Testing General Relativity through the $E_G$ Statistic Using the Weyl Potential and Galaxy Velocities

We combine measurements of galaxy velocities from galaxy surveys with measurements of the Weyl potential from the Dark Energy Survey to test the consistency of General Relativity at cosmological scales. Taking the ratio of two model-independent observables - the growth rate of structure and the Weyl potential - we obtain new measurements of the $E_G$ statistic with precision of $6.0-11.3\%$ at four different redshifts. These measurements provide a considerable improvement to past measurements of $E_G$. They confirm the validity of General Relativity at four redshifts, with a deviation of at most $1.6\sigma$ from the predicted values. Contrary to conventional methods that rely on a common galaxy sample with spectroscopic resolution to measure two types of correlations, we directly combine two observables that are independent of the galaxy bias. This provides a novel approach to testing the relation between the geometry of our Universe and the motion of galaxies with improved precision.