UNIONS: The Ultraviolet Near-infrared Optical Northern Survey

Abstract The Ultraviolet Near-Infrared Optical Northern Survey (UNIONS) is a “collaboration of collaborations” that is using the Canada–France–Hawai’i Telescope, the Pan-STARRS telescopes, and the Subaru Observatory to obtain ugriz images of a core survey region of 6250 deg 2 of the northern sky. The 10 σ point source depth of the data, as measured within a 2″ diameter aperture, are [ u , g , r , i , z ] = [23.7, 24.5, 24.2, 23.8, 23.3] in AB magnitudes. UNIONS is addressing some of the most fundamental questions in astronomy, including the properties of dark matter, the growth of structure in the Universe from the very smallest galaxies to large-scale structure, and the assembly of the Milky Way. It is set to become a major ground-based legacy survey for the northern hemisphere for the next decade, and it provides an essential northern complement to the static-sky science of the Vera C. Rubin Observatory’s Legacy Survey of Space and Time. UNIONS supports the core science mission of the Euclid space mission by providing the data necessary in the northern hemisphere for the calibration of the wavelength dependence of the Euclid point-spread function and derivation of photometric redshifts in the North Galactic Cap. This region contains the highest quality sky for Euclid, with low backgrounds from the zodiacal light, stellar density, extinction, and emission from Galactic cirrus. Here, we describe the UNIONS survey components, science goals, data products, and the current status of the overall program.

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Publication Details

Journal
The Astronomical Journal
Published
2025-11-12
DOI
https://doi.org/10.3847/1538-3881/ae03ab
Citations
9
Primary Topic
Photocathodes and Microchannel Plates
Type
article
Field-Weighted Citation Impact
6.07

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article

UNIONS: The Ultraviolet Near-infrared Optical Northern Survey

Lucie Baumont, E. A. Magnier, Hisanori Furusawa, G. E. Medina et al.
9 citations
The Astronomical Journal
Photocathodes and Microchannel Plates
6.07
article

UNIONS: The Ultraviolet Near-infrared Optical Northern Survey

Lucie Baumont, E. A. Magnier, Hisanori Furusawa, G. E. Medina, Jean‐Luc Starck, Masafusa Onoue, M. Schultheis, Julio F. Navarro, Federico Sestito, Charlie T. Mpetha, F. Durret, Thomas de Boer, Gregory S. H. Paek, V. Hénault-Brunet, Kim A. Venn, Michael J. Hudson, Salvatore Taibi, Oliver Müller, T. Erben, Masafumi Niwano, Chien-Cheng Lin, Pierre–Alain Duc, S. Fabbro, Ken Osato, Yoshihisa Suzuki, TianFang Zhang, Else Starkenburg, Tohru Nagao, Kohei Hayashi, Satoshi Miyazaki, T.I Liaudat, H. Hildebrandt, Hisakazu Uchiyama, Yoshiki Toba, F. Hammer, Christopher Storfer, Yuichi Harikane, Alan W. McConnachie, D. Valls‐Gabaud, Sara L. Ellison, Patrick Côté, David R. Patton, Rodrigo Ibata, Nick Heesters, Yoshiki Matsuoka, Itsna K. Fitriana, Tomotsugu Goto, L.W.K Goh, Hironao Miyatake, E. Le Floc’h, C. Daley, Simon E. T. Smith, Anna Wittje, Nobuhiro Okabe, Yoshinobu Fudamoto, Kohei Ichikawa, R. G. Carlberg, Connor Stone, Laura C. Parker, K. C. Chambers, M. Kilbinger, R. Gavazzi, Junko Furusawa, Jean‐Charles Cuillandre, Guillaume F. Thomas, Yuxing Zhong, O. Boulade, A. Ellien, Masamune Oguri, Hua Gao, R. J. Wainscoat, Qinxun Li, Axel Guinot, Nicolas F. Martin, P. B. Kuzma, Scott Wilkinson, Fabian Hervas Peters, Sacha Guerrini, Itsuki Ogami, Leonardo Ferreira, Rubén Sánchez-Janssen, Ludovic Van Waerbeke, Y. Mellier, S. Prunet, T. Yoshida, Manuel Bayer, David Chemaly
article en
9 citations

Abstract

Abstract The Ultraviolet Near-Infrared Optical Northern Survey (UNIONS) is a “collaboration of collaborations” that is using the Canada–France–Hawai’i Telescope, the Pan-STARRS telescopes, and the Subaru Observatory to obtain ugriz images of a core survey region of 6250 deg 2 of the northern sky. The 10 σ point source depth of the data, as measured within a 2″ diameter aperture, are [ u , g , r , i , z ] = [23.7, 24.5, 24.2, 23.8, 23.3] in AB magnitudes. UNIONS is addressing some of the most fundamental questions in astronomy, including the properties of dark matter, the growth of structure in the Universe from the very smallest galaxies to large-scale structure, and the assembly of the Milky Way. It is set to become a major ground-based legacy survey for the northern hemisphere for the next decade, and it provides an essential northern complement to the static-sky science of the Vera C. Rubin Observatory’s Legacy Survey of Space and Time. UNIONS supports the core science mission of the Euclid space mission by providing the data necessary in the northern hemisphere for the calibration of the wavelength dependence of the Euclid point-spread function and derivation of photometric redshifts in the North Galactic Cap. This region contains the highest quality sky for Euclid, with low backgrounds from the zodiacal light, stellar density, extinction, and emission from Galactic cirrus. Here, we describe the UNIONS survey components, science goals, data products, and the current status of the overall program.

The Astronomical JournalVol. 170(6)
National Science Foundation, Smithsonian Institution, National Aeronautics and Space Administration, Gordon and Betty Moore Foundation, Princeton University, Johns Hopkins University, Canadian Foundation for AIDS Research, Canarie, University of Hawai'i, Space Telescope Science Institute, European Space Agency, European Commission, Queen's University Belfast, Durham University, Deutsche Forschungsgemeinschaft, Ministry of Education, Culture, Sports, Science and Technology, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Academia Sinica, Cabinet Office, Government of Japan, Centre National d’Etudes Spatiales, Nederlandse Organisatie voor Wetenschappelijk Onderzoek, Queen's University, Nuclear Safety and Security Commission, Max-Planck-Gesellschaft, Centre National de la Recherche Scientifique, National Central University, National Astronomical Observatory of Japan, High Energy Accelerator Research Organization, Eötvös Loránd Tudományegyetem, Max-Planck-Institut für Astronomie, Toray Science Foundation, Smithsonian Astrophysical Observatory, Science Mission Directorate, HORIZON EUROPE Framework Programme, Canadian Space Agency, Natural Sciences and Engineering Research Council of Canada, Japan Society for the Promotion of Science, Japan Science and Technology Agency, Planetary Science Division, Los Alamos National Laboratory
Openalex Percentile: Top 4%
Photocathodes and Microchannel Plates
6.07
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