Galaxy Zoo: Cosmic Dawn–morphological classifications for over 41 000 galaxies in the Euclid Deep Field North from the Hawaii Two-0 Cosmic Dawn survey

ABSTRACT We present morphological classifications of over 41 000 galaxies out to $z_{\rm phot}\sim 2.5$ across 6 deg2 of the Euclid Deep Field North (EDFN) from the Hawaii Twenty Square Degree (H20) survey, a part of the wider Cosmic Dawn survey. Galaxy Zoo citizen scientists play a crucial role in the examination of large astronomical data sets through crowdsourced data mining of extragalactic imaging. This iteration, Galaxy Zoo: Cosmic Dawn (GZCD), saw tens of thousands of volunteers and the deep learning foundation model Zoobot collectively classify objects in ultra-deep multiband Hyper Suprime-Cam (HSC) imaging down to a depth of $m_{\mathrm{ HSC}-i} = 21.5$. Here, we present the details and general analysis of this iteration, including the use of Zoobot in an active learning cycle to improve both model performance and volunteer experience, as well as the discovery of 51 new gravitational lenses in the EDFN. We also announce the public data release of the classifications for over 45 000 subjects, including more than 41 000 galaxies (median $z_{\rm phot}$ of $0.42\pm 0.23$), along with their associated image cut-outs. This data set provides a valuable opportunity for follow-up imaging of objects in the EDFN as well as acting as a truth set for training deep learning models for application to ground-based surveys like that of the Ultraviolet Near-Infrared Optical Northern Survey (UNIONS) collaboration and the newly operational Vera C. Rubin Observatory.

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Publication Details

Journal
Monthly Notices of the Royal Astronomical Society
Published
2025-12-19
DOI
https://doi.org/10.1093/mnras/staf2250
Citations
1
Primary Topic
Galaxies: Formation, Evolution, Phenomena
Type
article
Field-Weighted Citation Impact
1.15

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article

Galaxy Zoo: Cosmic Dawn–morphological classifications for over 41 000 galaxies in the Euclid Deep Field North from the Hawaii Two-0 Cosmic Dawn survey

L. Fortson, James F. Pearson, H. J. McCracken, Nagisa Oi et al.
1 citations
Monthly Notices of the Royal Astronomical Society
Galaxies: Formation, Evolution, Phenomena
1.15
article

Galaxy Zoo: Cosmic Dawn–morphological classifications for over 41 000 galaxies in the Euclid Deep Field North from the Hawaii Two-0 Cosmic Dawn survey

L. Fortson, James F. Pearson, H. J. McCracken, Nagisa Oi, Tomotsugu Goto, Sandor Kruk, Matthew A. Malkan, Brooke Simmons, Stephen Serjeant, H. J. Dickinson, L. Zalesky, William Pearson, István Szapudi, W. Turner, Mike Walmsley, K. Masters, Nima Chartab, D. B. Sanders, John R Weaver, Sune Toft, Chris Lintott, Conor McPartland, Bahram Mobasher, Noah East, R J Smethurst
article en
1 citations

Abstract

ABSTRACT We present morphological classifications of over 41 000 galaxies out to $z_{\rm phot}\sim 2.5$ across 6 deg2 of the Euclid Deep Field North (EDFN) from the Hawaii Twenty Square Degree (H20) survey, a part of the wider Cosmic Dawn survey. Galaxy Zoo citizen scientists play a crucial role in the examination of large astronomical data sets through crowdsourced data mining of extragalactic imaging. This iteration, Galaxy Zoo: Cosmic Dawn (GZCD), saw tens of thousands of volunteers and the deep learning foundation model Zoobot collectively classify objects in ultra-deep multiband Hyper Suprime-Cam (HSC) imaging down to a depth of $m_{\mathrm{ HSC}-i} = 21.5$. Here, we present the details and general analysis of this iteration, including the use of Zoobot in an active learning cycle to improve both model performance and volunteer experience, as well as the discovery of 51 new gravitational lenses in the EDFN. We also announce the public data release of the classifications for over 45 000 subjects, including more than 41 000 galaxies (median $z_{\rm phot}$ of $0.42\pm 0.23$), along with their associated image cut-outs. This data set provides a valuable opportunity for follow-up imaging of objects in the EDFN as well as acting as a truth set for training deep learning models for application to ground-based surveys like that of the Ultraviolet Near-Infrared Optical Northern Survey (UNIONS) collaboration and the newly operational Vera C. Rubin Observatory.

Monthly Notices of the Royal Astronomical SocietyVol. 546(3)
University of California, Riverside (US), California Institute of Technology (US), University of Copenhagen (DK), Centre National de la Recherche Scientifique (FR), University of Minnesota (US), University of Hawaii System (US), Haverford College (US), Hokkaido Information University (JP), University of California, Los Angeles (US), The Open University (GB), National Tsing Hua University (TW), Institut d'Astrophysique de Paris (FR), European Space Agency (FR), Sorbonne Université (FR), University of Oxford (GB), European Space Astronomy Centre (ES), Canadian Institute for Theoretical Astrophysics (CA), Institute of Astronomy (RU), Infrared Processing and Analysis Center (US), University of Warsaw (PL), The Ohio State University (US), Massachusetts Institute of Technology (US), Lancaster University (GB)
National Science Foundation, National Aeronautics and Space Administration, Princeton University, Strong, European Commission, National Research Foundation, Danmarks Grundforskningsfond, University of Toronto, Nuclear Safety and Security Commission, National Science and Technology Council
Openalex Percentile: Top 14%
Galaxies: Formation, Evolution, Phenomena
1.15
DOIOpen Access PDFOpenAlex
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