Euclid Quick Data Release (Q1)

X. A census of dwarf galaxies across a range of distances and environments

¹ Universität Innsbruck, Institut für Astro- und Teilchenphysik, Technikerstr. 25/8, 6020 Innsbruck, Austria
² INAF – Osservatorio Astronomico d’Abruzzo, Via Maggini, 64100 Teramo, Italy
³ INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy
⁴ INAF-Osservatorio Astronomico di Capodimonte, Via Moiariello 16, 80131 Napoli, Italy
⁵ Université de Strasbourg, CNRS, Observatoire astronomique de Strasbourg, UMR 7550, 67000 Strasbourg, France
⁶ Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
⁷ David A. Dunlap Department of Astronomy & Astrophysics, University of Toronto, 50 St George Street, Toronto, Ontario M5S 3H4, Canada
⁸ Jodrell Bank Centre for Astrophysics, Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
⁹ Universitäts-Sternwarte München, Fakultät für Physik, Ludwig-Maximilians-Universität München, Scheinerstrasse 1, 81679 München, Germany
¹⁰ Max Planck Institute for Extraterrestrial Physics, Giessenbachstr. 1, 85748 Garching, Germany
¹¹ Instituto de Astrofísica de Canarias, Vía Láctea, 38205 La Laguna, Tenerife, Spain
¹² Universidad de La Laguna, Departamento de Astrofísica, 38206 La Laguna, Tenerife, Spain
¹³ School of Physics & Astronomy, University of Southampton, Highfield Campus, Southampton SO17 1BJ, UK
¹⁴ Kapteyn Astronomical Institute, University of Groningen, PO Box 800, 9700 AV Groningen, The Netherlands
¹⁵ European Space Agency/ESTEC, Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands
¹⁶ European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany
¹⁷ Institute of Physics, Laboratory of Astrophysics, Ecole Polytechnique Fédérale de Lausanne (EPFL), Observatoire de Sauverny, 1290 Versoix, Switzerland
¹⁸ Visiting Fellow, Clare Hall, University of Cambridge, Cambridge, UK
¹⁹ Space physics and astronomy research unit, University of Oulu, Pentti Kaiteran katu 1, FI-90014 Oulu, Finland
²⁰ Université Paris-Saclay, CNRS, Institut d’astrophysique spatiale, 91405 Orsay, France
²¹ ESAC/ESA, Camino Bajo del Castillo, s/n., Urb. Villafranca del Castillo, 28692 Villanueva de la Cañada, Madrid, Spain
²² School of Mathematics and Physics, University of Surrey, Guildford, Surrey GU2 7XH, UK
²³ INAF-Osservatorio Astronomico di Brera, Via Brera 28, 20122 Milano, Italy
²⁴ INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy
²⁵ Université Paris-Saclay, Université Paris Cité, CEA, CNRS, AIM, 91191 Gif-sur-Yvette, France
²⁶ IFPU, Institute for Fundamental Physics of the Universe, Via Beirut 2, 34151 Trieste, Italy
²⁷ INFN, Sezione di Trieste, Via Valerio 2, 34127 Trieste TS, Italy
²⁸ SISSA, International School for Advanced Studies, Via Bonomea 265, 34136 Trieste TS, Italy
²⁹ Dipartimento di Fisica e Astronomia, Università di Bologna, Via Gobetti 93/2, 40129 Bologna, Italy
³⁰ INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy
³¹ INAF-Osservatorio Astronomico di Padova, Via dell’Osservatorio 5, 35122 Padova, Italy
³² Centre National d’Etudes Spatiales – Centre spatial de Toulouse, 18 avenue Edouard Belin, 31401 Toulouse Cedex 9, France
³³ Space Science Data Center, Italian Space Agency, Via del Politecnico snc, 00133 Roma, Italy
³⁴ INAF-Osservatorio Astrofisico di Torino, Via Osservatorio 20, 10025 Pino Torinese ( TO), Italy
³⁵ Dipartimento di Fisica, Università di Genova, Via Dodecaneso 33, 16146 Genova, Italy
³⁶ INFN-Sezione di Genova, Via Dodecaneso 33, 16146 Genova, Italy
³⁷ Department of Physics “E. Pancini”, University Federico II, Via Cinthia 6, 80126 Napoli, Italy
³⁸ Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP, Rua das Estrelas, PT4150-762 Porto, Portugal
³⁹ Faculdade de Ciências da Universidade do Porto, Rua do Campo de Alegre, 4150-007 Porto, Portugal
