We describe the Dark Energy Survey (DES) photometric data set assembled from the first three years of science operations to support DES Year 3 cosmologic analyses, and provide usage notes aimed at the broad astrophysics community. Y3 GOLD improves on previous releases from DES, Y1 GOLD, and Data Release 1 (DES DR1), presenting an expanded and curated data set that incorporates algorithmic developments in image detrending and processing, photometric calibration, and object classification. Y3 GOLD comprises nearly 5000 deg² of grizY imaging in the south Galactic cap, including nearly 390 million objects, with depth reaching a signal-to-noise ratio ∼10 for extended objects up to i _AB ∼ 23.0, and top-of-the-atmosphere photometric uniformity <3 mmag. Compared to DR1, photometric residuals with respect to Gaia are reduced by 50%, and per-object chromatic corrections are introduced. Y3 GOLD augments DES DR1 with simultaneous fits to multi-epoch photometry for more robust galactic color measurements and corresponding photometric redshift estimates. Y3 GOLD features improved morphological star–galaxy classification with efficiency >98% and purity >99% for galaxies with 19 < i _AB < 22.5. Additionally, it includes per-object quality information, and accompanying maps of the footprint coverage, masked regions, imaging depth, survey conditions, and astrophysical foregrounds that are used to select the cosmologic analysis samples.

我们描述了从前三年科学运作中收集的暗能量调查 (DES) 光度数据集，以支持 DES 3 年宇宙学分析，并提供针对广大天体物理学界的使用说明。Y3 GOLD对 DES、Y1 GOLD和数据版本 1 (DES DR1) 的先前版本进行了改进，提供了一个扩展和精选的数据集，其中包含图像去趋势和处理、光度校准和对象分类方面的算法发展。Y3 GOLD包含近 5000 度²的grizY南银河帽的成像，包括近 3.9 亿个物体，深度达到信噪比∼10，对于高达i _AB ∼ 23.0 的扩展对象，以及大气顶部光度均匀性 <3 mmag。与 DR1 相比，Gaia 的光度残差减少了 50%，并引入了每个对象的色度校正。Y3 GOLD增强了 DES DR1，同时适合多历元光度测量，以实现更强大的星系颜色测量和相应的光度红移估计。Y3 GOLD具有改进的形态星-星系分类，对于 19 < i _AB的星系，效率 >98%，纯度 >99%< 22.5。此外，它还包括每个对象的质量信息，以及用于选择宇宙学分析样本的足迹覆盖范围、掩蔽区域、成像深度、调查条件和天体物理前景的随附地图。