Cosmic Data Fusion

We compare and combine likelihood functions of the cosmological parameters Ω m , h and σ 8 from the CMB, type Ia supernovae and from probes of large scale structure. We include the recent results from the CMB experiments BOOMERANG and MAXIMA-1. Our analysis assumes a flat ACDM cosmology with a scale-invariant adiabatic initial power spectrum. First we consider three data sets that directly probe the mass in the Universe, without the need to relate the galaxy distribution to the underlying mass via a “biasing” relation: peculiar velocities, CMB and supernovae. We assume a baryonic fraction as inferred from Big-Bang Nucleosynthesis and find that all three data sets agree well, overlapping significantly at the 2σ level. This therefore justifies a joint analysis, in which we find a joint best fit point and 95% confidence limits of Ω m = 0.28 (0.17, 0.39), h = 0.74 (0.64, 0.86), and σ 8 = 1.17 (0.98,1.37). Secondly we extend our earlier work on combining CMB, supernovae, cluster number counts, IRAS galaxy redshift survey data to include BOOMERANG and MAXIMA-1 data and to allow a free Ω b h 2 . We find that, given our assumption of a scale invariant initial power spectrum ( n = 1), we obtain the robust result of Ω b h 2 = 0.031 ± 0.03, which is dominated by the CMB constraint.