Combining Supernovae and LSS Information with the CMB

Original · EN

Observations of the Cosmic Microwave Background (CMB), large scale structure (LSS) and standard candles such as Type 1a Supernovae (SN) each place different constraints on the values of cosmological parameters. We assume an inflationary Cold Dark Matter model with a cosmological constant, in which the initial density perturbations in the universe are adiabatic. We discuss the parameter degeneracies inherent in interpreting CMB or SN data, and derive their orthogonal nature. We then present our preliminary results of combining CMB and SN likelihood functions. The results of combining the CMB and IRAS 1.2 Jy survey information are given, with marginalised confidence regions in the H₀, Omegaₘ, bᵢRAS and Qᵣms-ps directions assuming n=1, Omegaₗambda+Omegaₘ=1 and Omegab h²=0.024. Finally we combine all three likelihood functions and find that the three data sets are consistent and suitably orthogonal, leading to tight constraints on H₀, Omegaₘ, bᵢRAS and Qᵣms-ps, given our assumptions.