Measuring Cosmological Parameters from the Evolution of Cluster X‐Ray Temperatures

Abstract

We have determined the cluster X-ray temperature function from two Ñux-and redshift-limited samples of clusters. The Ðrst sample is comprised of 25 clusters with average redshift 0.05. The local temperature function derived from it supersedes the one we published previously. Fourteen clusters with average redshift 0.38 comprise the second sample. We perform maximum likelihood Ðts of cluster evolution models to these data in order to constrain cosmological parameters. For an open model with zero cosmological constant we Ðnd that the density parameter is the rms mass density Ñuc-) 0 \ 0.49^0.12, tuation averaged over 8 h~1 Mpc spheres is and the e †ective index of the mass density p 8 \ 0.72^0.10, Ñuctuation spectrum on cluster scales is n \ [(1.72^0.34), where all errors are symmetrized at 68% conÐdence. The corresponding results for the case where a cosmological constant produces a Ñat universe are 0. 44^0.12, 0.77^0.15, and [ (1.68^0.38). These results agree with those determined from a variety of di †erent independent methods, including supernovae, galaxy-galaxy correlations, Ñuctuations in the microwave background, gravitational lens statistics, and cluster peculiar velocities.

Observational probes of cosmic acceleration

“…Existing cluster cosmology constraints have come primarily from X-ray data (see, e.g., Henry, 2000;Reiprich and Böhringer, 2002;Schuecker et al, 2003;Allen et al, 2003;Pierpaoli et al, 2003), reflecting the fact that X-ray observables can be related to mass via simulations and/or analytic approximations and by hydrostatic modeling for well observed clusters. All three of the most recent X-ray analyses yielded tight, consistent cosmological constraints, which can be summarized as σ 8 (Ω m /0.25) 0.45 = 0.80 ± 0.03 (Henry et al, 2009;Vikhlinin et al, 2009;.…”

Cosmological constraints from weak lensing peak statistics with Canada-France-Hawaii Telescope Stripe 82 Survey

“…where ρ(z) is the background matter density of the Universe at redshift z and the overdensity ∆ vir is taken from Henry (2000). The functionn c peak (ν, θ, M, z) in Eqn.…”

Constraints to cosmological parameters through cluster evolution

“…In this paper, we revisit the constraints obtained by several authors (Reichart et al 1999;Eke et al 1998;Henry 2000) Firstly, using the quoted improvements, we re-derive an expression for the X-ray Luminosity Function (XLF), similarly to Reichart et al (1999), and then we get some constraints to Ωm and n, by using the ROSAT BCS and EMSS samples and maximum-likelihood analysis. Then we re-derive the X-ray Temperature Function (XTF), similarly to Henry (2000), re-obtaining the constraints on Ωm, n, σ8.…”

“…Ω m ). In the following, we will recalculate the constraints obtained by Henry (2000), by using the mass function and the M-T relation modified as described in the previous section eq. (2.1) and eq.…”

“…At this point, we can fit the data described in Section. 2 of Henry (2000) to the theory previously described using the quoted maximum likelihood method. The most general description of the results requires the three parameters of the fit (Ω m , σ 8 and n).…”