Euclid Quick Data Release (Q1)

XVIII. First Euclid statistical study of the active galactic nuclei contribution fraction

¹ SRON Netherlands Institute for Space Research, Landleven 12, 9747, AD, Groningen, The Netherlands
² Kapteyn Astronomical Institute, University of Groningen, PO Box 800, 9700 AV, Groningen, The Netherlands
³ Instituto de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México, A.P. 72-3, 58089 Morelia, Mexico
⁴ Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP, Rua das Estrelas, PT4150-762 Porto, Portugal
⁵ DTx – Digital Transformation CoLAB, Building 1, Azurém Campus, University of Minho, 4800-058 Guimarães, Portugal
⁶ School of Physics, HH Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UK
⁷ Department of Mathematics and Physics, Roma Tre University, Via della Vasca Navale 84, 00146 Rome, Italy
⁸ INAF-Osservatorio Astronomico di Roma, Via Frascati 33, 00078 Monteporzio Catone, Italy
⁹ Department of Physical Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
¹⁰ National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
¹¹ Academia Sinica Institute of Astronomy and Astrophysics (ASIAA), 11F of ASMAB, No. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan
¹² Institute of Space Sciences (ICE, CSIC), Campus UAB, Carrer de Can Magrans, s/n, 08193 Barcelona, Spain
¹³ Institut d’Estudis Espacials de Catalunya (IEEC), Edifici RDIT, Campus UPC, 08860 Castelldefels, Barcelona, Spain
¹⁴ Max Planck Institute for Extraterrestrial Physics, Giessenbachstr. 1, 85748 Garching, Germany
¹⁵ Instituto de Astrofísica de Canarias, Vía Láctea, 38205 La Laguna, Tenerife, Spain
¹⁶ Universidad de La Laguna, Departamento de Astrofísica, 38206 La Laguna, Tenerife, Spain
¹⁷ Instituto de Astrofísica de Canarias (IAC); Departamento de Astrofísica, Universidad de La Laguna (ULL), 38200 La Laguna, Tenerife, Spain
¹⁸ School of Physics & Astronomy, University of Southampton, Highfield Campus, Southampton SO17 1BJ, UK
¹⁹ INAF-Istituto di Astrofisica e Planetologia Spaziali, Via del Fosso del Cavaliere, 100, 00100 Roma, Italy
²⁰ Leiden Observatory, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
²¹ Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK
²² Université Paris-Saclay, CNRS, Institut d’astrophysique spatiale, 91405 Orsay, France
²³ ESAC/ESA, Camino Bajo del Castillo, s/n., Urb. Villafranca del Castillo, 28692 Villanueva de la Cañada, Madrid, Spain
²⁴ School of Mathematics and Physics, University of Surrey, Guildford, Surrey GU2 7XH, UK
²⁵ INAF-Osservatorio Astronomico di Brera, Via Brera 28, 20122 Milano, Italy
²⁶ INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy
²⁷ Université Paris-Saclay, Université Paris Cité, CEA, CNRS, AIM, 91191 Gif-sur-Yvette, France
²⁸ IFPU, Institute for Fundamental Physics of the Universe, Via Beirut 2, 34151 Trieste, Italy
²⁹ INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy
³⁰ INFN, Sezione di Trieste, Via Valerio 2, 34127 Trieste TS, Italy
³¹ SISSA, International School for Advanced Studies, Via Bonomea 265, 34136 Trieste, TS, Italy
³² Dipartimento di Fisica e Astronomia, Università di Bologna, Via Gobetti 93/2, 40129 Bologna, Italy
³³ INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy
³⁴ INAF-Osservatorio Astronomico di Padova, Via dell’Osservatorio 5, 35122 Padova, Italy
