Breaking the ACDM degeneracy using CMB data

Abstract

Recent measurements of the cosmic microwave background radiation (CMB) from the WMAP satellite led to formulate a successful concordance cosmological model, termed ACDM. This model satisfactorily explains the origin and structure of the CMB temperature fluctuations, from small to large angular scales, and moreover it accurately fits -with only six parameters- the CMB angular power spectrum. Despite of their triumphs in describing the observed WMAP data, we notice that some ACDM cosmological parameters can attain, due to their error bars, slightly different values and this degree of freedom could produce a significant impact in our understanding of the primordial universe. We are talking about the degeneracy problem, that is cosmological models with parameters that are a little bit different from those given by the ACDM model but fits equally well the angular power spectrum of the CMB data. Our interest here is to investigate the Gaussian statistical property, at large angular scales, in two sets of Monte Carlo CMB maps produced by seeding them with slightly different ACDM angular power spectra.