⁴⁰ Dipartimento di Fisica, Università degli Studi di Torino, Via P. Giuria 1, 10125 Torino, Italy
⁴¹ INFN-Sezione di Torino, Via P. Giuria 1, 10125 Torino, Italy
⁴² Institute Lorentz, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands
⁴³ Leiden Observatory, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
⁴⁴ INAF-IASF Milano, Via Alfonso Corti 12, 20133 Milano, Italy
⁴⁵ Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Avenida Complutense 40, 28040 Madrid, Spain
⁴⁶ Port d’Informació Científica, Campus UAB, C. Albareda s/n, 08193 Bellaterra (Barcelona), Spain
⁴⁷ Institute for Theoretical Particle Physics and Cosmology (TTK), RWTH Aachen University, 52056 Aachen, Germany
⁴⁸ INAF-Osservatorio Astronomico di Roma, Via Frascati 33, 00078 Monteporzio Catone, Italy
⁴⁹ INFN section of Naples, Via Cinthia 6, 80126 Napoli, Italy
⁵⁰ Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822, USA
⁵¹ Dipartimento di Fisica e Astronomia “Augusto Righi” – Alma Mater Studiorum Università di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy
⁵² Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK
⁵³ European Space Agency/ESRIN, Largo Galileo Galilei 1, 00044 Frascati, Roma, Italy
⁵⁴ Université Claude Bernard Lyon 1, CNRS/IN2P3, IP2I Lyon, UMR 5822, Villeurbanne F-69100, France
⁵⁵ Institut de Ciències del Cosmos (ICCUB), Universitat de Barcelona (IEEC-UB), Martí i Franquès 1, 08028 Barcelona, Spain
⁵⁶ Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig de Lluís Companys 23, 08010 Barcelona, Spain
⁵⁷ UCB Lyon 1, CNRS/IN2P3, IUF, IP2I Lyon, 4 rue Enrico Fermi, 69622 Villeurbanne, France
⁵⁸ Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT, UK
⁵⁹ Departamento de Física, Faculdade de Ciências, Universidade de Lisboa, Edifício C8 Campo Grande, PT1749-016 Lisboa, Portugal
⁶⁰ Instituto de Astrofísica e Ciências do Espaço, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
⁶¹ Department of Astronomy, University of Geneva, ch. d’Ecogia 16, 1290 Versoix, Switzerland
⁶² INAF-Istituto di Astrofisica e Planetologia Spaziali, Via del Fosso del Cavaliere, 100, 00100 Roma, Italy
⁶³ INFN-Padova, Via Marzolo 8, 35131 Padova, Italy
⁶⁴ Aix-Marseille Université, CNRS/IN2P3, CPPM, Marseille, France
⁶⁵ Institut d’Estudis Espacials de Catalunya (IEEC), Edifici RDIT, Campus UPC, 08860 Castelldefels, Barcelona, Spain
⁶⁶ Institute of Space Sciences (ICE, CSIC), Campus UAB, Carrer de Can Magrans, s/n, 08193 Barcelona, Spain
⁶⁷ School of Physics, HH Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UK
⁶⁸ NRC Herzberg, 5071 West Saanich Rd, Victoria, BC V9E 2E7, Canada
⁶⁹ Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, 0315 Oslo, Norway
⁷⁰ Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
⁷¹ Felix Hormuth Engineering, Goethestr. 17, 69181 Leimen, Germany
⁷² Technical University of Denmark, Elektrovej 327, 2800 Kgs. Lyngby, Denmark
⁷³ Cosmic Dawn Center (DAWN), Denmark
⁷⁴ Institut d’Astrophysique de Paris, UMR 7095, CNRS, and Sorbonne Université, 98 bis boulevard Arago, 75014 Paris, France
⁷⁵ Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
⁷⁶ NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
⁷⁷ Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK
⁷⁸ Department of Physics and Helsinki Institute of Physics, Gustaf Hällströmin katu 2, 00014 University of Helsinki, Finland
⁷⁹ Université de Genève, Département de Physique Théorique and Centre for Astroparticle Physics, 24 quai Ernest-Ansermet, CH-1211 Genève 4, Switzerland
⁸⁰ Department of Physics, P.O. Box 64, 00014 University of Helsinki, Finland
⁸¹ Helsinki Institute of Physics, Gustaf Hällströmin katu 2, University of Helsinki, Helsinki, Finland
