Estimator for the anisotropic stress using relativistic effects in Large-Scale Structure

TL;DR

This paper proposes a new method to measure the anisotropic stress in the universe by utilizing relativistic effects, especially gravitational redshift, in large-scale structure observations, providing a model-independent test of General Relativity.

Contribution

It introduces an estimator based on relativistic effects, particularly gravitational redshift, to directly measure anisotropic stress in a model-independent manner.

Findings

Demonstrates how relativistic effects influence galaxy distributions

Develops an estimator for anisotropic stress using gravitational redshift

Provides a framework for testing General Relativity on cosmological scales

Abstract

The large-scale structure of the Universe is a rich source of information to test the consistency of General Relativity on cosmological scales. We briefly describe how the observed distributions of galaxies is affected by redshift-space distortions, but also by gravitational lensing and other relativistic effects. Then, we show how one of this relativistic effects, the gravitational redshift, can be used to build a model independent test that directly measures the anisotropic stress, i.e. the difference between the two gravitational potentials that describe spacetime fluctuations of the geometry.