Abstract
Abstract We describe an updated calibration and diagnostic framework, Balrog, used to directly sample the selection and photometric biases of the Dark Energy Survey (DES) Year 3 (Y3) data set. We systematically inject onto the single-epoch images of a random 20% subset of the DES footprint an ensemble of nearly 30 million realistic galaxy models derived from DES Deep Field observations. These augmented images are analyzed in parallel with the original data to automatically inherit measurement systematics that are often too difficult to capture with generative models. The resulting object catalog is a Monte Carlo sampling of the DES transfer function and is used as a powerful diagnostic and calibration tool for a variety of DES Y3 science, particularly for the calibration of the photometric redshifts of distant “source” galaxies and magnification biases of nearer “lens” galaxies. The recovered Balrog injections are shown to closely match the photometric property distributions of the Y3 GOLD catalog, particularly in color, and capture the number density fluctuations from observing conditions of the real data within 1% for a typical galaxy sample. We find that Y3 colors are extremely well calibrated, typically within ∼1–8 mmag, but for a small subset of objects, we detect significant magnitude biases correlated with large overestimates of the injected object size due to proximity effects and blending. We discuss approaches to extend the current methodology to capture more aspects of the transfer function and reach full coverage of the survey footprint for future analyses.
Highlights
Wide-field imaging surveys have revolutionized modern astronomy
We cut on match flag 1.5 asec < 2 as we found that only 0.1% and 0.5% of Year 3 (Y3) GOLD objects were separated at distances less than 1.5 at i magnitudes of 21 and 22.5 respectively
We have presented here the suite of Dark Energy Survey (DES) Y3 Balrog simulations and resulting object catalogs used in downstream Y3 analyses
Summary
S. Everett,1 B. Yanny,2 N. Kuropatkin,2 E. M. Huff,3 Y. Zhang,2 J. Myles,4, 5, 6 A. Masegian,7 J. Elvin-Poole,8, 9 S. Allam,2 G. M. Bernstein,10 I. Sevilla-Noarbe,11 M. Splettstoesser,12 E. Sheldon,13 M. Jarvis,10 A. Amon,5 I. Harrison,14, 15 A. Choi,8 W. G. Hartley,16 A. Alarcon,17 C. Sanchez,10 D. Gruen,4, 5, 6 K. Eckert,10 J. Prat,18 M. Tabbutt,19 V. Busti,20, 21 M. R. Becker,17 N. MacCrann,22 H. T. Diehl,2 D. L. Tucker,2 E. Bertin,23, 24 T. Jeltema,1 A. Drlica-Wagner,18, 2, 7 R. A. Gruendl,25, 26 K. Bechtol,19 A. Carnero Rosell,27, 28 T. M. C. Abbott,29 M. Aguena,20, 21 J. Annis,2 D. Bacon,30 S. Bhargava,12 D. Brooks,31 D. L. Burke,5, 6 M. Carrasco Kind,25, 26 J. Carretero,32 F. J. Castander,33, C. Conselice,15, M. Costanzi,36, L. N. da Costa,21, M. E. S. Pereira,39 J. De Vicente,11 J. DeRose,40, 1 S. Desai,41 T. F. Eifler,42, 3 A. E. Evrard,43, I. Ferrero,44 P. Fosalba,33, 34 J. Frieman,2, 7 J. Garcıa-Bellido,45 E. Gaztanaga,33, 34 D. W. Gerdes,43, 39 G. Gutierrez,2 S. R. Hinton,46 D. L. Hollowood,1 K. Honscheid,8, 9 D. Huterer,39 D. J. James,47 S. Kent,2, 7 E. Krause,42 K. Kuehn,48, 49 O. Lahav,31 M. Lima,20, 21 H. Lin,2 M. A. G. Maia,21, 38 J. L. Marshall,50 P. Melchior,51 F. Menanteau,25, 26 R. Miquel,52, 32 J. J. Mohr,53, 54 R. Morgan,19 J. Muir,5 R. L. C. Ogando,21, 38 A. Palmese,2, 7 F. Paz-Chinchon,55, 26 A. A. Plazas,51 M. Rodriguez-Monroy,11 A. K. Romer,12 A. Roodman,5, 6 E. Sanchez,11 V. Scarpine,2 S. Serrano,33, 34 M. Smith,56 M. Soares-Santos,39 E. Suchyta,57 M. E. C. Swanson,26 G. Tarle,39 C. To,4, 5, 6 M. A. Troxel,58 T. N. Varga,54, 59 J. Weller,54, 59 R.D. Wilkinson,12 13Brookhaven National Laboratory, Bldg 510, Upton, NY 11973, USA 14Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, UK 15Jodrell Bank Center for Astrophysics, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester, M13 Geneva, Switzerland 17Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL 60439, USA 18Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637, USA 19Physics Department, 2320 Chamberlin Hall, University of Wisconsin-Madison, 1150 