Constraining our Universe with X-ray and optical cluster data

We have used recent X-ray and optical data in order to impose some constrai nts on the cosmology and cluster scaling relations. Generically, two kinds of hypotheses define our model. First, we consider t hat the cluster population is well described by the standard Press-Schechte r (PS) formalism, and secondly, these clusters are assumed to follow scalin g relations with mass: temperature-mass (T-M) and X-ray luminosity -mass (L -x-M). In contrast with many other authors we do not assume specific scaling relat ions to model cluster properties such as the usual T-M virial relation or a n observational relation or an observational determination of the L-x-T rel ation. Instead we consider general unconstrained parameter scaling relation s. With the previous model (PS plus scalings) we fit our free parameters to se veral X-ray and optical data sets with the advantage over preceding works t hat we consider all the data sets at the same time. This prevents us from b eing inconsistent with some of the available observations. Among other inte resting conclusions, we find that only low-density universes are compatible with all the data considered and that the degeneracy between Omega (m) and sigma (8) is broken. Also we obtain interesting limits on the parameters c haracterizing the scaling relations.