Related papers: Constraining the Matter Power Spectrum Normalizati…
We present a lensing study of 42 galaxy clusters imaged in Sloan Digital Sky Survey (SDSS) commissioning data. Cluster candidates are selected optically from SDSS imaging data and confirmed for this study by matching to X-ray sources found…
In this work, we use two gas mass fraction samples of galaxy clusters obtained from their X-ray surface brightness observations jointly with recent $H(z)$ data in a flat $\Lambda$CDM framework to impose limits on cosmic opacity. It is…
New observational constraints on the cosmic matter density $\Omega_m$ and an effectively redshift-independent equation of state parameter $w_x$ of the dark energy are obtained while simultaneously testing the strong and null energy…
Recent studies have shown that the cross-correlation coefficient between galaxies and dark matter is very close to unity on scales outside a few virial radii of galaxy halos, independent of the details of how galaxies populate dark matter…
From the Press-Schechter mass function and the empirical X-ray cluster luminosity-temperature (L-T) relation, we construct an X-ray cluster luminosity function that can be applied to the growing number of high-redshift, X-ray cluster…
The clustering of X-ray selected AGN appears to be a valuable tool for extracting cosmological information. Using the recent high-precision angular clustering results of ~30000 XMM-Newton soft (0.5-2 keV) X-ray sources (Ebrero et al. 2009),…
Stringent observational constraints on the sub-galactic matter power spectrum would allow one to distinguish between the concordance $\Lambda$CDM and the various alternative dark-matter models that predict significantly different properties…
We combine the measurements of luminosity dependence of bias with the luminosity dependent weak lensing analysis of dark matter around galaxies to derive the galaxy bias and constrain nonlinear mass and cosmological parameters. We take…
We present a survey of mass profiles and mass-to-light ratios of eight typical galaxy clusters at a common redshift (z ~ 0.2). We use weak gravitational lensing as a probe because it is unique in avoiding any assumptions about the dynamical…
[Abridged] We use data on massive galaxy clusters ($M_{\rm cluster} > 8 \times 10^{14} h^{-1} M_\odot$ within a comoving radius of $R_{\rm cluster} = 1.5 h^{-1}\Mpc$) in the redshift range $0.05 \lesssim z \lesssim 0.83$ to place…
We show how redshift-space distortions of the galaxy correlation function or power spectrum can constrain the matter density parameter Omega_m and the linear matter fluctuation amplitude sigma_8. We improve on previous treatments by…
We determine the linear amplitude of mass fluctuations in the universe, sigma_8, from the abundance of massive clusters at redshifts z=0.5 to 0.8. The evolution of massive clusters depends exponentially on the amplitude of mass fluctuations…
We study the amplitude of the weak gravitational lensing signal as a function of stellar mass around a sample of relatively isolated galaxies. This selection of lenses simplifies the interpretation of the observations, which consist of data…
We present constraints on the mean matter density, Omega_m, dark energy density, Omega_de, and the dark energy equation of state parameter, w, using Chandra measurements of the X-ray gas mass fraction (fgas) in 42 hot (kT>5keV), X-ray…
Scaling relations of observed galaxy cluster properties are useful tools for constraining cosmological parameters as well as cluster formation histories. One of the key cosmological parameters, sigma8, is constrained using observed clusters…
Measurements of the growth rate of structure, $f\sigma_8$ in the low-redshift Universe allow stringent tests of the cosmological model. In this work, we provide new constraints on $f\sigma_{8}$ at an effective redshift of $z=0.03$ using the…
The constraints obtained by several authors (Eke et al. 1998; Henry 2000) on the estimated values of $\Omega_{\rm m}$, $n$ and $\sigma_8$ are revisited in the light of recent theoretical developments: 1) new theoretical mass functions; 2) a…
We analyse parallel N-body simulations of three Cold Dark Matter (CDM) universes to study the abundance and clustering of galaxy clusters. The simulations cover a volume comparable to the forthcoming SDSS. We are able to make robust…
We present a new geometrical method which uses weak gravitational lensing effects in clusters to constrain the cosmological parameters Omega and Lambda. On each background galaxy, a cluster induces a convergence and a shear terms, which…
The CNOC redshift survey of galaxy clusters measures Omega_M from Omega_e(z)= M/L x j/\rho_c which can be applied on a cluster-by-cluster basis. The mass-to-light ratios, M/L, are estimated from rich galaxy clusters, corrected to the field…