⁸² Centre de Calcul de l’IN2P3/CNRS, 21 avenue Pierre de Coubertin, 69627 Villeurbanne Cedex, France
⁸³ Laboratoire d’etude de l’Univers et des phenomenes eXtremes, Observatoire de Paris, Université PSL, Sorbonne Université, CNRS, 92190 Meudon, France
⁸⁴ Aix-Marseille Université, CNRS, CNES, LAM, Marseille, France
⁸⁵ SKA Observatory, Jodrell Bank, Lower Withington, Macclesfield, Cheshire SK11 9FT, UK
⁸⁶ Dipartimento di Fisica “Aldo Pontremoli”, Università degli Studi di Milano, Via Celoria 16, 20133 Milano, Italy
⁸⁷ INFN-Sezione di Milano, Via Celoria 16, 20133 Milano, Italy
⁸⁸ University of Applied Sciences and Arts of Northwestern Switzerland, School of Engineering, 5210 Windisch, Switzerland
⁸⁹ Universität Bonn, Argelander-Institut für Astronomie, Auf dem Hügel 71, 53121 Bonn, Germany
⁹⁰ INFN-Sezione di Roma, Piazzale Aldo Moro, 2 – c/o Dipartimento di Fisica, Edificio G. Marconi, 00185 Roma, Italy
⁹¹ Dipartimento di Fisica e Astronomia “Augusto Righi” – Alma Mater Studiorum Università di Bologna, Via Piero Gobetti 93/2, 40129 Bologna, Italy
⁹² Department of Physics, Institute for Computational Cosmology, Durham University, South Road, Durham DH1 3LE, UK
⁹³ Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, Bd de l’Observatoire, CS 34229, 06304 Nice cedex 4, France
⁹⁴ Université Paris Cité, CNRS, Astroparticule et Cosmologie, 75013 Paris, France
⁹⁵ CNRS-UCB International Research Laboratory, Centre Pierre Binétruy, IRL2007, CPB-IN2P3, Berkeley, USA
⁹⁶ Institut d’Astrophysique de Paris, 98bis Boulevard Arago, 75014 Paris, France
⁹⁷ Aurora Technology for European Space Agency (ESA), Camino bajo del Castillo, s/n, Urbanizacion Villafranca del Castillo, Villanueva de la Cañada, 28692 Madrid, Spain
⁹⁸ Institut de Física d’Altes Energies (IFAE), The Barcelona Institute of Science and Technology, Campus UAB, 08193 Bellaterra (Barcelona), Spain
⁹⁹ School of Mathematics, Statistics and Physics, Newcastle University, Herschel Building, Newcastle-upon-Tyne, NE1 7RU, UK
¹⁰⁰ DARK, Niels Bohr Institute, University of Copenhagen, Jagtvej 155, 2200 Copenhagen, Denmark
¹⁰¹ Waterloo Centre for Astrophysics, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
¹⁰² Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
¹⁰³ Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2L 2Y5, Canada
¹⁰⁴ Institute of Space Science, Str. Atomistilor, nr. 409M°agurele, Ilfov 077125, Romania
¹⁰⁵ Consejo Superior de Investigaciones Cientificas, Calle Serrano 117, 28006 Madrid, Spain
¹⁰⁶ Dipartimento di Fisica e Astronomia “G. Galilei”, Università di Padova, Via Marzolo 8, 35131 Padova, Italy
¹⁰⁷ Caltech/IPAC, 1200 E. California Blvd., Pasadena, CA 91125, USA
¹⁰⁸ Institut für Theoretische Physik, University of Heidelberg, Philosophenweg 16, 69120 Heidelberg, Germany
¹⁰⁹ Institut de Recherche en Astrophysique et Planétologie (IRAP), Université de Toulouse, CNRS, UPS, CNES, 14 Av. Edouard Belin, 31400 Toulouse, France
¹¹⁰ Université St Joseph; Faculty of Sciences, Beirut, Lebanon
¹¹¹ Departamento de Física, FCFM, Universidad de Chile, Blanco Encalada 2008, Santiago, Chile
¹¹² Satlantis, University Science Park, Sede Bld 48940, Leioa-Bilbao, Spain
¹¹³ Centre for Electronic Imaging, Open University, Walton Hall, Milton Keynes, MK7 6AA, UK
¹¹⁴ Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125, USA
¹¹⁵ Instituto de Astrofísica e Ciências do Espaço, Faculdade de Ciências, Universidade de Lisboa, Tapada da Ajuda, 1349-018 Lisboa, Portugal
¹¹⁶ Cosmic Dawn Center (DAWN)
¹¹⁷ Niels Bohr Institute, University of Copenhagen, Jagtvej 128, 2200 Copenhagen, Denmark
¹¹⁸ Universidad Politécnica de Cartagena, Departamento de Electrónica y Tecnología de Computadoras, Plaza del Hospital 1, 30202 Cartagena, Spain
