Large-scale bias in the Universe — II. Redshift-space bispectrum |
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Authors: | L Verde A F Heavens S Matarrese & L Moscardini |
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Institution: | Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ,;Dipartimento di Fisica;Galileo Galilei, Universitàdi Padova, via Marzolo 8, I-35131 Padova, Italy, Dipartimento di Astronomia, Universitàdi Padova, vicolo dell'Osservatorio 5, I-35122 Padova, Italy |
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Abstract: | The determination of the density parameter Ω0 from the large-scale distribution of galaxies is one of the major goals of modern cosmology. However, if galaxies are biased tracers of the underlying mass distribution, linear perturbation theory leads to a degeneracy between Ω0 and the linear bias parameter b , and the density parameter cannot be estimated. In Matarrese, Verde &38; Heavens we developed a method based on second-order perturbation theory to use the bispectrum to lift this degeneracy by measuring the bias parameter in an Ω0-independent way. The formalism was developed assuming that one has perfect information on the positions of galaxies in three dimensions. In galaxy redshift surveys, the three-dimensional information is imperfect, because of the contaminating effects of peculiar velocities, and the resulting clustering pattern in redshift space is distorted. In this paper we combine second-order perturbation theory with a model for collapsed, virialized structures, to extend the method to redshift space, and demonstrate that the method should be successful in determining with reasonable accuracy the bias parameter from state-of-the-art surveys such as the Anglo-Australian 2 degree Field Survey and the Sloan Digital Sky Survey. |
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Keywords: | galaxies: clusters: general cosmology: theory large-scale structure of Universe |
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