University Avenue Madison, WI 53706-1390 20Departamento de Fısica Matematica, Instituto de Fısica, Universidade de Sao Paulo, CP 66318, Sao Paulo, SP, 05314-970, Brazil 21Laboratorio Interinstitucional de e-Astronomia - LIneA, Rua Gal. Jose Cristino 77, Rio de Janeiro, RJ - 20921-400, Brazil 22Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge CB3 0WA, UK 23CNRS, UMR 7095, Institut d’Astrophysique de Paris, F-75014, Paris, France 24Sorbonne Universites, UPMC Univ Paris 06, UMR 7095, Institut d’Astrophysique de Paris, F-75014, Paris, France 25Department of Astronomy, University of Illinois at Urbana-Champaign, 1002 W. Green Street, Urbana, IL 61801, USA 26National Center for Supercomputing Applications, 1205 West Clark St., Urbana, IL 61801, USA 27Instituto de Astrofisica de Canarias, E-38205 La Laguna, Tenerife, Spain 28Universidad de La Laguna, Dpto. Astrofısica, E-38206 La Laguna, Tenerife, Spain 29Cerro Tololo Inter-American Observatory, NSF’s NOIRLab, Casilla 603, La Serena, Chile This document was prepared by DES Collaboration using the resources of the Fermi National Accelerator Laboratory (Fermilab), a U.S Department of Energy, Office of Science, HEP User Facility. Fermilab is managed by Fermi Research Alliance, LLC (FRA), acting under Contract No DE-AC02-07CH11359. 30Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth, PO1 3FX, UK 31Department of Physics & Astronomy, University College London, Gower Street, London, WC1E 6BT, UK 32Institut de Fısica d’Altes Energies (IFAE), The Barcelona Institute of Science and Technology, Campus UAB, 08193 Bellaterra, Spain 33Institut d’Estudis Espacials de Catalunya (IEEC), 08034 Barcelona, Spain 34Institute of Space Sciences (ICE, CSIC), Campus UAB, Carrer de Can Magrans, s/n, 08193 Barcelona, Spain 35University of Nottingham, School of Physics and Astronomy, Nottingham NG7 2RD, UK 36INAF-Osservatorio Astronomico di Trieste, via G. B. Tiepolo 11, I-34143 Trieste, Italy 37Institute for Fundamental Physics of the Universe, Via Beirut 2, 34014 Trieste, Italy 38Observatorio Nacional, Rua Gal. Jose Cristino 77, Rio de Janeiro, RJ - 20921-400, Brazil 39Department of Physics, University of Michigan, Ann Arbor, MI 48109, USA 40Department of Astronomy, University of California, Berkeley, 501 Campbell Hall, Berkeley, CA 94720, USA 41Department of Physics, IIT Hyderabad, Kandi, Telangana 502285, India 42Department of Astronomy/Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721-0065, USA 43Department of Astronomy, University of Michigan, Ann Arbor, MI 48109, USA 44Institute of Theoretical Astrophysics, University of Oslo. P.O. Box 1029 Blindern, NO-0315 Oslo, Norway 45Instituto de Fisica Teorica UAM/CSIC, Universidad Autonoma de Madrid, 28049 Madrid, Spain 46School of Mathematics and Physics, University of Queensland, Brisbane, QLD 4072, Australia 47Center for Astrophysics | Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USA 48Australian Astronomical Optics, Macquarie University, North Ryde, NSW 2113, Australia 49Lowell Observatory, 1400 Mars Hill Rd, Flagstaff, AZ 86001, USA 50George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, and Department of Physics and Astronomy, Texas A&M University, College Station, TX 77843, USA 51Department of Astrophysical Sciences, Princeton University, Peyton Hall, Princeton, NJ 08544, USA 52Institucio Catalana de Recerca i Estudis Avancats, E-08010 Barcelona, Spain 53Faculty of Physics, Ludwig-Maximilians-Universitat, Scheinerstr. 1, 81679 Munich, Germany 54Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, 85748 Garching, Germany 55Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK 56School of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ, UK 57Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 58Department of Physics, Duke University Durham, NC 27708, USA 59Universitats-Sternwarte, Fakultat fur Physik, Ludwig-Maximilians Universitat Munchen, Scheinerstr. 1, 81679 Munchen, Germany (Received XXX, 2020; Revised XXX, 2020; Accepted XXX, 2020) Submitted to ApJS
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