Testing gravity on cosmological scales with cosmic shear, cosmic microwave background anisotropies, and redshift-space distortions

TL;DR

This study combines multiple cosmological observations to test for deviations from general relativity on large scales, finding no significant evidence for modifications and forecasting improved future constraints.

Contribution

It provides the first comprehensive constraints on phenomenological modifications to gravity using diverse cosmological data sets and forecasts future survey sensitivities.

Findings

No evidence of deviations from general relativity.

Constraints on modified gravity parameters are tight, with $\Sigma_0$ and $\mu_0$ close to zero.

Future surveys will significantly improve these constraints.

Abstract

We use a range of cosmological data to constrain phenomenological modifications to general relativity on cosmological scales, through modifications to the Poisson and lensing equations. We include cosmic microwave background anisotropy measurements from the Planck satellite, cosmic shear from CFHTLenS and DES-SV, and redshift-space distortions from BOSS data release 12 and the 6dF galaxy survey. We find no evidence of departures from general relativity, with the modified gravity parameters constrained to $\Sigma_0 = 0.05^{+0.05}_{-0.07}$ and $\mu_0 = -0.10^{+0.20}_{-0.16}$, where $\Sigma_0$ and $\mu_0$ refer to deviations from general relativity today and are defined to be zero in general relativity. We also forecast the sensitivity to those parameters of the full five-year Dark Energy Survey and of an experiment like the Large Synoptic Survey Telescope, showing a substantial expected improvement in the constraint on $\Sigma_0$.