Abstract

I will present status of the cosmological combined weak lensing and clustering analysis from the Dark Energy Survey (DES) using its first three years of data taken at the 4m Blanco telescope at CTIO . This analysis spans the full DES footprint, more than 4000 sq. deg. of sky, with the final shear catalogue containing more than 100 million galaxies in riz photometric bands, constituting the most powerful weak lensing dataset to date. The comparison of DES cosmological constraints on dark matter and dark energy from WL and LSS in the low-redshift Universe to CMB constraints provides an unprecedented test of the standard cosmological model, across high and low redshift. I will summarise the main challenges that weak lensing analyses are susceptible to, such as shear calibration and redshift estimation, as well as the DES -Year 3 approach to account for these and deliver robust cosmological constraints.