³⁵ Space Science Data Center, Italian Space Agency, Via del Politecnico snc, 00133 Roma, Italy
³⁶ INAF-Osservatorio Astrofisico di Torino, Via Osservatorio 20, 10025 Pino Torinese, (TO), Italy
³⁷ Dipartimento di Fisica, Università di Genova, Via Dodecaneso 33, 16146 Genova, Italy
³⁸ INFN-Sezione di Genova, Via Dodecaneso 33, 16146 Genova, Italy
³⁹ Department of Physics “E. Pancini”, University Federico II, Via Cinthia 6, 80126 Napoli, Italy
⁴⁰ INAF-Osservatorio Astronomico di Capodimonte, Via Moiariello 16, 80131 Napoli, Italy
⁴¹ Faculdade de Ciências da Universidade do Porto, Rua do Campo de Alegre, 4150-007 Porto, Portugal
⁴² Dipartimento di Fisica, Università degli Studi di Torino, Via P. Giuria 1, 10125 Torino, Italy
⁴³ INFN-Sezione di Torino, Via P. Giuria 1, 10125 Torino, Italy
⁴⁴ European Space Agency/ESTEC, Keplerlaan 1, 2201 AZ, Noordwijk, The Netherlands
⁴⁵ Institute Lorentz, Leiden University, Niels Bohrweg 2, 2333, CA, Leiden, The Netherlands
⁴⁶ INAF-IASF Milano, Via Alfonso Corti 12, 20133 Milano, Italy
⁴⁷ Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Avenida Complutense 40, 28040 Madrid, Spain
⁴⁸ Port d’Informació Científica, Campus UAB, C. Albareda s/n, 08193 Bellaterra (Barcelona), Spain
⁴⁹ Institute for Theoretical Particle Physics and Cosmology (TTK), RWTH Aachen University, 52056 Aachen, Germany
⁵⁰ INFN section of Naples, Via Cinthia 6, 80126 Napoli, Italy
⁵¹ Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822, USA
⁵² Dipartimento di Fisica e Astronomia “Augusto Righi” – Alma Mater Studiorum Università di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy
⁵³ Jodrell Bank Centre for Astrophysics, Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
⁵⁴ European Space Agency/ESRIN, Largo Galileo Galilei 1, 00044 Frascati, Roma, Italy
⁵⁵ Université Claude Bernard Lyon 1, CNRS/IN2P3, IP2I Lyon, UMR 5822, Villeurbanne F-69100, France
⁵⁶ Aix-Marseille Université, CNRS, CNES, LAM, Marseille, France
⁵⁷ Institut de Ciències del Cosmos (ICCUB), Universitat de Barcelona (IEEC-UB), Martí i Franquès 1, 08028 Barcelona, Spain
⁵⁸ Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig de Lluís Companys 23, 08010 Barcelona, Spain
⁵⁹ UCB Lyon 1, CNRS/IN2P3, IUF, IP2I Lyon, 4 rue Enrico Fermi, 69622 Villeurbanne, France
⁶⁰ Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT, UK
⁶¹ Departamento de Física, Faculdade de Ciências, Universidade de Lisboa, Edifício C8, Campo Grande, PT1749-016 Lisboa, Portugal
⁶² Instituto de Astrofísica e Ciências do Espaço, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
⁶³ Department of Astronomy, University of Geneva, ch. d’Ecogia 16, 1290 Versoix, Switzerland
⁶⁴ Aix-Marseille Université, CNRS/IN2P3, CPPM, Marseille, France
⁶⁵ INFN-Bologna, Via Irnerio 46, 40126 Bologna, Italy
⁶⁶ Universitäts-Sternwarte München, Fakultät für Physik, Ludwig-Maximilians-Universität München, Scheinerstrasse 1, 81679 München, Germany
⁶⁷ FRACTAL S.L.N.E., calle Tulipán 2, Portal 13 1A, 28231 Las Rozas de Madrid, Spain
⁶⁸ Dipartimento di Fisica “Aldo Pontremoli”, Università degli Studi di Milano, Via Celoria 16, 20133 Milano, Italy
⁶⁹ INFN-Sezione di Milano, Via Celoria 16, 20133 Milano, Italy
⁷⁰ NRC Herzberg, 5071 West Saanich Rd, Victoria, BC V9E 2E7, Canada
⁷¹ Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern 0315, Oslo, Norway
