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We calculate the non-linear galaxy power spectrum in real space, including non-linear distortion of the Baryon Acoustic Oscillations, using the standard 3rd-order perturbation theory (PT). The calculation is based upon the assumption that the number density of galaxies is a local function of the underlying, non-linear density field. The galaxy bias is allowed to be both non-linear and stochastic. We show that the PT calculation agrees with the galaxy power spectrum estimated from the Millennium Simulation, in the weakly non-linear regime (defined by the matter power spectrum) at high redshifts, $1le zle6$. We also show that, once 3 free parameters characterizing galaxy bias are marginalized over, the PT power spectrum fit to the Millennium Simulation data yields unbiased estimates of the distance scale, $D$, to within the statistical error. This distance scale corresponds to the angular diameter distance, $D_A(z)$, and the expansion rate, $H(z)$, in real galaxy surveys. Our results presented in this paper are still restricted to real space. The future work should include the effects of non-linear redshift space distortion. Nevertheless, our results indicate that non-linear galaxy bias in the weakly non-linear regime at high redshifts is reasonably under control.
An acoustic oscillation of the primeval photon-baryon fluid around the decoupling time imprints a characteristic scale in the galaxy distribution today, known as the baryon acoustic oscillation (BAO) scale. Several on-going and/or future galaxy surve
Baryon Acoustic Oscillations (BAO) are frozen relics left over from the pre-decoupling universe. They are the standard rulers of choice for 21st century cosmology, providing distance estimates that are, for the first time, firmly rooted in well-under
Integral equations for meson-baryon scattering amplitudes are obtained by utilizing time-ordered perturbation theory for a manifestly Lorentz-invariant formulation of baryon chiral perturbation theory. Effective potentials are defined as sums of two-
We report on the recent studies of leading order baryon-baryon interactions in covariant baryon chiral perturbation theory. In the strangeness $S=0$ sector, one can achieve a rather good description of the Nijmegen $np$ phase shifts with angular mome
We study the nonlinear evolution of the baryon acoustic oscillations (BAO) in the dark matter power spectrum and correlation function using renormalized perturbation theory (RPT). In a previous paper we showed that RPT successfully predicts the dampi