Abstract
Wide-field imaging surveys such as the Dark Energy Survey (DES) rely on coarse measurements of spectral energy distributions in a few filters to estimate the redshift distribution of source galaxies. In this regime, sample variance, shot noise, and selection effects limit the attainable accuracy of redshift calibration and thus of cosmological constraints. We present a new method to combine wide-field, few-filter measurements with catalogues from deep fields with additional filters and sufficiently low photometric noise to break degeneracies in photometric redshifts. The multiband deep field is used as an intermediary between wide-field observations and accurate redshifts, greatly reducing sample variance, shot noise, and selection effects. Our implementation of the method uses self-organizing maps to group galaxies into phenotypes based on their observed fluxes, and is tested using a mock DES catalogue created from N-body simulations. It yields a typical uncertainty on the mean redshift in each of five tomographic bins for an idealized simulation of the DES Year 3 weak-lensing tomographic analysis of σΔz = 0.007, which is a 60 per cent improvement compared to the Year 1 analysis. Although the implementation of the method is tailored to DES, its formalism can be applied to other large photometric surveys with a similar observing strategy.
| Original language | English |
|---|---|
| Pages (from-to) | 820-841 |
| Number of pages | 22 |
| Journal | Monthly Notices of the Royal Astronomical Society |
| Volume | 489 |
| Issue number | 1 |
| DOIs | |
| State | Published - Oct 11 2019 |
Funding
The DES data management system is supported by the National Science Foundation under Grant Numbers AST-1138766 and AST-1536171. The DES participants from Spanish institutions are partially supported by MINECO under grants AYA2015-71825, ESP2015-66861, FPA2015-68048, SEV-2016-0588, SEV-2016-0597, and MDM-2015-0509, some of which include ERDF funds from the European Union. IFAE is partially funded by the CERCA program of the Generalitat de Catalunya. Research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Program (FP7/2007-2013) including ERC grant agreements 240672, 291329, and 306478. We acknowledge support from the Australian Research The authors thank Jamie McCullough and numerous members of the DES Collaboration for helpful comments on the manuscript. This work was supported in part by the U.S. Department of Energy under contract number DE-AC02-76SF00515. Support for DG was provided by NASA through Einstein Postdoctoral Fellowship grant number PF5-160138 awarded by the Chandra X-ray Center, which is operated by the Smithsonian Astrophysical Observatory for NASA under contract NAS8-03060. Funding for the DES Projects has been provided by the U.S. Department of Energy, the U.S. National Science Foundation, the Ministry of Science and Education of Spain, the Science and Technology Facilities Council of the United Kingdom, the Higher Education Funding Council for England, the National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign, the Kavli Institute of Cosmological Physics at the University of Chicago, the Center for Cosmology and Astro-Particle Physics at the Ohio State University, the Mitchell Institute for Fundamental Physics and Astronomy at Texas A&M University, Financiadora de Estudos e Projetos, Funda??o Carlos Chagas Filho de Amparo ? Pesquisa do Estado do Rio de Janeiro, Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico and the Minist?rio da Ci?ncia, Tecnologia e Inova??o, the Deutsche Forschungsgemeinschaft and the Collaborating Institutions in the Dark Energy Survey. The Collaborating Institutions are Argonne National Laboratory, the University of California at Santa Cruz, the University of Cambridge, Centro de Investigaciones Energ?ticas, Medioambientales y Tecnol?gicas-Madrid, the University of Chicago, University College London, the DES-Brazil Consortium, the University of Edinburgh, the Eidgen?ssische Technische Hochschule (ETH) Z?rich, Fermi National Accelerator Laboratory, the University of Illinois at Urbana-Champaign, the Institut de Ci?ncies de l'Espai (IEEC/CSIC), the Institut de F?sica d'Altes Energies, Lawrence Berkeley National Laboratory, the Ludwig-Maximilians Universit?t M?nchen and the associated Excellence Cluster Universe, the University of Michigan, the National Optical Astronomy Observatory, the University of Nottingham, The Ohio State University, the University of Pennsylvania, the University of Portsmouth, SLAC National Accelerator Laboratory, Stanford University, the University of Sussex, Texas A&M University, and the OzDES Membership Consortium. Based in part on observations at Cerro Tololo Inter-American Observatory, National Optical Astronomy Observatory, which is operated by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation. The DES data management system is supported by the National Science Foundation under Grant Numbers AST-1138766 and AST-1536171. The DES participants from Spanish institutions are partially supported by MINECO under grants AYA2015-71825, ESP2015-66861, FPA2015-68048, SEV-2016-0588, SEV-2016-0597, and MDM-2015-0509, some of which include ERDF funds from the European Union. IFAE is partially funded