Dark Energy Survey Year 1 Results: Photometric Data Set for Cosmology
A. Drlica-Wagner, I. Sevilla-Noarbe, E. S. Rykoff, R. A. Gruendl, B. Yanny, D. L. Tucker, B. Hoyle, A. Carnero Rosell, G. M. Bernstein, K. Bechtol, M. R. Becker, A. Benoit-Levy, E. Bertin, M. Carrasco Kind, C. Davis, J. de Vicente, H. T. Diehl, D. Gruen, W. G. Hartley, B. Leistedt, T. S. Li, J. L. Marshall, E. Neilsen, M. M. Rau, E. Sheldon, J. Smith, M. A. Troxel, S. Wyatt, Y. Zhang, T. M. C. Abbott, F. B. Abdalla, S. Allam, M. Banerji, D. Brooks, E. Buckley-Geer, D. L. Burke, D. Capozzi, J. Carretero, C. E. Cunha, C. B. D'Andrea, L. N. da Costa, D. L. DePoy, S. Desai, J. P. Dietrich, P. Doel, A. E. Evrard, A. Fausti Neto, B. Flaugher, P. Fosalba, J. Frieman, J. Garcia-Bellido, D. W. Gerdes, T. Giannantonio, J. Gschwend, G. Gutierrez, K. Honscheid, D. J. James, T. Jeltema, K. Kuehn, S. Kuhlmann, N. Kuropatkin, O. Lahav, M. Lima, H. Lin, M. A. G. Maia, P. Martini, R. G. McMahon, P. Melchior, F. Menanteau, R. Miquel, R. C. Nichol, R. L. C. Ogando, A. A. Plazas, A. K. Romer, A. Roodman, E. Sanchez, V. Scarpine, R. Schindler, M. Schubnell, M. Smith, R. C. Smith, M. Soares-Santos, F. Sobreira, E. Suchyta, G. Tarle, V. Vikram, A. R. Walker, R. H. Wechsler, J. Zuntz
TL;DR
The paper documents the production, composition, and validation of DES Year 1 GOLD, a cosmology-ready photometric data set assembled from Y1A1 imaging. It details the construction of a multi-band object catalog (from Y1A1 COADD), a refined photometric calibration using nightly zeropoints and stellar-locus regression, and a suite of ancillary maps (survey depth, observing conditions) plus high-level quantities like star-galaxy classification and photometric redshifts. It reports a wide-area catalog of ~137 million objects over ~1800 deg^2, with 10σ galaxy depth reaching g=23.4, r=23.2, i=22.5, z=21.8, Y=20.1, and absolute calibration accuracy better than 2%. The data set, integrated with DESDM processing and coaddition, provides the necessary fidelity and diagnostics to enable robust cosmological measurements at z ≲ 1.
Abstract
We describe the creation, content, and validation of the Dark Energy Survey (DES) internal year-one cosmology data set, Y1A1 GOLD, in support of upcoming cosmological analyses. The Y1A1 GOLD data set is assembled from multiple epochs of DES imaging and consists of calibrated photometric zeropoints, object catalogs, and ancillary data products - e.g., maps of survey depth and observing conditions, star-galaxy classification, and photometric redshift estimates - that are necessary for accurate cosmological analyses. The Y1A1 GOLD wide-area object catalog consists of ~137 million objects detected in coadded images covering ~1800 deg$^2$ in the DES grizY filters. The 10σ limiting magnitude for galaxies is g = 23.4, r = 23.2, i = 22.5, z = 21.8, and Y = 20.1. Photometric calibration of Y1A1 GOLD was performed by combining nightly zeropoint solutions with stellar-locus regression, and the absolute calibration accuracy is better than 2% over the survey area. DES Y1A1 GOLD is the largest photometric data set at the achieved depth to date, enabling precise measurements of cosmic acceleration at z $\lesssim$ 1.