, sigma_8. We find Omega=0.2 (+0.3,-0.1),…
We investigate the interactions of high-redshift galaxy outflows with low-mass virialized (Tvir < 10,000K) clouds of primordial composition. While atomic cooling allows star formation in larger primordial objects, such "minihalos" are…
We present XMM-Newton results on the spatially resolved temperature profiles of eight massive galaxy clusters of a volume-limited sample at redshifts $z\sim0.3$ (REFLEX-DXL sample) and an additional luminous cluster at $z=0.2578$, selected…
The thermal properties of hydrodynamical simulations of galaxy clusters are usually compared to observations by relying on the emission-weighted temperature T_ew, instead of on the spectroscopic X-ray temperature T_spec, which is obtained…
Many approaches to obtaining cosmological constraints rely on the connection between galaxies and dark matter. However, the distribution of galaxies is dependent on their formation and evolution as well as the cosmological model, and galaxy…
We investigate the clustering of galaxy groups and clusters in the SDSS using the Berlind et al. (2006) group sample, which is designed to identify galaxy systems that each occupy a single dark matter halo. We estimate group masses from…
I derive the mass-temperature relation and its time evolution for clusters of galaxies in different cosmologies by means of two different models. The first one is a modification and improvement of a model by Del Popolo & Gambera(1999),…
We present a self-consistent approach to the modeling of X-ray clusters of galaxies in a flat universe. Employing the Press and Schechter (1974) formalism to derive the mass function and relating the observable properties of clusters to…
The concentrations of the cuspy dark matter halos predicted by simulations of cold dark matter are related to the cosmology in which the halos form. Observational constraints on halo concentration therefore map into constraints on…
The aim of the present work is to show that, contrary to popular belief, galaxy clusters are **not** expected to be self-similar, even when the only energy sources available are gravity and shock-wave heating. In particular, we investigate…
We propose a novel component to the understanding of the temperature structure of galaxy clusters which does not rely on any heating or cooling mechanism. The new ingredient is the use of non-extensive thermo-statistics which is based on…
The thermodynamic properties of the hot plasma in galaxy clusters retains information on the processes leading to the formation and evolution of the gas in their deep, dark matter potential wells. These processes are dictated not only by…
We place constraints on the average density (Omega_m) and clustering amplitude (sigma_8) of matter using a combination of two measurements from the Sloan Digital Sky Survey: the galaxy two-point correlation function, w_p, and the…
We use a very large simulation of structure growth in a LCDM universe -- the Millennium Simulation -- to study assembly bias, the fact that the large-scale clustering of haloes of given mass varies significantly with their assembly history.…
We analyzed the luminosity-temperature-mass of gas (L_{X} - T - M_{g}) relation for sample of galaxy clusters that have been observed by the Chandra satellite. We used 21 high-redshift clusters (0.4 < z < 1.4). We assumed a power-law…
A simple model for a hot Local Group halo is constructed, using the standard beta-model for the halo density and by choosing model parameters based on all available observations of X-ray emission in other groups of galaxies and on optical…
The relationship between the X-ray determined temperature $T$ of the intracluster gas and the optical measured velocity dispersion $\sigma$ of the cluster galaxies is often believed to be not only a straightforward but also robust test for…