⁷² Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
⁷³ Department of Physics, Lancaster University, Lancaster LA1 4YB, UK
⁷⁴ Felix Hormuth Engineering, Goethestr. 17, 69181 Leimen, Germany
⁷⁵ Technical University of Denmark, Elektrovej 327, 2800 Kgs., Lyngby, Denmark
⁷⁶ Cosmic Dawn Center (DAWN), Denmark
⁷⁷ Institut d’Astrophysique de Paris, UMR 7095, CNRS, and Sorbonne Université, 98 bis boulevard Arago, 75014 Paris, France
⁷⁸ Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
⁷⁹ NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
⁸⁰ Department of Physics and Helsinki Institute of Physics, Gustaf Hällströmin katu 2, 00014 University of Helsinki, Finland
⁸¹ Université de Genève, Département de Physique Théorique and Centre for Astroparticle Physics, 24 quai Ernest-Ansermet, CH-1211 Genève 4, Switzerland
⁸² Department of Physics, P.O. Box 64, 00014 University of Helsinki, Finland
⁸³ Helsinki Institute of Physics, Gustaf Hällströmin katu 2, University of Helsinki, Helsinki, Finland
⁸⁴ Centre de Calcul de l’IN2P3/CNRS, 21 avenue Pierre de Coubertin, 69627 Villeurbanne Cedex, France
⁸⁵ Laboratoire d’etude de l’Univers et des phenomenes eXtremes, Observatoire de Paris, Université PSL, Sorbonne Université, CNRS, 92190 Meudon, France
⁸⁶ SKA Observatory, Jodrell Bank, Lower Withington, Macclesfield, Cheshire SK11 9FT, UK
⁸⁷ University of Applied Sciences and Arts of Northwestern Switzerland, School of Computer Science, 5210 Windisch, Switzerland
⁸⁸ Universität Bonn, Argelander-Institut für Astronomie, Auf dem Hügel 71, 53121 Bonn, Germany
⁸⁹ INFN-Sezione di Roma, Piazzale Aldo Moro, 2 – c/o Dipartimento di Fisica, Edificio G. Marconi, 00185 Roma, Italy
⁹⁰ Dipartimento di Fisica e Astronomia “Augusto Righi” – Alma Mater Studiorum Università di Bologna, Via Piero Gobetti 93/2, 40129 Bologna, Italy
⁹¹ Department of Physics, Institute for Computational Cosmology, Durham University, South Road, Durham DH1 3LE, UK
⁹² Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, Bd de l’Observatoire, CS 34229, 06304 Nice cedex 4, France
⁹³ Université Paris Cité, CNRS, Astroparticule et Cosmologie, 75013 Paris, France
⁹⁴ CNRS-UCB International Research Laboratory, Centre Pierre Binetruy, IRL2007, CPB-IN2P3 Berkeley, USA
⁹⁵ University of Applied Sciences and Arts of Northwestern Switzerland, School of Engineering, 5210 Windisch, Switzerland
⁹⁶ Institut d’Astrophysique de Paris, 98bis Boulevard Arago, 75014 Paris, France
⁹⁷ Institute of Physics, Laboratory of Astrophysics, Ecole Polytechnique Fédérale de Lausanne (EPFL), Observatoire de Sauverny, 1290 Versoix, Switzerland
⁹⁸ Aurora Technology for European Space Agency (ESA), Camino bajo del Castillo, s/n, Urbanizacion Villafranca del Castillo, Villanueva de la Cañada, 28692 Madrid, Spain
⁹⁹ Institut de Física d’Altes Energies (IFAE), The Barcelona Institute of Science and Technology, Campus UAB, 08193 Bellaterra (Barcelona), Spain
¹⁰⁰ School of Mathematics, Statistics and Physics, Newcastle University, Herschel Building, Newcastle-upon-Tyne, NE1 7RU, UK
¹⁰¹ DARK, Niels Bohr Institute, University of Copenhagen, Jagtvej 155, 2200 Copenhagen, Denmark
¹⁰² Waterloo Centre for Astrophysics, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
¹⁰³ Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