by the CERCA program of the Generalitat de Catalunya. Research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Program (FP7/2007-2013) including ERC grant agreements 240672, 291329, and 306478. We acknowledge support from the Australian Research Council Centre of Excellence for All-sky Astrophysics (CAASTRO), through project number CE110001020, and the Brazilian Instituto Nacional de Ci?ncia e Tecnologia (INCT) e-Universe (CNPq grant 465376/2014-2). This paper has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. This paper has gone through internal review by the DES collaboration. Funding for the DES Projects has been provided by the U.S. Department of Energy, the U.S. National Science Foundation, the Ministry of Science and Education of Spain, the Science and Technology Facilities Council of the United Kingdom, the Higher Education Funding Council for England, the National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign, the Kavli Institute of Cosmological Physics at the University of Chicago, the Center for Cosmology and Astro-Particle Physics at the Ohio State University, the Mitchell Institute for Fundamental Physics and Astronomy at Texas A&M University, Financiadora de Estudos e Projetos, Fundac¸ão Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, Conselho Nacional de Desenvolvimento Científico e Tecnológico and the Ministério da Ciência, Tecnologia e Inovac¸ão, the Deutsche Forschungsgemeinschaft and the Collaborating Institutions in the Dark Energy Survey. Council Centre of Excellence for All-sky Astrophysics (CAAS-TRO), through project number CE110001020, and the Brazilian Instituto Nacional de Ciência e Tecnologia (INCT) e-Universe (CNPq grant 465376/2014-2). This paper has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. This work was supported in part by the U.S. Department of Energy under contract number DE-AC02-76SF00515. Support for DG was provided by NASA through Einstein Postdoctoral Fellowship grant number PF5-160138 awarded by the Chandra X-ray Center, which is operated by the Smith-sonian Astrophysical Observatory for NASA under contract NAS8-03060.
| Funders | Funder number |
|---|---|
| Australian Research | |
| Australian Research Council Centre of Excellence for All-sky Astrophysics | |
| Brazilian Instituto Nacional de Ci?ncia e Tecnologia | |
| Brazilian Instituto Nacional de Ciência e Tecnologia | |
| CAAS-TRO | CE110001020 |
| Collaborating Institutions are Argonne National Laboratory | |
| Collaborating Institutions in the Dark Energy Survey | |
| Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico | |
| European Union's Seventh Framework Program | |
| FP7/2007 | |
| Fermi Research Alliance, LLC | DE-AC02-07CH11359 |
| INCT | |
| Institut de Ci?ncies de l'Espai | |
| Institut de F?sica d'Altes Energies | |
| Kavli Institute of Cosmological Physics at the University of Chicago | |
| Ludwig-Maximilians Universit?t M?nchen | |
| Minist?rio da Ci?ncia | |
| Ministry of Science and Education of Spain | |
| Ministério da Ciência | |
| Mitchell Institute for Fundamental Physics and Astronomy at Texas A&M University | |
| National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign | |
| Science and Technology Facilities Council of the United Kingdom | |
| U.S. National Science Foundation | |
| United States Government | |
| National Science Foundation | 1138766, AST-1138766, 240672, 306478, 291329, AST-1536171 |
| U.S. Department of Energy | DE-AC02-76SF00515 |
| National Aeronautics and Space Administration | PF5-160138, NAS8-03060 |
| University of Illinois at Urbana-Champaign | |
| Stanford University | |
| Office of Science | |
| High Energy Physics | |
| Lawrence Berkeley National Laboratory | |
| University of California, Santa Cruz | |
| University of Pennsylvania | |
| Ohio State University | |
| University of Chicago | |
| University of Michigan | |
| Texas A and M University | |
| University of Portsmouth | |
| National Centre for Supercomputing Applications | |
| Seventh Framework Programme | |
| SLAC National Accelerator Laboratory | |
| Higher Education Funding Council for England | |
| Center for Cosmology and Astroparticle Physics, Ohio State University | |
| Engineering Research Centers | |
| Science and Technology Facilities Council | |
| University College London | |
| European Commission | |
| European Research Council | |
| University of Nottingham | |
| University of Sussex | |
| University of Edinburgh | |
| Deutsche Forschungsgemeinschaft | |
| Generalitat de Catalunya | |
| Eidgenössische Technische Hochschule Zürich | |
| Ministerio de Economía y Competitividad | SEV-2016-0588, SEV-2016-0597, ESP2015-66861, MDM-2015-0509, FPA2015-68048, AYA2015-71825 |
| Conselho Nacional de Desenvolvimento Científico e Tecnológico | 465376/2014-2 |
| Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro | |
| Financiadora de Estudos e Projetos | |
| Universidade do Estado do Rio de Janeiro | |
| Instituto Nacional de Ciência e Tecnologia para Excitotoxicidade e Neuroproteção | |
| Ministry of Education and Science of Ukraine | |
| European Regional Development Fund | |
| ARC Centre of Excellence for All-sky Astrophysics |
Keywords
- Dark energy
- Galaxies: distances and redshifts
- Gravitational lensing: weak