An analytic halo approach to the bispectrum of galaxies in redshift space

TL;DR

This paper develops an analytic model for the galaxy bispectrum in redshift space using the halo approach, highlighting the impact of satellite galaxies and Fingers of God effects on higher multipoles, validated against simulations.

Contribution

It extends previous power spectrum models to the bispectrum, providing analytic formulas and emphasizing the role of satellite galaxies and redshift space distortions.

Findings

Fingers of God significantly affect higher multipoles of the bispectrum.

Analytic formulas match simulation results for the LOWZ sample.

Satellite galaxies contribute notably to non-linear redshift space distortions.

Abstract

We present an analytic formula for the galaxy bispectrum in redshift space on the basis of the halo approach description with the halo occupation distribution of central galaxies and satellite galaxies. This work is an extension of a previous work on the galaxy power spectrum, which illuminated the significant contribution of satellite galaxies to the higher multipole spectrum through the non-linear redshift space distortions of their random motions. Behaviors of the multipoles of the bispectrum are compared with results of numerical simulations assuming a halo occupation distribution of the LOWZ sample of the SDSS-III BOSS survey. Also presented are analytic approximate formulas for the multipoles of the bispectrum, which is useful to understanding their characteristic properties. We demonstrate that the Fingers of God effect is quite important for the higher multipoles of the bispectrum in redshift space, depending on the halo occupation distribution parameters.