Abstract
Galaxy cross-correlations with high-fidelity redshift samples hold the potential to precisely calibrate systematic photometric redshift uncertainties arising from the unavailability of complete and representative training and validation samples of galaxies. However, application of this technique in the Dark Energy Survey (DES) is hampered by the relatively low number density, small area, and modest redshift overlap between photometric and spectroscopic samples. We propose instead using photometric catalogues with reliable photometric redshifts for photo-z calibration via cross-correlations. We verify the viability of our proposal using redMaPPer clusters from the Sloan Digital Sky Survey (SDSS) to successfully recover the redshift distribution of SDSS spectroscopic galaxies.We demonstrate how to combine photo-z with cross-correlation data to calibrate photometric redshift biases while marginalizing over possible clustering bias evolution in either the calibration or unknown photometric samples. We apply our method to DES Science Verification (DES SV) data in order to constrain the photometric redshift distribution of a galaxy sample selected for weak lensing studies, constraining the mean of the tomographic redshift distributions to a statistical uncertainty of Δz ~ ±0.01. We forecast that our proposal can, in principle, control photometric redshift uncertainties in DES weak lensing experiments at a level near the intrinsic statistical noise of the experiment over the range of redshifts where redMaPPer clusters are available. Our results provide strong motivation to launch a programme to fully characterize the systematic errors from bias evolution and photo-z shapes in our calibration procedure.
| Original language | English |
|---|---|
| Pages (from-to) | 2196-2208 |
| Number of pages | 13 |
| Journal | Monthly Notices of the Royal Astronomical Society |
| Volume | 477 |
| Issue number | 2 |
| DOIs | |
| State | Published - Jun 21 2018 |
Funding
CPD would like to acknowledge Enrique Gaztanaga, Marco Gatti, Pauline Vielzeuf, Ross Cawthon, and Àlex Alarcón for many fruitful conversations. He would also like to thank Ben Hoyle, Huan Lin, Ramon Miquel, and Michael Troxel for their many suggestions, which tremendously improved this paper. This work is partially supported by the Northern California Chapter of the ARCS Foundation, as well as by the U.S. Department of Energy under contract number DE-AC02-76-SF00515. ER is supported by DOE grant DESC0015975 and by the Sloan Foundation, grant FG-2016-6443. 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, Fi-nanciadora 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 Forschungsge-meinschaft, and the Collaborating Institutions in the DES. CPD would like to acknowledge Enrique Gaztanaga, Marco Gatti, PaulineVielzeuf, RossCawthon, and AlexAlarco? formany fruitful conversations. He would also like to thank Ben Hoyle, Huan Lin, Ramon Miquel, and Michael Troxel for their many suggestions, which tremendously improved this paper. This work is partially supported by the Northern California Chapter of the ARCS Foundation, as well as by the U.S. Department of Energy under contract numberDE-AC02-76-SF00515. ER is supported by DOE grantDESC0015975 and by the Sloan Foundation, grant FG-2016-6443. 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 NationalCenter 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 andAstro-Particle Physics at the Ohio State University, the Mitchell Institute for Fundamental Physics and Astronomy at Texas A&MUniversity, 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 DES. 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, TexasA&MUniversity, and the OzDESMembership Consortium. 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, ESP2015-88861, FPA2015-68048, SEV-2012-0234, SEV-2012-0249, 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. We are grateful for the extraordinary contributions of our CTIO colleagues and the DECam Construction, Commissioning and Science Verification teams in achieving the excellent instrument and telescope conditions that have made this work possible. The success of this project also relies critically on the expertise and dedication of the DES Data Management group 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, ESP2015-88861, FPA2015-68048, SEV-2012-0234, SEV-2012-0249, 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.
Keywords
- Galaxies: Clusters: General
- Galaxies: Distances and redshifts