The impact of spectroscopic incompleteness in direct calibration of redshift distributions for weak lensing surveys

Journal Article · 27 June 2020 · Monthly Notices of the Royal Astronomical Society

DOI: https://doi.org/10.1093/mnras/staa1812 · OSTI ID:1638777

Hartley, W. G. ^[1]; Chang, C.  ^[2]; Samani, S. ^[3]; Carnero Rosell, A. ^[4]; Davis, T. M. ^[5]; Hoyle, B. ^[6]; Gruen, D. ^[7]; Asorey, J. ^[4]; Gschwend, J. ^[8]; Lidman, C. ^[9]; Kuehn, K. ^[10]; King, A. ^[5]; Rau, M. M. ^[11]; Wechsler, R. H. ^[7]; DeRose, J. ^[12]; Hinton, S. R. ^[5]; Whiteway, L. ^[3]; Abbott, T. C. ^[13]; Aguena, M. ^[14]; Allam, S. ^[15] ; Annis, J. ^[15]; Avila, S. ^[16]; Bernstein, G. M. ^[17]; Bertin, E. ^[18]; Bridle, S. L. ^[19]; Brooks, D. ^[3]; Burke, D. L. ^[20]; Kind, M. Carrasco ^[21]; Carretero, J. ^[22]; Castander, F. J. ^[23]; Cawthon, R. ^[24]; Costanzi, M. ^[25]; da Costa, L. N. ^[8]; Desai, S. ^[26]; Diehl, H. T. ^[15]; Dietrich, J. P. ^[27]; Flaugher, B. ^[15]; Fosalba, P. ^[23]; Frieman, J. ^[28]; García-Bellido, J. ^[16]; Gaztanaga, E. ^[23]; Gerdes, D. W. ^[29]; Gruendl, R. A. ^[21]; Gutierrez, G. ^[15]; Hollowood, D. L. ^[30]; Honscheid, K. ^[31]; James, D. J. ^[32]; Kent, S. ^[33]; Krause, E. ^[34]; Kuropatkin, N. ^[15]; Lahav, O. ^[3]; Lima, M. ^[35]; Maia, M. G. ^[8]; Marshall, J. L. ^[36]; Melchior, P. ^[37]; Menanteau, F. ^[21]; Miquel, R. ^[38]; Ogando, R. C. ^[8]; Palmese, A. ^[33]; Paz-Chinchón, F. ^[21]; Plazas, A. A. ^[37]; Roodman, A. ^[20]; Rykoff, E. S. ^[20]; Sanchez, E. ^[4]; Scarpine, V. ^[15]; Schubnell, M. ^[39]; Serrano, S. ^[23]; Sevilla-Noarbe, I. ^[4]; Smith, M. ^[40]; Soares-Santos, M. ^[41]; Suchyta, E. ^[42]; Tarle, G. ^[22]; Troxel, M. A. ^[43]; Tucker, D. L. ^[15]; Varga, T. N. ^[6]; Weller, J. ^[6]; Wilkinson, R. D. ^[44]