¹⁰⁴ Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2L 2Y5, Canada
¹⁰⁵ Centre National d’Etudes Spatiales – Centre spatial de Toulouse, 18 avenue Edouard Belin, 31401 Toulouse Cedex 9, France
¹⁰⁶ Institute of Space Science, Str. Atomistilor, nr. 409 Măgurele, Ilfov 077125, Romania
¹⁰⁷ Consejo Superior de Investigaciones Cientificas, Calle Serrano 117, 28006 Madrid, Spain
¹⁰⁸ Dipartimento di Fisica e Astronomia “G. Galilei”, UniversitUniversità di Padova, Via Marzolo 8, 35131 Padova, Italy
¹⁰⁹ INFN-Padova, Via Marzolo 8, 35131 Padova, Italy
¹¹⁰ Caltech/IPAC, 1200 E. California Blvd., Pasadena, CA 91125, USA
¹¹¹ Institut für Theoretische Physik, University of Heidelberg, Philosophenweg 16, 69120 Heidelberg, Germany
¹¹² Institut de Recherche en Astrophysique et Planétologie (IRAP), Université de Toulouse, CNRS, UPS, CNES, 14 Av. Edouard Belin, 31400 Toulouse, France
¹¹³ Université St Joseph; Faculty of Sciences, Beirut, Lebanon
¹¹⁴ Departamento de Física, FCFM, Universidad de Chile, Blanco Encalada, 2008 Santiago, Chile
¹¹⁵ Universität Innsbruck, Institut für Astro- und Teilchenphysik, Technikerstr. 25/8, 6020 Innsbruck, Austria
¹¹⁶ Satlantis, University Science Park, Sede Bld 48940, Leioa-Bilbao, Spain
¹¹⁷ Instituto de Astrofísica e Ciências do Espaço, Faculdade de Ciências, Universidade de Lisboa, Tapada da Ajuda, 1349-018 Lisboa, Portugal
¹¹⁸ Cosmic Dawn Center (DAWN)
¹¹⁹ Niels Bohr Institute, University of Copenhagen, Jagtvej 128, 2200 Copenhagen, Denmark
¹²⁰ Universidad Politécnica de Cartagena, Departamento de Electrónica y Tecnología de Computadoras, Plaza del Hospital 1, 30202 Cartagena, Spain
¹²¹ Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125, USA
¹²² Dipartimento di Fisica e Scienze della Terra, Università degli Studi di Ferrara, Via Giuseppe Saragat 1, 44122 Ferrara, Italy
¹²³ Istituto Nazionale di Fisica Nucleare, Sezione di Ferrara, Via Giuseppe Saragat 1, 44122 Ferrara, Italy
¹²⁴ INAF, Istituto di Radioastronomia, Via Piero Gobetti 101, 40129 Bologna, Italy
¹²⁵ Department of Physics, Oxford University, Keble Road, Oxford OX1 3RH, UK
¹²⁶ Université PSL, Observatoire de Paris, Sorbonne Université, CNRS, LERMA, 75014 Paris, France
¹²⁷ Université Paris-Cité, 5 Rue Thomas Mann, 75013, Paris, France
¹²⁸ INAF – Osservatorio Astronomico di Brera, Via Emilio Bianchi 46, 23807 Merate, Italy
¹²⁹ INAF-Osservatorio Astronomico di Brera, Via Brera 28, 20122, Milano, Italy and INFN-Sezione di Genova, Via Dodecaneso 33, 16146 Genova, Italy
¹³⁰ ICL, Junia, Université Catholique de Lille, LITL, 59000 Lille, France
¹³¹ ICSC – Centro Nazionale di Ricerca in High Performance Computing, Big Data e Quantum Computing, Via Magnanelli 2, Bologna, Italy
¹³² Instituto de Física Teórica UAM-CSIC, Campus de Cantoblanco, 28049 Madrid, Spain
¹³³ CERCA/ISO, Department of Physics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
¹³⁴ Technical University of Munich, TUM School of Natural Sciences, Physics Department, James-Franck-Str. 1, 85748 Garching, Germany
¹³⁵ Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85748 Garching, Germany
¹³⁶ Laboratoire Univers et Théorie, Observatoire de Paris, Université PSL, Université Paris Cité, CNRS, 92190 Meudon, France
¹³⁷ Departamento de Física Fundamental. Universidad de Salamanca., Plaza de la Merced s/n., 37008 Salamanca, Spain
