Dark Energy Survey Year 6 Results : Cell-based Coadds and Metadetection Weak Lensing Shape Catalogue

Yamamoto, M and Becker, M R and Sheldon, E and Jarvis, M and Gruendl, R A and Menanteau, F and Rykoff, E S and Mau, S and Schutt, T and Gatti, M and Troxel, M A and Amon, A and Anbajagane, D and Bernstein, G M and Gruen, D and Huff, E M and Tabbutt, M and Tong, A and Yanny, B and Abbott, T M C and Aguena, M and Alarcon, A and Andrade-Oliveira, F and Bechtol, K and Blazek, J and Brooks, D and Rosell, A Carnero and Carretero, J and Chang, C and Choi, A and Costanzi, M and Crocce, M and da Costa, L N and Davis, T M and De Vicente, J and Desai, S and Diehl, H T and Dodelson, S and Doel, P and Doux, C and Drlica-Wagner, A and Ferté, A and Flaugher, B and Fosalba, P and Frieman, J and García-Bellido, J and Gaztanaga, E and Giannini, G and Gutierrez, G and Hartley, W G and Herner, K and Hinton, S R and Hollowood, D L and Honscheid, K and Huterer, D and Krause, E and Kuehn, K and Lahav, O and Lima, M and Marshall, J L and Mena-Fernández, J and Miquel, R and Mohr, J J and Muir, J and Myles, J and Ogando, R L C and Pieres, A and Malagón, A A Plazas and Porredon, A and Prat, J and Raveri, M and Rodriguez-Monroy, M and Roodman, A and Samuroff, S and Sanchez, E and Cid, D Sanchez and Scarpine, V and Sevilla-Noarbe, I and Smith, M and Soares-Santos, M and Suchyta, E and Tarle, G and Vikram, V and Weaverdyck, N and Wiseman, P and Zhang, Y (2025) Dark Energy Survey Year 6 Results : Cell-based Coadds and Metadetection Weak Lensing Shape Catalogue. Monthly Notices of the Royal Astronomical Society, 543 (4). pp. 4156-4186. ISSN 0035-8711

Abstract

We present the metadetection weak lensing galaxy shape catalogue from the 6-yr Dark Energy Survey (DES Y6) imaging data. This data set is the final release from DES, spanning 4422 deg of the southern sky. We describe how the catalogue was constructed, including the two new major processing steps, cell-based image coaddition, and shear measurements with metadetection. The DES Y6 M etadetection weak lensing shape catalogue consists of 151 922 791 galaxies detected over bands, with an effective number density of = 8.22 galaxies per arcmin and shape noise of . We carry out a suite of validation tests on the catalogue, including testing for point spread function (PSF) leakage, testing for the impact of PSF modelling errors, and testing the correlation of the shear measurements with galaxy, PSF, and survey properties. In addition to demonstrating that our catalogue is robust for weak lensing science, we use the DES Y6 image simulation suite to estimate the overall multiplicative shear bias of our shear measurement pipeline. We find no detectable multiplicative bias at the roughly half-per cent level, with , at uncertainty. This is the first time both cell-based coaddition and M etadetection algorithms are applied to observational data, paving the way to the Stage-IV weak lensing surveys.