Millimeter-wave observations of Euclid Deep Field South using the South Pole Telescope

A data release of temperature maps and catalogs

¹ Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637, USA
² Kavli Institute for Cosmological Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637, USA
³ Department of Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637, USA
⁴ High-Energy Physics Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL 60439, USA
⁵ University Observatory, Faculty of Physics, Ludwig-Maximilians-Universität, Scheinerstr. 1, 81679 Munich, Germany
⁶ Fermi National Accelerator Laboratory, MS209, PO Box 500, Batavia, IL 60510, USA
⁷ School of Physics, University of Melbourne, Parkville, VIC 3010, Australia
⁸ Instituto de Estudios Astrofícos, Facultad de Ingeniería y Ciencias, Universidad Diego Portales, Av. Ejército 441, Santiago, Chile
⁹ Millenium Nucleus for Galaxies
¹⁰ Sorbonne Université, CNRS, UMR 7095, Institut d’Astrophysique de Paris, 98 bis bd Arago, 75014 Paris, France
¹¹ School of Physics and Astronomy, Cardiff University, Cardiff CF24 3YB, UK
¹² Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, 452 Lomita Mall, Stanford, CA 94305, USA
¹³ Department of Physics, Stanford University, 382 Via Pueblo Mall, Stanford, CA 94305, USA
¹⁴ SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
¹⁵ Enrico Fermi Institute, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637, USA
¹⁶ Department of Astronomy, University of Florida, Gainesville, FL 32611, USA
¹⁷ Department of Physics and Astronomy, University of British Columbia, 6225 Agricultural Rd., Vancouver V6T 1Z1, Canada
¹⁸ National Research Council, Herzberg Astronomy and Astrophysics, 5071 West Saanich Rd., Victoria V9E 2E7, Canada
¹⁹ Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, Canada
²⁰ University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637, USA
²¹ Department of Physics, University of California, Berkeley, CA 94720, USA
²² Université Paris-Saclay, Université Paris Cité, CEA, CNRS, AIM, 91191 Gif-sur-Yvette, France
²³ Department of Astronomy, University of Illinois UrbanaChampaign, 1002 West Green Street, Urbana, IL 61801, USA
²⁴ High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801, Japan
²⁵ Wits Centre for Astrophysics, University of the Witwatersrand, 1 Jan Smuts Avenue, 2000 Johannesburg, South Africa
²⁶ Department of Physics, University of Pretoria, Hatfield, Pretoria 0028, South Africa
²⁷ Department of Physics and McGill Space Institute, McGill University, 3600 Rue University, Montreal, Quebec H3A 2T8, Canada
²⁸ Canadian Institute for Advanced Research, CIFAR Program in Gravity and the Extreme Universe, Toronto, ON M5G 1Z8, Canada
²⁹ Joseph Henry Laboratories of Physics, Jadwin Hall, Princeton University, Princeton, NJ 08544, USA
³⁰ Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309, USA
³¹ Department of Physics, University of Illinois Urbana-Champaign, 1110 West Green Street, Urbana, IL 61801, USA
³² Department of Physics and Astronomy, University of California, Los Angeles, CA 90095, USA
³³ Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824, USA
³⁴ Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Portsmouth PO1 3FX, UK
³⁵ Department of Physics & Astronomy, University of California, One Shields Avenue, Davis, CA 95616, USA
³⁶ Universität Innsbruck, Institut für Astro- und Teilchenphysik, Technikerstrasse 25, 6020 Innsbruck, Austria
³⁷ Cosmic Dawn Center (DAWN), Technical University of Denmark, DTU Space, Elektrovej 327, 2800 Kgs Lyngby, Denmark
³⁸ Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK
³⁹ Department of Physics and Astronomy, Northwestern University, 633 Clark St, Evanston, IL 60208, USA
⁴⁰ CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309, USA
⁴¹ Department of Physics, University of Colorado, Boulder, CO 80309, USA
⁴² Department of Physics, Case Western Reserve University, Cleveland, OH 44106, USA
⁴³ Center for AstroPhysical Surveys, National Center for Supercomputing Applications, Urbana, IL 61801, USA
⁴⁴ Dunlap Institute for Astronomy & Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4, Canada
⁴⁵ David A. Dunlap Department of Astronomy & Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4, Canada
⁴⁶ NSF-Simons AI Institute for the Sky (SkAI), 172 E. Chestnut St., Chicago, IL 60611, USA
⁴⁷ Vera C. Rubin Observatory Project Office, 950 N Cherry Ave, Tucson, AZ 85719, USA
⁴⁸ Center for Astrophysics | Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USA
⁴⁹ Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany

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Received: 3 June 2025
Accepted: 14 November 2025

Abstract

Context. The South Pole Telescope third-generation camera (SPT-3G) has observed over 10 000 square degrees of sky at 95, 150, and 220 GHz (3.3, 2.0, 1.4 mm, respectively) and will significantly overlap the ongoing 14 000 square-degree Euclid Wide Survey. The Euclid collaboration recently released Euclid Deep Field South (EDF-S) observations of 23 square degrees at wide field depths in the first quick data release (Q1).

Aims. With the goal of releasing complementary millimeter-wave data and encouraging legacy science, we performed dedicated observations of a 57-square-degree field overlapping the EDF-S.

Methods. The observing time totaled 20 days, and we reached noise depths of 4.3, 3.8, and 13.2 μK-arcmin at 95, 150, and 220 GHz, respectively.

Results. In this work we present the temperature maps and two catalogs constructed from these data. The emissive source catalog contains 601 objects (334 inside EDF-S) with 54% synchrotron-dominated sources and 46% thermal dust emission-dominated sources. The 5σ detection thresholds are 1.7, 2.0, and 6.5 mJy in the three bands. The cluster catalog contains 217 cluster candidates (121 inside EDF-S) with median mass M_500c = 2.12 × 10¹⁴ M_⊙/h₇₀ and median redshift z = 0.70, corresponding to an order-of-magnitude improvement in cluster density over previous tSZ-selected catalogs in this region (3.81 clusters per square degree).

Conclusions. The overlap between SPT and Euclid data will enable a range of multiwavelength studies of the aforementioned source populations. This work serves as the first step toward joint projects between SPT and Euclid and provides a rich dataset containing information on galaxies, clusters, and their environments.