¹³⁸ Université de Strasbourg, CNRS, Observatoire astronomique de Strasbourg, UMR 7550, 67000 Strasbourg, France
¹³⁹ Center for Data-Driven Discovery, Kavli IPMU (WPI), UTIAS, The University of Tokyo, Kashiwa, Chiba 277-8583, Japan
¹⁴⁰ Ludwig-Maximilians-University, Schellingstrasse 4, 80799 Munich, Germany
¹⁴¹ Max-Planck-Institut für Physik, Boltzmannstr. 8, 85748 Garching, Germany
¹⁴² Dipartimento di Fisica – Sezione di Astronomia, Università di Trieste, Via Tiepolo 11, 34131 Trieste, Italy
¹⁴³ California Institute of Technology, 1200 E California Blvd, Pasadena, CA 91125, USA
¹⁴⁴ Department of Physics & Astronomy, University of California Irvine, Irvine, CA 92697, USA
¹⁴⁵ Department of Mathematics and Physics E. De Giorgi, University of Salento, Via per Arnesano, CP-I93, 73100 Lecce, Italy
¹⁴⁶ INFN, Sezione di Lecce, Via per Arnesano, CP-193, 73100 Lecce, Italy
¹⁴⁷ INAF-Sezione di Lecce, c/o Dipartimento Matematica e Fisica, Via per Arnesano, 73100 Lecce, Italy
¹⁴⁸ Departamento Física Aplicada, Universidad Politécnica de Cartagena, Campus Muralla del Mar, 30202 Cartagena, Murcia, Spain
¹⁴⁹ Instituto de Física de Cantabria, Edificio Juan Jordá, Avenida de los Castros, 39005 Santander, Spain
¹⁵⁰ CEA Saclay, DFR/IRFU, Service d’Astrophysique, Bat. 709, 91191 Gif-sur-Yvette, France
¹⁵¹ Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth PO1 3FX, UK
¹⁵² Department of Computer Science, Aalto University, PO Box 15400 Espoo FI-00 076, Finland
¹⁵³ Instituto de Astrofísica de Canarias, c/ Via Lactea s/n, La Laguna, 38200, Spain. Departamento de Astrofísica de la Universidad de La Laguna, Avda. Francisco Sanchez, La Laguna, 38200, Spain
¹⁵⁴ Ruhr University Bochum, Faculty of Physics and Astronomy, Astronomical Institute (AIRUB), German Centre for Cosmological Lensing (GCCL), 44780 Bochum, Germany
¹⁵⁵ Department of Physics and Astronomy, Vesilinnantie 5, 20014 University of Turku, Finland
¹⁵⁶ Serco for European Space Agency (ESA), Camino bajo del Castillo, s/n, Urbanizacion Villafranca del Castillo, Villanueva de la Cañada, 28692, Madrid, Spain
¹⁵⁷ ARC Centre of Excellence for Dark Matter Particle Physics, Melbourne, Australia
¹⁵⁸ Centre for Astrophysics & Supercomputing, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
¹⁵⁹ Department of Physics and Astronomy, University of the Western Cape, Bellville, Cape Town, 7535, South Africa
¹⁶⁰ DAMTP, Centre for Mathematical Sciences, Wilberforce Road, Cambridge CB3 0WA, UK
¹⁶¹ Kavli Institute for Cosmology Cambridge, Madingley Road, Cambridge CB3 0HA, UK
¹⁶² Department of Astrophysics, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
¹⁶³ Department of Physics, Centre for Extragalactic Astronomy, Durham University, South Road, Durham DH1 3LE, UK
¹⁶⁴ IRFU, CEA, Université Paris-Saclay, 91191 Gif-sur-Yvette Cedex, France
¹⁶⁵ Oskar Klein Centre for Cosmoparticle Physics, Department of Physics, Stockholm University, Stockholm SE-106 91, Sweden
¹⁶⁶ Astrophysics Group, Blackett Laboratory, Imperial College London, London SW7 2AZ, UK
¹⁶⁷ Univ. Grenoble Alpes, CNRS, Grenoble INP, LPSC-IN2P3, 53, Avenue des Martyrs, 38000 Grenoble, France
¹⁶⁸ INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy
¹⁶⁹ Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 2, 00185 Roma, Italy
