The nonlinear redshiftspace power spectrum of galaxies
Abstract
We study the power spectrum of galaxies in redshift space, with thirdorder perturbation theory to include corrections that are absent in linear theory. We assume a local bias for the galaxies: i.e., the galaxy density is sampled from some local function of the underlying mass distribution. We find that the effect of the nonlinear bias in real space is to introduce two new features: first, there is a contribution to the power which is constant with wavenumber, whose nature we reveal as essentially a shotnoise term. In principle this contribution can mask the primordial power spectrum, and could limit the accuracy with which the latter might be measured on very large scales. Secondly, the effect of second and thirdorder bias is to modify the effective bias (defined as the square root of the ratio of galaxy power spectrum to matter power spectrum). The effective bias is almost scaleindependent over a wide range of scales. These general conclusions also hold in redshift space. In addition, we have investigated the distortion of the power spectrum by peculiar velocities, which may be used to constrain the density of the Universe. We look at the quadrupoletomonopole ratio, and find that higher order terms can mimic linear theory bias, but the bias implied is neither the linear bias, nor the effective bias referred to above. We test the theory with biased Nbody simulations, and find excellent agreement in both real and redshift space, providing the local biasing is applied on a scale whose fractional rms density fluctuations are <0.5.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 December 1998
 DOI:
 10.1046/j.13658711.1998.02052.x
 arXiv:
 arXiv:astroph/9808016
 Bibcode:
 1998MNRAS.301..797H
 Keywords:

 GALAXIES: CLUSTERS: GENERAL;
 COSMOLOGY: THEORY;
 LARGESCALE STRUCTURE OF UNIVERSE;
 Astrophysics
 EPrint:
 13 pages, 7 figures. Accepted by MNRAS