Constraints on cosmological parameters by the X-ray luminosity and temperature functions of galaxy clusters

Abstract

In this paper we revisit the constraints obtained by several authors on the estimated values of Ω m, the effective index of the mass density fluctuation spectrum on cluster scales, n, and σ 8 in the light of recent theoretical developments: (1) new theoretical mass functions; (2) a more accurate mass-temperature relation, also determined for arbitrary Ωm and ΩΛ. First, using the quoted improvements, we re-derive an expression for the X-ray Luminosity Function (XLF), and then we get some constraints to Ωmand n, by using the ROSAT BCS and EMSS samples and maximum-likelihood analysis. Then we re-derive the X-ray Temperature Function (XTF), re-obtaining the constraints on Ωm, n and σ 8. Both in the case of the XLF and XTF, the changes in the mass function and M-T relation produces an increase in Ωm of ≃ 20% and similar results in σ 8 and n.