CONSTRAINING THE COLD DARK MATTER SPECTRUM NORMALIZATION IN FLAT DARK ENERGY COSMOLOGIES

摘要

We study the relation between the rms mass fluctuations on 8 h~(-1) Mpc scales and Ω_m using the recent clustering results of XMM-Newton soft (0.5-2 keV) X-ray sources, which have a median redshift of z ～ 1.2. The relation can be represented in the form σ_8 = 0.34(±0.01)Ω_m~(-γ), where γ ≡ γ(Ω_m, w), and it is valid for all w < -(1/3) models. By combining the X-ray clustering and SN Ia data we find that the model that best reproduces the observational data is that with Ω_m approx= 0.26, w approx= —0.90, and σ_8 approx= 0.73, which is in excellent agreement with the recent 3 yr Wilkinson Microwave Anisotropy Probe results.