Tests of gravity with DES Year 3 weak lensing

The new weak lensing measurements from the first three years of observation by the Dark Energy Survey offer a unique opportunity to constrain deviations from General Relativity, our theory of gravity. Weak gravitational lensing is indeed a powerful probe of the growth of structures. As such it offers a window on the laws of gravity on cosmological scales. We thus used DES Year 3 weak lensing data to test the validity of General Relativity (GR) to a new regime, and explore modifications to GR as an alternative to dark energy. I will present the results of our analysis, the modeling choices and robust approach we adopted to reliably test gravity with these precise data. I will end by highlighting ongoing work in DES and the main challenges to solve in future galaxy surveys like LSST, Euclid and Roman.