Abstract
In this paper, we describe the first public data release of the Dark Energy Survey, DES DR1, consisting of reduced single-epoch images, co-added images, co-added source catalogs, and associated products and services assembled over the first 3 yr of DES science operations. DES DR1 is based on optical/near-infrared imaging from 345 distinct nights (2013 August to 2016 February) by the Dark Energy Camera mounted on the 4 m Blanco telescope at the Cerro Tololo Inter-American Observatory in Chile. We release data from the DES wide-area survey covering ~5000 deg2 of the southern Galactic cap in five broad photometric bands, grizY. DES DR1 has a median delivered point-spread function of g=1.12, r = 0.96, i = 0.88, z = 0.84, and Y = 0$"\atop{.}$90 FWHM, a photometric precision of <1% in all bands, and an astrometric precision of 151 $\,\mathrm{mas}$. The median co-added catalog depth for a 1$"\atop{.}$95 diameter aperture at signal-to-noise ratio (S/N) = 10 is g = 24.33, r = 24.08, i = 23.44, z = 22.69, and Y = 21.44 $\,\mathrm{mag}$ . DES DR1 includes nearly 400 million distinct astronomical objects detected in ~10,000 co-add tiles of size 0.534 deg2 produced from ~39,000 individual exposures. Benchmark galaxy and stellar samples contain ~310 million and ~80 million objects, respectively, following a basic object quality selection. Lastly, these data are accessible through a range of interfaces, including query web clients, image cutout servers, jupyter notebooks, and an interactive co-add image visualization tool. DES DR1 constitutes the largest photometric data set to date at the achieved depth and photometric precision.