¹⁷⁰ Centro de Astrofísica da Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal
¹⁷¹ HE Space for European Space Agency (ESA), Camino bajo del Castillo, s/n, Urbanizacion Villafranca del Castillo, Villanueva de la Cañada, 28692, Madrid, Spain
¹⁷² Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544, USA
¹⁷³ Theoretical astrophysics, Department of Physics and Astronomy, Uppsala University, Box 515, 751 20 Uppsala, Sweden
¹⁷⁴ Minnesota Institute for Astrophysics, University of Minnesota, 116 Church St SE, Minneapolis, MN 55455, USA
¹⁷⁵ Mathematical Institute, University of Leiden, Einsteinweg 55, 2333, CA, Leiden, The Netherlands
¹⁷⁶ Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
¹⁷⁷ Space Physics and Astronomy Research Unit, University of Oulu, Pentti Kaiteran katu 1, FI-90014 Oulu, Finland
¹⁷⁸ Center for Computational Astrophysics, Flatiron Institute, 162 5th Avenue, 10010 New York, NY, USA
¹⁷⁹ 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: 17 March 2025
Accepted: 20 September 2025

Abstract

Active galactic nuclei (AGN) are an important phase in galaxy evolution. However, they can be difficult to identify due to their varied observational signatures. Furthermore, to understand the impact of an AGN on its host galaxy, it is important to quantify the strength of the AGN with respect to the host galaxy. We developed a deep learning (DL) model to identify AGN in imaging data by deriving the contribution of the central point source. The model was trained with Euclidised mock galaxy images in which we artificially injected different levels of AGN, in the form of varying contributions of the point spread function (PSF). Our DL-based method can precisely and accurately recover the injected AGN contribution fraction, f_PSF, with a mean difference between the predicted and true f_PSF of −0.0078 and an overall root mean square error of 0.051. With this new method, we move beyond the simplistic AGN versus non-AGN classification and are able to precisely quantify the AGN contribution and study galaxy evolution across a continuous spectrum of AGN activity. We applied our method to a stellar-mass-limited sample (with M_* ≥ 10^9.8 M_⊙ and 0.5 ≤ z ≤ 2.0 ) selected from the first Euclid quick data release (Q1) and, using a threshold of f_PSF > 0.2, we identified 61 432 ± 70 AGN over 63.1 deg² (9.8 ± 0.1% of our sample). We compared these DL-selected AGN with AGN selected in the X-ray, mid-infrared (MIR), and via optical spectroscopy and investigated their overlapping fractions depending on different thresholds on the PSF contribution. We find that the overlap increases with increasing X-ray or bolometric AGN luminosity. We observe a positive correlation between the luminosity in the I_E filter of the AGN and the host galaxy stellar mass, suggesting that supermassive black holes (SMBHs) generally grow faster (in absolute terms, i.e. the luminosity of the PSF component is larger) in more massive galaxies. Moreover, the mean relative contribution of the AGN is higher in the quiescent galaxy population than in the star-forming population. In terms of absolute power, starburst galaxies, as well as the most massive galaxies (across the star-formation main sequence), tend to host the most luminous AGN, indicating concomitant assembly of the SMBH and the host galaxy.