Lensing convergence in galaxy clustering in LambdaCDM and beyond

TL;DR

Neglecting lensing magnification in galaxy clustering analyses can bias parameter estimates, especially for modified gravity models, highlighting the importance of including lensing effects in future surveys like Euclid and SKA.

Contribution

This study quantifies the biases caused by ignoring lensing magnification in galaxy clustering for LambdaCDM and its extensions, providing fitting formulas and emphasizing the need for lensing inclusion.

Findings

Lensing improves constraints on modified gravity parameters.

Neglecting lensing biases parameter estimates in photometric surveys.

Spectroscopic surveys are less affected by lensing neglect.

Abstract

We study the impact of neglecting lensing magnification in galaxy clustering analyses for future galaxy surveys, considering the LambdaCDM model and two extensions: massive neutrinos and modifications of General Relativity. Our study focuses on the biases on the constraints and on the estimation of the cosmological parameters. We perform a comprehensive investigation of these two effects for the upcoming photometric and spectroscopic galaxy surveys Euclid and SKA for different redshift binning configurations. We also provide a fitting formula for the magnification bias of SKA. Our results show that the information present in the lensing contribution does improve the constraints on the modified gravity parameters whereas the lensing constraining power is negligible for the LambdaCDM parameters. For photometric surveys the estimation is biased for all the parameters if lensing is not taken into account. This effect is particularly significant for the modified gravity parameters. Conversely for spectroscopic surveys the bias is below one sigma for all the parameters. Our findings show the importance of including lensing in galaxy clustering analyses for testing General Relativity and to constrain the parameters which describe its modifications.