Dark Energy Survey Year 6 results : Galaxy-galaxy lensing

UNSPECIFIED (2026) Dark Energy Survey Year 6 results : Galaxy-galaxy lensing. Physical Review D, 113 (10): 103503. ISSN 2470-0010

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Abstract

We present galaxy-galaxy lensing measurements from the full six years of data from the Dark Energy Survey (DES Y6), covering 4031  deg2 and used in the DES Y6 3×2  pt cosmological analysis. We use the Maglim++ lens sample, containing ∼9  million galaxies divided into six redshift bins, and the Metadetection source catalog, including ∼140  million galaxies divided into four redshift bins. The mean tangential shear signal achieves a total signal-to-noise ratio (S/N) of 173, corresponding to a 17% improvement over DES Y3. After applying the scale cuts used in the cosmological analysis, with min =6  Mpc/ℎ (4  Mpc/ℎ) for the linear (nonlinear) galaxy-bias model, the S/N is reduced to 75 (90). A comprehensive suite of validation tests demonstrates that the measurement is robust against observational and astrophysical systematics at the statistical precision required for the DES Y6 analysis. Although not used in the main cosmological analysis, we extract high signal-to-noise geometric shear-ratio measurements from the galaxy-galaxy lensing signal on small angular scales. These measurements provide an internal consistency check on the photometric redshift distributions and shear calibration used in the 3 ×2  pt analysis.