Speaker
Description
The Dark Energy Survey Year 6 (DES Y6) represents the final and most statistically powerful dataset from DES, enabling sub-percent level cosmological constraints from weak lensing and galaxy clustering. We present the methodology underpinning the cosmic shear, 2×2pt, and 3×2pt analyses, focusing on the novel design choices that make this pipeline both robust and forward-looking. Key methodological contributions include a principled scale-cut framework that jointly accounts for baryonic feedback and non-linear galaxy bias uncertainties, and a validation strategy based on mock data and simulations that explicitly addresses posterior projection effects, critical for unbiased inference in high-dimensional parameter spaces. We also present the theoretical covariance matrix framework and systematic mitigation prescription adopted for both ΛCDM and wCDM analyses. Beyond DES Y6, this framework is designed with direct applicability to next-generation surveys such as Rubin/LSST, making it a reference methodology for the coming era of stage-IV weak lensing cosmology.