¹¹⁹ INFN-Bologna, Via Irnerio 46, 40126 Bologna, Italy
¹²⁰ Dipartimento di Fisica e Scienze della Terra, Università degli Studi di Ferrara, Via Giuseppe Saragat 1, 44122 Ferrara, Italy
¹²¹ Istituto Nazionale di Fisica Nucleare, Sezione di Ferrara, Via Giuseppe Saragat 1, 44122 Ferrara, Italy
¹²² INAF, Istituto di Radioastronomia, Via Piero Gobetti 101, 40129 Bologna, Italy
¹²³ Department of Physics, Oxford University, Keble Road, Oxford OX1 3RH, UK
¹²⁴ Instituto de Astrofísica de Canarias (IAC); Departamento de Astrofísica, Universidad de La Laguna (ULL), 38200 La Laguna, Tenerife, Spain
¹²⁵ Université PSL, Observatoire de Paris, Sorbonne Université, CNRS, LERMA, 75014 Paris, France
¹²⁶ Université Paris-Cité, 5 Rue Thomas Mann, 75013 Paris, France
¹²⁷ ICL, Junia, Université Catholique de Lille, LITL, 59000 Lille, France
¹²⁸ ICSC – Centro Nazionale di Ricerca in High Performance Computing, Big Data e Quantum Computing, Via Magnanelli 2, Bologna, Italy
¹²⁹ Instituto de Física Teórica UAM-CSIC, Campus de Cantoblanco, 28049 Madrid, Spain
¹³⁰ CERCA/ISO, Department of Physics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
¹³¹ Technical University of Munich, TUM School of Natural Sciences, Physics Department, James-Franck-Str. 1, 85748 Garching, Germany
¹³² Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85748 Garching, Germany
¹³³ Laboratoire Univers et Théorie, Observatoire de Paris, Université PSL, Université Paris Cité, CNRS, 92190 Meudon, France
¹³⁴ Departamento de Física Fundamental. Universidad de Salamanca, Plaza de la Merced s/n, 37008 Salamanca, Spain
¹³⁵ Dipartimento di Fisica – Sezione di Astronomia, Università di Trieste, Via Tiepolo 11, 34131 Trieste, Italy
¹³⁶ California Institute of Technology, 1200 E California Blvd, Pasadena, CA 91125, USA
¹³⁷ Departamento de Física Teórica, Atómica y Óptica, Universidad de Valladolid, 47011 Valladolid, Spain
¹³⁸ Laboratory for Disruptive Interdisciplinary Science (LaDIS), Universidad de Valladolid, 47011 Valladolid, Spain
¹³⁹ Department of Physics & Astronomy, University of California Irvine, Irvine CA 92697, USA
¹⁴⁰ Department of Mathematics and Physics E. De Giorgi, University of Salento, Via per Arnesano, CP-I93, 73100 Lecce, Italy
¹⁴¹ INFN, Sezione di Lecce, Via per Arnesano, CP-193, 73100 Lecce, Italy
¹⁴² INAF-Sezione di Lecce, c/o Dipartimento Matematica e Fisica, Via per Arnesano, 73100 Lecce, Italy
¹⁴³ Departamento Física Aplicada, Universidad Politecnica de Cartagena, Campus Muralla del Mar, 30202 Cartagena, Murcia, Spain
¹⁴⁴ Instituto de Física de Cantabria, Edificio Juan Jordá, Avenida de los Castros, 39005 Santander, Spain
¹⁴⁵ Observatorio Nacional, Rua General Jose Cristino, 77-Bairro Imperial de Sao Cristovao, Rio de Janeiro, 20921-400, Brazil
¹⁴⁶ Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth PO1 3FX, UK
¹⁴⁷ Department of Computer Science, Aalto University, PO Box 15400 Espoo FI-00 076, Finland
¹⁴⁸ Instituto de Astrofísica de Canarias; Departamento de Astrofísica de la Universidad de La Laguna, c/ Via Lactea s/n, Avda. Francisco Sanchez, La Laguna, 38200, Spain
¹⁴⁹ Ruhr University Bochum, Faculty of Physics and Astronomy, Astronomical Institute (AIRUB), German Centre for Cosmological Lensing (GCCL), 44780 Bochum, Germany
¹⁵⁰ Department of Physics and Astronomy, Vesilinnantie 5, 20014 University of Turku, Finland
¹⁵¹ Serco for European Space Agency (ESA), Camino bajo del Castillo, s/n, Urbanizacion Villafranca del Castillo, Villanueva de la Cañada, 28692 Madrid, Spain
¹⁵² ARC Centre of Excellence for Dark Matter Particle Physics, Melbourne, Australia
¹⁵³ Centre for Astrophysics & Supercomputing, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
