Dark Energy Survey Year 3 Results: Weak Lensing Shape Catalogue

TL;DR

This paper presents the Dark Energy Survey Year 3 weak lensing shape catalogue, detailing data analysis, calibration, and systematic tests for over 100 million galaxies to support cosmological studies.

Contribution

It introduces an improved self-calibrating shear measurement pipeline and provides a comprehensive characterization of the Year 3 galaxy shape catalogue.

Findings

Catalogue contains over 100 million galaxies with high shape measurement quality.

Extensive null tests confirm the catalogue's robustness against systematics.

Achieved a source density of 5.59 galaxies per arcmin^2 with low shape noise.

Abstract

We present and characterise the galaxy shape catalogue from the first 3 years of Dark Energy Survey (DES) observations, over an effective area of ~4143 deg$^2$ of the southern sky. We describe our data analysis process and our self-calibrating shear measurement pipeline METACALIBRATION, which builds and improves upon the pipeline used in the DES Year 1 analysis in several aspects. The DES Year 3 weak-lensing shape catalogue consists of 100,204,026 galaxies, measured in the $riz$ bands, resulting in a weighted source number density of $n_{\rm eff} = 5.59$ gal/arcmin$ ^{2}$ and corresponding shape noise $\sigma_e = 0.261$. We perform a battery of internal null tests on the catalogue, including tests on systematics related to the point-spread function (PSF) modelling, spurious catalogue B-mode signals, catalogue contamination, and galaxy properties.