Abstract
Deep learning (DL) algorithms for morphological classification of galaxies have proven very successful, mimicking (or even improving) visual classifications. However, these algorithms rely on large training samples of labelled galaxies (typically thousands of them). A key question for using DL classifications in future Big Data surveys is how much of the knowledge acquired from an existing survey can be exported to a new data set, i.e. if the features learned by the machines are meaningful for different data. We test the performance of DL models, trained with Sloan Digital Sky Survey (SDSS) data, on Dark Energy Survey (DES) using images for a sample of ~5000 galaxies with a similar redshift distribution to SDSS. Applying the models directly to DES data provides a reasonable global accuracy (∼90 per cent), but small completeness and purity values. A fast domain adaptation step, consisting of a further training with a small DES sample of galaxies (∼500-300), is enough for obtaining an accuracy >95 per cent and a significant improvement in the completeness and purity values. This demonstrates that, once trained with a particular data set, machines can quickly adapt to new instrument characteristics (e.g. PSF, seeing, depth), reducing by almost one order of magnitude the necessary training sample for morphological classification. Redshift evolution effects or significant depth differences are not taken into account in this study.
Original language | English |
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Pages (from-to) | 93-100 |
Number of pages | 8 |
Journal | Monthly Notices of the Royal Astronomical Society |
Volume | 484 |
Issue number | 1 |
DOIs | |
State | Published - Mar 21 2019 |
Bibliographical note
Publisher Copyright:© 2018 The Author(s).
Funding
The authors would like to thank the anonymous referee for the useful comments which helped to improve the content of the paper. This work was supported in part by NSF AST-1816330. Funding for the DES Projects has been provided by the DOE and NSF(USA), MEC/MICINN/MINECO(Spain), STFC(UK), HEFCE(UK). NCSA(UIUC), KICP(U. Chicago), CCAPP(Ohio State), MIFPA(Texas A&M), CNPQ, FAPERJ, FINEP (Brazil), DFG(Germany), and the Collaborating Institutions in the Dark Energy Survey. The Collaborating Institutions are Argonne Lab, UC Santa Cruz, University of Cambridge, CIEMAT-Madrid, University of Chicago, University College London, DES-Brazil Consortium, University of Edinburgh, ETH Zürich, Fermilab, University of Illinois, ICE (IEEC-CSIC), IFAE Barcelona, Lawrence Berkeley Lab, LMU München and the associated Excellence Cluster Universe, University of Michigan, NOAO, University of Nottingham, Ohio State University, University of Pennsylvania, University of Portsmouth, SLAC National Lab, Stanford University, 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 NSF 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 (CAAS-TRO), through project number CE110001020, and the Brazilian Instituto Nacional de Ciência e Tecnologia (INCT) e-Universe (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. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a nonexclusive, 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.
Funders | Funder number |
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Brazilian Instituto Nacional de Ciência e Tecnologia | |
CAAS-TRO | CE110001020 |
Fermi Research Alliance, LLC | DE-AC02-07CH11359 |
INCT | |
National Science Foundation | SEV-2016-0588, SEV-2016-0597, ESP2015-66861, 1138766, AST-1138766, MDM-2015-0509, 1816330, FPA2015-68048, AST-1536171, AYA2015-71825, AST-1816330 |
U.S. Department of Energy | |
Office of Science | |
High Energy Physics | |
Seventh Framework Programme | 240672, 306478, 291329 |
Engineering Research Centers | |
Science and Technology Facilities Council | ST/N000668/1 |
European Commission | |
European Research Council | |
Australian Research Council | |
Generalitat de Catalunya | |
Ministerio de Economía y Competitividad | |
Conselho Nacional de Desenvolvimento Científico e Tecnológico | 465376/2014-2 |
Ministerio de Ciencia e Innovación | |
European Regional Development Fund |
Keywords
- Galaxies: structure
- Methods: observational
- Methods: photometric
- Surveys