Abstract
We present morphological classifications of ~27 million galaxies from the Dark Energy Survey (DES) Data Release 1 (DR1) using a supervised deep learning algorithm. The classification scheme separates: (a) early-type galaxies (ETGs) from late-type galaxies (LTGs); and (b) face-on galaxies from edge-on. Our convolutional neural networks (CNNs) are trained on a small subset of DES objects with previously known classifications. These typically have mr ≤17.7 mag; we model fainter objects to mr < 21.5 mag by simulating what the brighter objects with well-determined classifications would look like if they were at higher redshifts. The CNNs reach 97 per cent accuracy to mr < 21.5 on their training sets, suggesting that they are able to recover features more accurately than the human eye. We then used the trained CNNs to classify the vast majority of the other DES images. The final catalogue comprises five independent CNN predictions for each classification scheme, helping to determine if the CNN predictions are robust or not. We obtain secure classifications for ~87 per cent and 73 per cent of the catalogue for the ETG versus LTG and edge-on versus face-on models, respectively. Combining the two classifications (a) and (b) helps to increase the purity of the ETG sample and to identify edge-on lenticular galaxies (as ETGs with high ellipticity). Where a comparison is possible, our classifications correlate very well with Sérsic index (n), ellipticity (ϵ), and spectral type, even for the fainter galaxies. This is the largest multiband catalogue of automated galaxy morphologies to date.
Original language | English |
---|---|
Pages (from-to) | 1927-1943 |
Number of pages | 17 |
Journal | Monthly Notices of the Royal Astronomical Society |
Volume | 506 |
Issue number | 2 |
DOIs | |
State | Published - Sep 1 2021 |
Funding
This work was supported in part by National Science Foundation (NSF) grant AST-1816330. HDS acknowledges support from the Centro Superior de Investigaciones Cientificas PIE2018-50E099.We are grateful to R. Sheth for a careful reading of the manuscript. 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 StateUniversity, the Mitchell Institute for Fundamental Physics and Astronomy at Texas A&M University, Financiadora de Estudos e Projetos, Fundação Carlos Chagas Filho de Amparoa Pesquisa do Estado do Rio de Janeiro, Conselho Nacional de Desenvolvimento Cientifico e Tecnologico and the Ministerio da Ciencia, Tecnologia e Inovacao, 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 Energeticas, Medioambientales y Tecnologicas - Madrid, the University of Chicago, University College London, the DES-Brazil Consortium, the University of Edinburgh, the Eidgenossische Technische Hochschule (ETH) Zurich, Fermi National Accelerator Laboratory, the University of Illinois at Urbana-Champaign, the Institut de Ciencies de l'Espai (IEEC/CSIC), the Institut de Fisica d'Altes Energies, Lawrence Berkeley National Laboratory, the Ludwig-Maximilians Universitat Munchen and the associated Excellence Cluster Universe, the University of Michigan, NFS's NOIRLab, 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 at NSF's NOIRLab (NOIRLab Prop. ID 2012B-0001; PI: J. Frieman), which is managed 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 MICINN under grants ESP2017-89838, PGC2018-094773, PGC2018-102021, 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 Brazilian Instituto Nacional de Ciencia e Tecnologia (INCT) do e-Universo (CNPq grant 465376/2014-2). This manuscript 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.
Funders | Funder number |
---|---|
Brazilian Instituto Nacional de Ciencia e Tecnologia | |
Center for Cosmology and Astro-Particle Physics at the Ohio StateUniversity | |
Centro Superior de Investigaciones Cientificas | PIE2018-50E099 |
Collaborating Institutions are Argonne National Laboratory | |
Collaborating Institutions in the Dark Energy Survey | |
Fermi Research Alliance, LLC | DE-AC02-07CH11359 |
Institut de Ciencies de l'Espai | |
Mitchell Institute for Fundamental Physics and Astronomy at Texas A&M University | |
Science and Technology Facilities Council of the United Kingdom | |
Zurich | |
National Science Foundation | AST-1816330 |
U.S. Department of Energy | |
University of Illinois at Urbana-Champaign | |
Stanford University | |
Office of Science | |
High Energy Physics | |
Fermilab | |
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 | 2012B-0001, AST-1138766, AST-1536171 |
University of Portsmouth | |
National Centre for Supercomputing Applications | |
Seventh Framework Programme | 1138766, 240672, 1816330, 306478, 291329 |
SLAC National Accelerator Laboratory | |
Higher Education Funding Council for England | |
Engineering Research Centers | |
University of Cambridge | |
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 | |
Ministério da Ciência, Tecnologia e Inovação | |
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 | |
Ministerio de Ciencia e Innovación | SEV-2016-0588, MDM-2015-0509, SEV-2016- 0597, PGC2018-094773, PGC2018-102021, ESP2017-89838 |
Seventh Framework Programme | |
Ludwig-Maximilians-Universität München | |
Instituto Nacional de Ciência e Tecnologia para Excitotoxicidade e Neuroproteção | |
Ministry of Education and Science of Ukraine | |
European Regional Development Fund | |
Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas | |
Institut de Física d'Altes Energies |
Keywords
- Catalogues
- Galaxies: structure
- Methods: observational