Cosmological dependence of the measurements of luminosity function, projected clustering and galaxy-galaxy lensing signal

TL;DR

This paper investigates how cosmological assumptions influence galaxy measurements like luminosity function, clustering, and lensing, highlighting potential biases in cosmological parameter estimation from these observables.

Contribution

It quantifies the systematic variations caused by different fiducial cosmologies and provides a simple mapping method to correct measurements across models.

Findings

Systematic effects are significant at high redshift (~0.5).

A simple mapping method allows translating measurements between cosmologies.

Ignoring these effects can underestimate uncertainties in cosmological constraints.

Abstract

Observables such as the luminosity function of galaxies, \Phi(M), the projected clustering of galaxies, w_p(r_p), and the galaxy-galaxy lensing signal, \Delta\Sigma, are often measured from galaxy redshift surveys assuming a fiducial cosmological model for calculating distances to and between galaxies. There is a growing number of studies that perform joint analyses of these measurements and constrain cosmological parameters. We quantify the amount by which such measurements systematically vary as the fiducial cosmology used for the measurements is changed, and show that these effects can be significant at high redshifts (z~0.5). We present a simple way that maps the measurements made using a particular fiducial cosmological model to any other cosmological model. Cosmological constraints (or halo occupation distribution constraints) that use the luminosity function, clustering measurements and galaxy-galaxy lensing signal but ignore these systematic effects may underestimate the confidence intervals on the inferred parameters.