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Title: Peculiar velocities in redshift space: formalism, N-body simulations and perturbation theory

Direct measurements of peculiar velocities of galaxies and clusters of galaxies can in principle provide explicit information on the three dimensional mass distribution, but this information is modulated by the fact that velocity field is sampled at galaxy positions, and is thus probing galaxy momentum. We derive expressions for the cross power spectrum between the density and momentum field and the auto spectrum of the momentum field in redshift space, by extending the distribution function method to these statistics. The resulting momentum cross and auto power spectra in redshift space are expressed as infinite sums over velocity moment correlators in real space, as is the case for the density power spectrum in redshift space. We compute each correlator using Eulerian perturbation theory (PT) and halo biasing model and compare the resulting redshift-space velocity statistics to those measured from N-body simulations for both dark matter and halos. We find that in redshift space linear theory predictions for the density-momentum cross power spectrum as well as for the momentum auto spectrum fail to predict the N-body results at very large scales. On the other hand, our nonlinear PT prediction for these velocity statistics, together with real-space power spectrum for dark matter frommore » simulations, improves the accuracy for both dark matter and halos. We also present the same analysis in configuration space, computing the redshift-space pairwise mean infall velocities and velocity correlation function and compare to nonlinear PT.« less
Authors:
;  [1] ;  [2] ;  [3]
  1. Institute for the Early Universe, Ewha Womans University, Seoul, 120-750 S. Korea (Korea, Republic of)
  2. Physik Institut, University of Zurich, Zurich, 8057 (Switzerland)
  3. Département de Physique Théorique and Center for Astroparticle Physics (CAP), Université de Genève, Genève, 1211 (Switzerland)
Publication Date:
OSTI Identifier:
22373611
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2014; Journal Issue: 05; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CORRELATION FUNCTIONS; DISTRIBUTION FUNCTIONS; GALAXIES; GALAXY CLUSTERS; MASS DISTRIBUTION; NONLINEAR PROBLEMS; NONLUMINOUS MATTER; PERTURBATION THEORY; RED SHIFT; SIMULATION; SPACE; SPECTRA; VELOCITY