Nonlinear Biasing and Redshift-Space Distortions in Lagrangian Resummation Theory and N-body Simulations

TL;DR

This paper demonstrates that Lagrangian resummation theory accurately models nonlinear halo biasing and redshift-space distortions, matching N-body simulations and aiding precise BAO measurements in future galaxy surveys.

Contribution

It validates the effectiveness of Lagrangian resummation theory in modeling nonlinear bias and redshift-space distortions across various redshifts, improving cosmological analysis accuracy.

Findings

LRT matches N-body simulations within a few percent on BAO scales.

Nonlinear effects on BAO peaks are well explained by LRT.

LRT accurately reproduces bias scale dependence up to specified k-values.

Abstract

Understanding a behavior of galaxy biasing is crucial for future galaxy redshift surveys. One aim is to measure the baryon acoustic oscillations (BAOs) within the precision of a few percent level. Using 30 large cosmological N-body simulations for a standard LCDM cosmology, we study the halo biasing over a wide redshift range. We compare the simulation results with theoretical predictions proposed by Matsubara (2008) which naturally incorporate the halo bias and redshift-space distortions into their formalism of perturbation theory with a resummation technique via the Lagrangian picture. The power spectrum and correlation function of halos obtained from Lagrangian resummation theory (LRT) well agree with N-body simulation results on scales of BAOs. Especially nonlinear effects on the baryon acoustic peak of the halo correlation function are accurately explained both in real and redshift space. We find that nonlinearity and scale dependence of bias are fairly well reproduced by 1-loop LRT up to k=0.35hMpc^{-1} (z=2 and 3) within a few percent level in real space and up to k=0.1hMpc^{-1} (z=2) and 0.15hMpc^{-1} (z=3) in redshift space. Thus, the LRT is very powerful for accurately extracting cosmological information in upcoming high redshift BAO surveys.