Modelling The Redshift-Space Three-Point Correlation Function in SDSS-III

TL;DR

This paper measures the redshift-space three-point correlation function of luminous red galaxies at z~0.5, interprets it with halo models, and finds velocity bias effects are significant, offering insights into galaxy-halo relations.

Contribution

It provides the first detailed modeling of the redshift-space 3PCF for luminous red galaxies using halo occupation distribution and N-body simulations.

Findings

Model successfully reproduces 3PCF on scales >1 Mpc/h

Redshift-space 3PCF favors inclusion of galaxy velocity bias

Central galaxy exhibits motion relative to halo core

Abstract

We present the measurements of the redshift-space three-point correlation function (3PCF) for z~0.5 luminous red galaxies of the CMASS sample in the Sloan Digital Sky Survey-III Baryon Oscillation Spectroscopic Survey Data Release 11. The 3PCF measurements are interpreted within the halo occupation distribution framework using high-resolution N-body simulations, and the model successfully reproduces the 3PCF on scales larger than 1Mpc/h. As with the case for the redshift-space two-point correlation functions, we find that the redshift-space 3PCF measurements also favour the inclusion of galaxy velocity bias in the model. In particular, the central galaxy in a halo is on average in motion with respect to the core of the halo. We discuss the potential of the small-scale 3PCF to tighten the constraints on the relation between galaxies and dark matter haloes and on the phase-space distribution of galaxies.