¹⁵⁴ Department of Physics and Astronomy, University of the Western Cape, Bellville, Cape Town, 7535, South Africa
¹⁵⁵ DAMTP, Centre for Mathematical Sciences, Wilberforce Road, Cambridge CB3 0WA, UK
¹⁵⁶ Kavli Institute for Cosmology Cambridge, Madingley Road, Cambridge CB3 0HA, UK
¹⁵⁷ Department of Astrophysics, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
¹⁵⁸ Department of Physics, Centre for Extragalactic Astronomy, Durham University, South Road, Durham DH1 3LE, UK
¹⁵⁹ IRFU, CEA, Université Paris-Saclay, 91191 Gif-sur-Yvette Cedex, France
¹⁶⁰ Univ. Grenoble Alpes, CNRS, Grenoble INP, LPSC-IN2P3, 53, Avenue des Martyrs, 38000 Grenoble, France
¹⁶¹ INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy
¹⁶² Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 2, 00185 Roma, Italy
¹⁶³ Centro de Astrofísica da Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal
¹⁶⁴ HE Space for European Space Agency (ESA), Camino bajo del Castillo, s/n, Urbanizacion Villafranca del Castillo, Villanueva de la Cañada, 28692 Madrid, Spain
¹⁶⁵ Theoretical astrophysics, Department of Physics and Astronomy, Uppsala University, Box 515, 751 20 Uppsala, Sweden
¹⁶⁶ Mathematical Institute, University of Leiden, Einsteinweg 55, 2333 CA Leiden, The Netherlands
¹⁶⁷ Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544, USA
¹⁶⁸ Center for Computational Astrophysics, Flatiron Institute, 162 5th Avenue, 10010 New York, NY, USA
¹⁶⁹ Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1, Canada

^★ Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Received: 14 March 2025
Accepted: 31 July 2025

Abstract

The Euclid Q1 fields were selected for calibration purposes in cosmology and are therefore relatively devoid of nearby galaxies. However, this is precisely what makes them interesting fields in which to search for dwarf galaxies in local density environments. We took advantage of the unprecedented depth, spatial resolution, and field of view of the Euclid Quick Release (Q1) to build a census of dwarf galaxies in these regions. We have identified dwarf galaxies in a representative sample of 25 contiguous tiles in the Euclid Deep Field North (EDF-N) covering an area of 14.25 deg². The dwarf galaxy candidates were identified using a semi-automatic detection method based on properties measured by the Euclid pipeline and released as part of the catalogue produced by the MERge Processing Function (MER PF) pipeline. A selection cut in surface brightness and magnitude was used to produce an initial dwarf candidate catalogue, and this was followed by a cut in morphology (removing background spirals) and I_E − H_E colour (removing red ellipticals). This catalogue was then visually classified to produce a final sample of dwarf candidates, including their morphology, number of nuclei, globular cluster (GC) richness, and presence of a blue compact centre. We identified 2674 dwarf candidates, corresponding to 188 dwarfs per square degree. The visual classification of the dwarfs reveals a slightly uneven morphological mix of 58% ellipticals and 42% irregulars, with very few potentially GC-rich (1.0%) and nucleated (4.0%) candidates but a noticeable fraction (6.9%) of dwarfs with blue compact centres. The distance distribution of 388 (15%) of the dwarf candidates with spectroscopic redshifts peaks at about 400 Mpc. Their stellar mass distribution confirms that our selection effectively identifies dwarfs while minimising contamination. The most prominent dwarf overdensities are dominated by dwarf ellipticals, while dwarf irregulars are more evenly distributed across the field of view. This work highlights Euclid’s remarkable ability to detect and characterise dwarf galaxies across diverse masses, distances, and environments.