Constraining Modified Gravity with Euclid

TL;DR

This paper forecasts Euclid's potential to significantly tighten constraints on modified gravity theories like scalar-tensor and $f(R)$ models using galaxy weak lensing data, surpassing current limits.

Contribution

It provides a forecast of Euclid's ability to constrain modified gravity models, highlighting improvements over previous constraints and discussing potential biases.

Findings

Euclid will improve constraints on modified gravity by two orders of magnitude.

Parameter degeneracies and biases in modified gravity models are analyzed.

Euclid's measurements can test deviations from general relativity on cosmic scales.

Abstract

Future proposed satellite missions as Euclid can offer the opportunity to test general relativity on cosmic scales through mapping of the galaxy weak lensing signal. In this paper we forecast the ability of these experiments to constrain modified gravity scenarios as those predicted by scalar-tensor and $f(R)$ theories. We found that Euclid will improve constraints expected from the PLANCK satellite on these modified gravity models by two orders of magnitude. We discuss parameter degeneracies and the possible biases introduced by modified gravity.