The Dark Energy Survey Data Release 2

We present the second public data release of the Dark Energy Survey, DES DR2, based on optical/near-infrared imaging by the Dark Energy Camera mounted on the 4 m Blanco telescope at Cerro Tololo Inter-American Observatory in Chile. DES DR2 consists of reduced single-epoch and coadded images, a source catalog derived from coadded images, and associated data products assembled from 6 yr of DES science operations. This release includes data from the DES wide-area survey covering similar to 5000 deg(2) of the southern Galactic cap in five broad photometric bands, grizY. DES DR2 has a median delivered point-spread function FWHM of g = 1.11 '', r = 0.95 '', i = 0.88 '', z = 0.83 '', and Y = 0.'' 90, photometric uniformity with a standard deviation of < 3 mmag with respect to Gaia DR2 G band, a photometric accuracy of similar to 11 mmag, and a median internal astrometric precision of similar to 27 mas. The median coadded catalog depth for a 1.'' 95 diameter aperture at signal-to-noise ratio = 10 is g = 24.7, r = 24.4, i = 23.8, z = 23.1, and Y = 21.7 mag. DES DR2 includes similar to 691 million distinct astronomical objects detected in 10,169 coadded image tiles of size 0.534 deg(2) produced from 76,217 single-epoch images. After a basic quality selection, benchmark galaxy and stellar samples contain 543 million and 145 million objects, respectively. These data are accessible through several interfaces, including interactive image visualization tools, web-based query clients, image cutout servers, and Jupyter notebooks. DES DR2 constitutes the largest photometric data set to date at the achieved depth and photometric precision.

Automated summary

The second public data release of the Dark Energy Survey, DES DR2, includes reduced single-epoch and coadded images, a source catalog and associated data products assembled from 6 years of DES science operations. Covering approximately 5000 deg(2) of the southern Galactic cap in five broad photometric bands, DES DR2 offers photometric uniformity and accuracy, with a median delivered point-spread function FWHM and internal astrometric precision. The dataset includes data from 691 million distinct astronomical objects accessible through various interfaces, making it the largest photometric data set to date at the achieved depth and photometric precision.