Euclid Quick Data Release (Q1)

Astronomy and Astrophysics, vol. 711, pp. A17

Abstract

Galaxy major mergers are indicated as one of the principal pathways to trigger active galactic nuclei (AGN). We present the first statistical analysis of the major merger and AGN connection in the Euclid Deep Fields, and showcase the statistical power of the Euclid data. We constructed a stellar-mass-complete ( M ★ > 10 9.8 M ⊙ ) sample of galaxies from the quick data release (Euclid Quick Release Q1 2025) in the redshift range z = 0.5–2. We selected AGN using X-ray detections, optical spectroscopy, and mid-infrared (MIR) colours, and by processing I E observations with an image decomposition algorithm. We used convolutional neural networks trained on cosmological hydrodynamic simulations to classify galaxies as mergers and non-mergers. We found a larger fraction of AGN in mergers compared to the non-merger controls for all AGN selections, with AGN excess factors ranging from two to six. The largest excess we observed was in the MIR AGN. Likewise, a generally larger merger fraction ( f merg ) was seen in active galaxies than in the non-active controls, with the excess depending on the AGN selection method. Furthermore, we analysed f merg as a function of the AGN bolometric luminosity ( L bol ) and the contribution of the point-source component to the total galaxy light in the I E -band ( f PSF ) as a proxy for the relative AGN contribution fraction. We uncovered a rising f merg , with an increasing f PSF up to f PSF ≃ 0.55, after which we observed a decreasing trend. In the range f PSF = 0.3–0.7, mergers appear to be the dominant AGN fuelling mechanism. We then derived the point-source luminosity ( L PSF ) and showed that f merg monotonically increases as a function of L PSF at z < 0.9, with f merg ≥ 50% for L PSF ≃ 2 × 10 43 erg s −1 . Similarly, at 0.9 ≤ z ≤ 2, f merg rises as a function of L PSF , though mergers do not dominate until L PSF ≃ 10 45 erg s −1 . For the X-ray and spectroscopically detected AGN, we derived the bolometric luminosity, L bol , which has a positive correlation with f merg for X-ray AGN, while there is a less pronounced trend for spectroscopically selected AGN due to the smaller sample size. At L bol > 10 45 erg s −1 , AGN mostly reside in mergers. We conclude that mergers are most strongly associated with the most powerful and dust-obscured AGN, which are typically linked to a fast-growing phase of the supermassive black hole, while other mechanisms, such as secular processes, might be the trigger of less luminous and dominant AGN.

Authors 93

1. Antonio La Marca Aachen SRON Netherlands Institute for Space Research

   University of Groningen · Space Research Organisation Netherlands

   Affiliation as printed

   Kapteyn Astronomical Institute, University of Groningen

   SRON Netherlands Institute for Space Research

2. Lingyu Wang Aachen SRON Netherlands Institute for Space Research

   University of Groningen · Space Research Organisation Netherlands

   Affiliation as printed

   Kapteyn Astronomical Institute, University of Groningen

   SRON Netherlands Institute for Space Research

3. Berta Margalef-Bentabol Aachen SRON Netherlands Institute for Space Research

   Space Research Organisation Netherlands

   Affiliation as printed

   SRON Netherlands Institute for Space Research

4. L. Gabarra

   University of Oxford

   Affiliation as printed

   Department of Physics, Oxford University

5. Yoshiki Toba

   Institute of Astronomy and Astrophysics, Academia Sinica · Ritsumeikan University · National Astronomical Observatory of Japan · Academia Sinica

   Affiliation as printed

   Academia Sinica Institute of Astronomy and Astrophysics (ASIAA)

   Department of Physical Sciences, Ritsumeikan University

   National Astronomical Observatory of Japan

6. Mar Mezcua

   Institute of Space Sciences · Institut d'Estudis Espacials de Catalunya

   Affiliation as printed

   Institut d’Estudis Espacials de Catalunya (IEEC)

   Institute of Space Sciences (ICE, CSIC)

7. Vicente Rodríguez-Gómez

   Universidad Nacional Autónoma de México

   Affiliation as printed

   Instituto de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México

8. S. Fotopoulou

   University of Bristol

   Affiliation as printed

   School of Physics, HH Wills Physics Laboratory, University of Bristol

9. T. Matamoro Zatarain

   University of Bristol

   Affiliation as printed

   School of Physics, HH Wills Physics Laboratory, University of Bristol

10. V. Allevato

    Astronomical Observatory of Capodimonte · National Institute for Astrophysics

    Affiliation as printed

    INAF-Osservatorio Astronomico di Capodimonte

11. Fabio La Franca

    Roma Tre University

    Affiliation as printed

    Department of Mathematics and Physics, Roma Tre University

12. F. Shankar

    University of Southampton

    Affiliation as printed

    School of Physics & Astronomy, University of Southampton

13. L Bisigello

    Osservatorio Astronomico di Padova · National Institute for Astrophysics

    Affiliation as printed

    INAF-Osservatorio Astronomico di Padova

14. M. Siudek

    Institute of Space Sciences · Universidad de La Laguna · Instituto de Astrofísica de Canarias

