The X-ray cluster normalization of the matter power spectrum.
HENRY J.P., EVRARD A.E., HOEKSTRA H., BABUL A. and MAHDAVI A.
Abstract (from CDS):
The number density of galaxy clusters provides tight statistical constraints on the matter fluctuation power spectrum normalization, traditionally phrased in terms of σ8, the root-mean-square mass fluctuation in spheres with radius 8 h.–1 Mpc. We present constraints on σ8 and the total matter density Ωm0 from local cluster counts as a function of X-ray temperature, taking care to incorporate and minimize systematic errors that plagued previous work with this method. In particular, we present new determinations of the cluster luminosity-temperature and mass-temperature relations, including their intrinsic scatter, and a determination of the Jenkins mass function parameters for the same mass definition as the mass-temperature calibration. Marginalizing over the 12 uninteresting parameters associated with this method, we find that the local cluster temperature function implies σ8(Ωm0/0.32)α = 0.86±0.04 with α = 0.30 and 0.41 for Ωm0≤ 0.32 and Ωm0≥ 0.32, respectively (68% confidence for two parameters). This result agrees with a wide range of recent independent determinations, and we find no evidence of any additional sources of systematic error for the X-ray cluster temperature function determination of the matter power spectrum normalization. The joint WMAP5 + cluster constraints are Ωm0 = 0.30+0.03–0.02 and σ8= 0.85+0.04–0.02(68% confidence for two parameters).
cosmological parameters - cosmology: observations - galaxies: clusters: general - large-scale structure of universe - X-rays: galaxies