1998/04/06 by R. Valdarnini, Valdarnini, R., T. Kahniashvili +4
Physics and Astronomy · #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9804057
19 pages, 21 figures, accepted by A&A
arxiv created 1998/04/06 · arxiv updated 2009/12/01
We study linear power spectra and formation of large scale structures in flat cosmological models with Λ≥ 0 and cold plus hot dark matter components (MLM). The hot component consists of massive neutrinos with cosmological density ΩH. The linearized Einstein-Boltzmann equations for the evolution of the metric and density perturbations are integrated for a set of values of the cosmological parameters. For all the considered models we assume a scale-invariant primeval spectrum. The density weighted final linear power spectra are normalized to the four year COBE data and have been used to constrain the parameter space by a comparison of linear predictions with the current observational data on large scales. The consistency of MLM predictions with the observable data set is best obtained for models with one specie of massive neutrinos and ΩH/ΩM ≤0.2. For this class of MLM models we obtain constraints from linear data on the present matter density. Consistency with the estimated cluster abundance can be achieved for COBE normalized MLM models with ΩH/ΩM≤0.2 and 0.45 ≤ ΩM ≤ 0.75 for h=0.5. If h=0.7 then 0.3 ≤ ΩM ≤ 0.5. These constraints are at 1σ level and standard MDM models are clearly ruled out. We note that the range of allowed values for ΩM, that we obtain for MLM models from linear analysis, is also approximately the same range that is needed in order to consistently satisfy a variety of independent observational constraints.