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1. Department of Physics & Astronomy, University College London, Gower Street, London WC1E 6BT, UK;Département de Physique Théorique and Center for Astroparticle Physics, Université de Genève, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland;Department of Physics, ETH Zurich, Wolfgang-Pauli-Strasse 16, CH-8093 Zurich, Switzerland
2. Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637, USA;Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637, USA
3. Department of Physics & Astronomy, University College London, Gower Street, London WC1E 6BT, UK
4. Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Madrid, 28040, Spain
5. School of Mathematics and Physics, University of Queensland, Brisbane, QLD 4072, Australia
6. Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, D-85748 Garching, Germany;Fakultät für Physik, Universitäts-Sternwarte, Ludwig-Maximilians Universität München, Scheinerstr. 1, D-81679 München, Germany
7. Department of Physics, Stanford University, 382 Via Pueblo Mall, Stanford, CA 94305, USA;Kavli Institute for Particle Astrophysics & Cosmology, P. O. Box 2450, Stanford University, Stanford, CA 94305, USA;SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
8. Laboratório Interinstitucional de e-Astronomia - LIneA, Rua Gal. José Cristino 77, Rio de Janeiro, RJ - 20921-400, Brazil;Observatório Nacional, Rua Gal. José Cristino 77, Rio de Janeiro, RJ - 20921-400, Brazil
9. The Research School of Astronomy and Astrophysics, Australian National University, ACT 2601, Australia
10. Australian Astronomical Optics, Macquarie University, North Ryde, NSW 2113, Australia;Lowell Observatory, 1400 Mars Hill Rd, Flagstaff, AZ 86001, USA
11. McWilliams Center for Cosmology, Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA
12. Department of Astronomy, University of California, Berkeley, 501 Campbell Hall, Berkeley, CA 94720, USA;Santa Cruz Institute for Particle Physics, Santa Cruz, CA 95064, USA
13. Cerro Tololo Inter-American Observatory, National Optical Astronomy Observatory, Casilla 603, La Serena, Chile
14. Laboratório Interinstitucional de e-Astronomia - LIneA, Rua Gal. José Cristino 77, Rio de Janeiro, RJ - 20921-400, Brazil;Departamento de Física Matemática, Instituto de Física, Universidade de São Paulo, CP 66318, São Paulo, SP, 05314-970, Brazil
15. Fermi National Accelerator Laboratory, P. O. Box 500, Batavia, IL 60510, USA
16. Instituto de Fisica Teorica UAM/CSIC, Universidad Autonoma de Madrid, E-28049 Madrid, Spain
17. Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA
18. CNRS, UMR 7095, Institut d’Astrophysique de Paris, F-75014 Paris, France;Institut d’Astrophysique de Paris, Sorbonne Universités, UPMC Univ Paris 06, UMR 7095, F-75014 Paris, France
19. Jodrell Bank Center for Astrophysics, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
20. Kavli Institute for Particle Astrophysics & Cosmology, P. O. Box 2450, Stanford University, Stanford, CA 94305, USA;SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
21. Department of Astronomy, University of Illinois at Urbana-Champaign, 1002 W. Green Street, Urbana, IL 61801, USA;National Center for Supercomputing Applications, 1205 West Clark St., Urbana, IL 61801, USA
22. Institut de Física d’Altes Energies (IFAE), The Barcelona Institute of Science and Technology, Campus UAB, E-08193 Bellaterra (Barcelona), Spain
23. Institut d’Estudis Espacials de Catalunya (IEEC), E-08034 Barcelona, Spain;Institute of Space Sciences (ICE, CSIC), Campus UAB, Carrer de Can Magrans, s/n, E-08193 Barcelona, Spain
24. Department of Physics, 2320 Chamberlin Hall, University of Wisconsin-Madison, 1150 University Avenue, Madison, WI 53706-1390, USA
25. INAF-Osservatorio Astronomico di Trieste, via G. B. Tiepolo 11, I-34143 Trieste, Italy;Institute for Fundamental Physics of the Universe, Via Beirut 2, I-34014 Trieste, Italy
26. Department of Physics, IIT Hyderabad, Kandi, Telangana 502285, India
27. Faculty of Physics, Ludwig-Maximilians-Universität, Scheinerstr 1, D-81679 Munich, Germany
28. Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637, USA;Fermi National Accelerator Laboratory, P. O. Box 500, Batavia, IL 60510, USA
29. Department of Astronomy, University of Michigan, Ann Arbor, MI 48109, USA;Department of Physics, University of Michigan, Ann Arbor, MI 48109, USA
30. Santa Cruz Institute for Particle Physics, Santa Cruz, CA 95064, USA
31. Center for Cosmology and Astro-Particle Physics, The Ohio State University, Columbus, OH 43210, USA;Department of Physics, The Ohio State University, Columbus, OH 43210, USA
32. Center for Astrophysics |Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USA
33. Fermi National Accelerator Laboratory, P. O. Box 500, Batavia, IL 60510, USA;Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637, USA
34. Department of Astronomy/Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721-0065, USA
35. Departamento de Física Matemática, Instituto de Física, Universidade de São Paulo, CP 66318, São Paulo, SP, 05314-970, Brazil;Laboratório Interinstitucional de e-Astronomia - LIneA, Rua Gal. José Cristino 77, Rio de Janeiro, RJ - 20921-400, Brazil
36. George 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
37. Department of Astrophysical Sciences, Princeton University, Peyton Hall, Princeton, NJ 08544, USA
38. Australian Astronomical Optics, Macquarie University, North Ryde, NSW 2113, Australia;Institució Catalana de Recerca i Estudis Avançats, E-08010 Barcelona, Spain
39. Department of Physics, University of Michigan, Ann Arbor, MI 48109, USA
40. School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ, UK
41. Department of Physics, Brandeis University,415 South Street, Waltham MA 02453, USA
42. Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
43. Department of Physics, Duke University Durham, NC 27708, USA
44. Department of Physics and Astronomy, Pevensey Building, University of Sussex, Brighton BN1 9QH, UK

Obtaining accurate distributions of galaxy redshifts is a critical aspect of weak lensing cosmology experiments. One of the methods used to estimate and validate redshift distributions is to apply weights to a spectroscopic sample, so that their weighted photometry distribution matches the target sample. Herein, we estimate the selection bias in redshift that is introduced in this procedure. We do so by simulating the process of assembling a spectroscopic sample (including observer-assigned confidence flags) and highlight the impacts of spectroscopic target selection and redshift failures. We use the first year (Y1) weak lensing analysis in Dark Energy Survey (DES) as an example data set but the implications generalize to all similar weak lensing surveys. We find that using colour cuts that are not available to the weak lensing galaxies can introduce biases of up to Δz ~ 0.04 in the weighted mean redshift of different redshift intervals (Δz ~ 0.015 in the case most relevant to DES). To assess the impact of incompleteness in spectroscopic samples, we select only objects with high observer-defined confidence flags and compare the weighted mean redshift with the true mean. We find that the mean redshift of the DES Y1 weak lensing sample is typically biased at the Δz = 0.005–0.05 level after the weighting is applied. The bias we uncover can have either sign, depending on the samples and redshift interval considered. For the highest redshift bin, the bias is larger than the uncertainties in the other DES Y1 redshift calibration methods, justifying the decision of not using this method for the redshift estimations. We discuss several methods to mitigate this bias.

• Research Organization: SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Univ. of Michigan, Ann Arbor, MI (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP); National Science Foundation (NSF); USDOE
• Contributing Organization: DES Collaboration
• Grant/Contract Number: AC02-07CH11359; AST-138766; AST-1536171; AC05-00OR22725; SC0019193
• OSTI ID: 1638777
• Alternate ID(s): OSTI ID: 1616311; OSTI ID: 1661213; OSTI ID: 1784539
• Report Number(s): arXiv:2003.10454; FERMILAB-PUB-20-106-AE; DES-2019-0498; oai:inspirehep.net:1787863; TRN: US2106439
• Journal Information: Monthly Notices of the Royal Astronomical Society, Vol. 496, Issue 4; ISSN 0035-8711
• Publisher: Royal Astronomical SocietyCopyright Statement
• Country of Publication: United States
• Language: English