    Affiliation as printed

    Institute of Space Sciences (ICE, CSIC)

    Instituto de Astrofísica de Canarias (IAC); Departamento de Astrofísica, Universidad de La Laguna (ULL)

15. W. Roster

    Max Planck Institute for Extraterrestrial Physics

    Affiliation as printed

    Max Planck Institute for Extraterrestrial Physics

16. Luigi Spinoglio

    Institute for Space Astrophysics and Planetology · National Institute for Astrophysics

    Affiliation as printed

    INAF-Istituto di Astrofisica e Planetologia Spaziali

17. Allison W. S. Man

    University of British Columbia

    Affiliation as printed

    Department of Physics and Astronomy, University of British Columbia

18. Johan H. Knapen

    Universidad de La Laguna · Instituto de Astrofísica de Canarias

    Affiliation as printed

    Instituto de Astrofísica de Canarias

    Universidad de La Laguna, Departamento de Astrofísica

19. M. Baes

    Ghent University

    Affiliation as printed

    Sterrenkundig Observatorium, Universiteit Gent

20. David O’Ryan

    European Space Agency · European Space Astronomy Centre

    Affiliation as printed

    ESAC/ESA

21. N. Aghanim

    Centre National de la Recherche Scientifique · Université Paris-Saclay · Institut d'Astrophysique Spatiale

    Affiliation as printed

    Université Paris-Saclay, CNRS, Institut d’astrophysique spatiale

22. B Altieri

    European Space Agency · European Space Astronomy Centre

    Affiliation as printed

    ESAC/ESA

23. A Amara

    University of Surrey

    Affiliation as printed

    School of Mathematics and Physics, University of Surrey

24. Stefano Andreon

    Brera Astronomical Observatory · National Institute for Astrophysics

    Affiliation as printed

    INAF-Osservatorio Astronomico di Brera

25. N. Auricchio

    Osservatorio di Astrofisica e Scienza dello Spazio · National Institute for Astrophysics

    Affiliation as printed

    INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna

26. Hervé Aussel

    Centre National de la Recherche Scientifique · Université Paris Cité · Commissariat à l'Énergie Atomique et aux Énergies Alternatives · Université Paris-Saclay · Astrophysique, Instrumentation et Modélisation

    Affiliation as printed

    Université Paris-Saclay, Université Paris Cité, CEA, CNRS, AIM

27. Carlo Baccigalupi

    Scuola Internazionale Superiore di Studi Avanzati · Trieste Astronomical Observatory · Istituto Nazionale di Fisica Nucleare, Sezione di Trieste · Institute for Fundamental Physics of the Universe · National Institute for Astrophysics

    Affiliation as printed

    IFPU, Institute for Fundamental Physics of the Universe

    INAF-Osservatorio Astronomico di Trieste

    INFN, Sezione di Trieste

    SISSA, International School for Advanced Studies

28. Marco Baldi

    Istituto Nazionale di Fisica Nucleare, Sezione di Bologna · Osservatorio di Astrofisica e Scienza dello Spazio · National Institute for Astrophysics · University of Bologna

    Affiliation as printed

    Dipartimento di Fisica e Astronomia, Università di Bologna

    INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna

    INFN-Sezione di Bologna

29. S. Bardelli

    Osservatorio di Astrofisica e Scienza dello Spazio · National Institute for Astrophysics

    Affiliation as printed

    INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna

30. A. Biviano

    Trieste Astronomical Observatory · Institute for Fundamental Physics of the Universe · National Institute for Astrophysics

    Affiliation as printed

    IFPU, Institute for Fundamental Physics of the Universe

    INAF-Osservatorio Astronomico di Trieste

31. E. Branchini

    Brera Astronomical Observatory · Istituto Nazionale di Fisica Nucleare, Sezione di Genova · University of Genoa · National Institute for Astrophysics

    Affiliation as printed

    Dipartimento di Fisica, Università di Genova

    INAF-Osservatorio Astronomico di Brera

    INFN-Sezione di Genova

32. M. Brescia

    Astronomical Observatory of Capodimonte · University of Naples Federico II · National Institute for Astrophysics

