S. Basilakos, M. Plionis
Monthly Notices of the Royal Astronomical Society: Letters, Volume 360, Issue 1, June 2005, Pages L35–L38
Publication year: 2005

Summary 

We put constraints on the main cosmological parameters of different spatially flat cosmological models by combining the recent clustering results of XMM–Newton soft (0.5–2 keV) X-ray sources, which have a redshift distribution with median redshift z ∼ 1.2, and Type Ia supernova data. Using a likelihood procedure we find that the model that best reproduces the observational data and which is consistent with stellar ages is the concordance λ cold dark matter model with Ω m ≃ 0.28, w ≃ −1, H0 ≃ 72 km s-1 Mpc−1 and t0 ≃ 13.5 Gyr, and has an X-ray active galactic nucleus clustering evolution which is constant in physical coordinates. For a different clustering evolution model (constant in comoving coordinates) we find another viable model, although less probable because of the smaller age of the universe, with Ωm ≃ 0.38, w ≃−1.25, H0 ≃ 70 km s−1 Mpc−1 and t0 ≃ 12.9 Gyr.