TH Cosmo Coffee

Modelling the redshift-space distortions in the galaxy clustering

by Zvonimir Vlah (Institute for Theoretical Physics, University of Zurich)

Wednesday, 22 January 2014 from to (Europe/Zurich)
at CERN ( 4-2-011 - TH common room )
Description
In galaxy clustering surveys redshift corresponds to the true distance according to the Hubble Law. In addition peculiar velocities induced by the local gravitational potential are not associated with the Hubble flow and can cause distortions in redshift space. We study these distortions in phase space distribution function approach in order to model the power spectra of dark matter and halos. In this approach RSD of dark matter halos can be written as a sum over density weighted velocity moments correlators, with the lowest order being density, momentum density and stress energy density. Modelling of these contributing terms is done by combining perturbative methods and non-local biasing model to connect halos to the underlying dark matter distribution. In modelling the isotropic part of the RSD power spectrum we go beyond the Poissonian estimates of shot noise and allow for the scale dependence seen in the N-body simulation data. We present the results of RSD model for multipoles as well as dependence of the power spectrum on the amplitude and direction of the Fourier modes. Transforming these we also obtain the results in configuration space. In addition to the power spectra we also show the models for the velocity statistics in the resdhift space.