Scaling properties of the redshift power spectrum: theoretical models

Sep, 2000
24 pages
Published in:
  • Astrophys.J. 547 (2001) 545
e-Print:

Citations per year

20012007201320192023104
Abstract: (arXiv)
We report the results of an analysis of the redshift power spectrum PS(k,μ)P^S(k,\mu) in three typical Cold Dark Matter (CDM) cosmological models, where μ\mu is the cosine of the angle between the wave vector and the line-of-sight. Two distinct biased tracers derived from the primordial density peaks of Bardeen et al. and the cluster-underweight model of Jing, Mo, & B\orner are considered in addition to the pure dark matter models. Based on a large set of high resolution simulations, we have measured the redshift power spectrum for the three tracers from the linear to the nonlinear regime. We investigate the validity of the relation - guessed from linear theory - in the nonlinear regime PS(k,μ)=PR(k)[1+βμ2]2D(k,μ,σ12(k)), P^S(k,\mu)=P^R(k)[1+\beta\mu^2]^2D(k,\mu,\sigma_{12}(k)), where PR(k)P^R(k) is the real space power spectrum, and β\beta equals Ω00.6/bl\Omega_0^{0.6}/b_l. The damping function DD which should generally depend on kk, μ\mu, and σ12(k)\sigma_{12}(k), is found to be a function of only one variable kμσ12(k)k\mu\sigma_{12}(k). This scaling behavior extends into the nonlinear regime, while DD can be accurately expressed as a Lorentz function - well known from linear theory - for values D>0.1D > 0.1. The difference between σ12(k)\sigma_{12}(k) and the pairwise velocity dispersion defined by the 3-D peculiar velocity of the simulations (taking r=1/kr=1/k) is about 15%. Therefore σ12(k)\sigma_{12}(k) is a good indicator of the pairwise velocity dispersion. The exact functional form of DD depends on the cosmological model and on the bias scheme. We have given an accurate fitting formula for the functional form of DD for the models studied.