Measuring Omega_m using clusters evolution

Abstract

The constraints obtained by several authors (Eke et al. 1998; Henry 2000) on the estimated values of $Ω_{\rm m}$, $n$ and $σ_8$ are revisited in the light of recent theoretical developments: 1) new theoretical mass functions; 2) a more accurate mass-temperature relation, also determined for arbitrary $Ω_{\rm m}$ and $Ω_{\rm Λ}$. I re-derive the X-ray Temperature Function (XTF), similarly to Henry (2000) and Eke et al. (1999), re-obtaining the constraints on $Ω_{\rm m}$, $n$, $σ_8$. The result shows that 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 $n$.