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Transfer learning for galaxy morphology from one survey to another

Sánchez, HD; Huertas-Company, M; Bernardi, M; Kaviraj, S; Fischer, JL; Abbott, TMC; Abdalla, FB; ... Zuntz, J; + view all (2019) Transfer learning for galaxy morphology from one survey to another. Monthly Notices of the Royal Astronomical Society , 484 (1) pp. 93-100. 10.1093/mnras/sty3497. Green open access

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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.

Type: Article
Title: Transfer learning for galaxy morphology from one survey to another
Open access status: An open access version is available from UCL Discovery
DOI: 10.1093/mnras/sty3497
Publisher version: https://doi.org/10.1093/mnras/sty3497
Language: English
Additional information: This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions.
Keywords: methods: observational, methods: photometric, surveys, galaxies: structure
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy
URI: https://discovery-pp.ucl.ac.uk/id/eprint/10052605
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