    Affiliation as printed

    Department of Physics “E. Pancini”, University Federico II

    INAF-Osservatorio Astronomico di Capodimonte

33. J. Brinchmann

    Universidade do Porto · Institute of Astrophysics and Space Sciences · Centro de Astrofísica da Universidade do Porto

    Affiliation as printed

    Faculdade de Ciências da Universidade do Porto

    Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP

34. S. Camera

    Istituto Nazionale di Fisica Nucleare, Sezione di Torino · Osservatorio Astrofisico di Torino · University of Turin · National Institute for Astrophysics

    Affiliation as printed

    Dipartimento di Fisica, Università degli Studi di Torino

    INAF-Osservatorio Astrofisico di Torino

    INFN-Sezione di Torino

35. G Cañas-Herrera Aachen Institute Lorentz Leiden Observatory

    Leiden University · European Space Agency · Leiden Observatory · European Space Research and Technology Centre

    Affiliation as printed

    European Space Agency/ESTEC

    Institute Lorentz, Leiden University

    Leiden Observatory, Leiden University

36. V. Capobianco

    Osservatorio Astrofisico di Torino · National Institute for Astrophysics

    Affiliation as printed

    INAF-Osservatorio Astrofisico di Torino

37. C. Carbone

    National Institute for Astrophysics

    Affiliation as printed

    INAF-IASF Milano

38. J. Carretero

    Port d'Informació Científica · Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas

    Affiliation as printed

    Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT)

    Port d’Informació Científica

39. M Castellano

    Astronomical Observatory of Rome · National Institute for Astrophysics

    Affiliation as printed

    INAF-Osservatorio Astronomico di Roma

40. G. Castignani

    Osservatorio di Astrofisica e Scienza dello Spazio · National Institute for Astrophysics

    Affiliation as printed

    INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna

41. S. Cavuoti

    Istituto Nazionale di Fisica Nucleare · Astronomical Observatory of Capodimonte · Istituto Nazionale di Fisica Nucleare, Sezione di Napoli · National Institute for Astrophysics

    Affiliation as printed

    INAF-Osservatorio Astronomico di Capodimonte

    INFN section of Naples

42. K. C. Chambers

    University of Hawaiʻi at Mānoa · University of Hawaii System

    Affiliation as printed

    Institute for Astronomy, University of Hawaii

43. A. Cimatti

    University of Bologna

    Affiliation as printed

    Dipartimento di Fisica e Astronomia “Augusto Righi” – Alma Mater Studiorum Università di Bologna

44. C Colodro-Conde

    Instituto de Astrofísica de Canarias

    Affiliation as printed

    Instituto de Astrofísica de Canarias

45. G. Congedo

    Royal Observatory · University of Edinburgh

    Affiliation as printed

    Institute for Astronomy, University of Edinburgh, Royal Observatory

46. Christopher J. Conselice

    University of Manchester

    Affiliation as printed

    Jodrell Bank Centre for Astrophysics, Department of Physics and Astronomy, University of Manchester

47. L. Conversi

    European Space Agency · European Space Astronomy Centre · European Space Research Institute

    Affiliation as printed

    ESAC/ESA

    European Space Agency/ESRIN

48. Y. Copin

    Lyon 1 Université · Centre National de la Recherche Scientifique · Institut National de Physique Nucléaire et de Physique des Particules · Institut de Physique des 2 Infinis de Lyon

    Affiliation as printed

    Université Claude Bernard Lyon 1, CNRS/IN2P3, IP2I Lyon, UMR 5822

49. A. Costille

    Centre National de la Recherche Scientifique · Aix-Marseille Université

    Affiliation as printed

    Aix-Marseille Université, CNRS, CNES, LAM

50. F Courbin

    Institució Catalana de Recerca i Estudis Avançats · Institut de Ciències del Cosmos · Universitat de Barcelona

    Affiliation as printed

    Institució Catalana de Recerca i Estudis Avançats (ICREA)

    Institut de Ciències del Cosmos (ICCUB), Universitat de Barcelona (IEEC-UB)

51. Hélène M. Courtois

    Centre National de la Recherche Scientifique · Institut National de Physique Nucléaire et de Physique des Particules · Institut de Physique des 2 Infinis de Lyon

    Affiliation as printed

    UCB Lyon 1, CNRS/IN2P3, IUF, IP2I Lyon

52. Mark S. Cropper

    University College London

    Affiliation as printed

    Mullard Space Science Laboratory, University College London

53. A da Silva

    University of Lisbon · Institute of Astrophysics and Space Sciences

    Affiliation as printed

    Departamento de Física, Faculdade de Ciências, Universidade de Lisboa

    Instituto de Astrofísica e Ciências do Espaço, Faculdade de Ciências, Universidade de Lisboa

54. