Constraints on cosmological parameters through clusters XLF and XTF

Abstract

In this paper, I revisit the constraints obtained by several authors (Reichart et al. 1999; Eke et al. 1998; Henry 2000) on the estimated values of $Ω_{\rm m}$, $n$ and $σ_8$ in the light of recent theoretical developments: 1) new theoretical mass functions (Sheth & Tormen 1999, Sheth, Mo & Tormen 2001, Del Popolo 2002b); 2) a more accurate mass-temperature relation, also determined for arbitrary $Ω_{\rm m}$ and $Ω_{\rm Λ}$ (Del Popolo 2002a). Firstly, using the quoted improvements, I re-derive an expression for the X-ray Luminosity Function (XLF), similarly to Reichart et al. (1999), and then I get some constraints to $Ω_{\rm m}$ and $n$, by using the {\it ROSAT} BCS and {\rm EMSS} samples and maximum-likelihood analysis. Then I re-derive the X-ray Temperature Function (XTF), similarly to Henry (2000), re-obtaining the constraints on $Ω_{\rm m}$, $n$, $σ_8$. Both in the case of the XLF and XTF, the changes in the mass function and M-T relation produces an increase in $Ω_{\rm m}$ of $ \simeq 20%$ and similar results in $σ_8$ and $n$.