We use a generalised procedure for the combined likelihood analysis of different cosmological probes , the ‘ Hyper-Parameters ’ method , that allows freedom in the relative weights of the raw measurements .
We perform a joint analysis of the cepheid-calibrated data from the Hubble Space Telescope Key Project and the baryon mass fraction in clusters to constrain the total matter density of the universe , \Omega _ { m } , and the Hubble parameter , h .
We compare the results obtained using Hyper-Parameters method with the estimates from standard \chi ^ { 2 } analysis .
We assume that the universe is spatially flat , with a cosmological constant .
We adopt the Big-Bang nucleosynthesis constraint for the baryon density , assuming the uncertainty is Gaussian distributed .
Using this and the cluster baryon fraction data , we find that the matter density and the Hubble constant are correlated , \Omega _ { m } h ^ { 0.5 } \approx 0.25 , with preference for a very high h .
To break the degeneracy , we add in the cepheid-calibrated data and find the best fit values ( \Omega _ { m } , h ) = ( 0.26 ^ { +0.06 } _ { -0.06 } , 0.72 ^ { +0.04 } _ { -0.02 } ) ( 68 per cent confindence limits ) using the Hyper-Parameters approach .
We use the derived Hyper-Parameters to ‘ grade ’ the 6 different data sets we analyse .
Although our analysis is free of assumptions about the power spectrum of fluctuations , our results are in agreement with the \Lambda -Cold Dark Matter ‘ concordance ’ parameters derived from the Cosmic Microwave Background anisotropies combined with Supernovae Ia , redshift surveys and other probes .