1999/04/09 by Wolfram Freudling, Idit Zehavi, Luiz N. da Costa +7 · 4 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.1086/307707
published as Astrophys.J. 523 (1999) 1 · 35 pages, 11 figures. To appear in the Astrophysical Journal
arxiv created 1999/04/09 · openalex publication_date 1999/09/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
We estimate the power spectrum of mass density fluctuations from peculiar velocities of galaxies by applying an improved maximum likelihood technique to the new all-sky SFI catalog. Parametric models are used for the power spectrum and the errors, and the free parameters are determined by assuming Gaussian velocity fields and errors and maximizing the probability of the data given the model. It has been applied to generalized cold dark matter (CDM) models with and without COBE normalization. The method has been carefully tested using artificial SFI catalogs. The most likely distance errors are found to be similar to the original error estimates in the SFI data. The general result that is not very sensitive to the prior model used is a relatively high amplitude of the power spectrum. For example, at k = 0.1 h Mpc -1 we find P ( k )Ω 1.2 = (4.4 ± 1.7) × 10 3 ( h -1 Mpc) 3 . An integral over the power spectrum yields σ 8 Ω 0.6 = 0.82 ± 0.12. Model-dependent constraints on the cosmological parameters are obtained for families of CDM models. For example, for COBE -normalized ΛCDM models (scalar fluctuations only), the maximum likelihood result can be approximated by Ω n 2 h 1.3 60 = 0.58 ± 0.11. The formal random errors quoted correspond to the 90% confidence level. The total uncertainty, including systematic errors associated with nonlinear effects, may be larger by a factor of ~2. These results are in agreement with an application of a similar method to other data (Mark III).