Weak Lensing Effects on the Galaxy Three-Point Correlation Function

TL;DR

This paper investigates how weak lensing magnification affects the galaxy three-point correlation function, deriving correction terms and showing their significance depends on geometry, galaxy sample, and redshift.

Contribution

It provides the first comprehensive derivation of second-order weak lensing corrections to the galaxy 3PCF with analytic expressions and numerical estimates.

Findings

Weak lensing can significantly alter the observed 3PCF.

Corrections depend on triangle configuration and galaxy sample.

Magnification effects vary with redshift and number count slope.

Abstract

We study the corrections to the galaxy three-point correlation function (3PCF) induced by weak lensing magnification due to the matter distribution along the line of sight. We consistently derive all the correction terms arising up to second order in perturbation theory and provide analytic expressions as well as order of magnitude estimates for their relative importance. The magnification contributions depend on the geometry of the projected triangle on the sky plane, and scale with different powers of the number count slope and redshift of the galaxy sample considered. We evaluate all terms numerically and show that, depending on the triangle configuration as well as the galaxy sample considered, weak lensing can in general significantly contribute to and alter the three-point correlation function observed through galaxy and quasar catalogs.