Study on the mapping of halo clustering from real space to redshift space

TL;DR

This paper investigates the complex mapping of galaxy clustering from real to redshift space, accounting for non-linear effects, halo bias, and Finger-of-God phenomena, and validates a model with simulation data.

Contribution

It extends the TNS redshift space distortion model to halos, incorporating halo bias and FoG effects, and demonstrates high accuracy with N-body simulations.

Findings

The halo RSD model predicts the halo power spectrum within 1-2% accuracy.

The model remains accurate up to k~0.2h/Mpc across various halo masses and redshifts.

Validation with 100 simulation realizations confirms the model's robustness.

Abstract

The mapping of galaxy clustering from real space to redshift space introduces the anisotropic property to the measured galaxy density power spectrum in redshift space, known as the redshift space distortion (RSD) effect. The mapping formula is intrinsically non-linear, which is complicated by the higher order polynomials due to indefinite orders of cross correlations between density and velocity fields, and the Finger--of--God (FoG) effect due to the randomness of the galaxy peculiar velocity field. In previous works, we have verified the robustness of advanced TNS mapping formula in our hybrid RSD model in dark matter case, where the halo bias models are not taken into account for the halo mapping formula in redshift space. Using 100 realizations of halo catalogs in N-body simulations, we find that our halo RSD model with the known halo bias model and the effective FoG function accurately predicts the halo power spectrum measurements, within 1$\sim$2% accuracy up to $k\sim 0.2h$/Mpc, depending on different halo masses and redshifts.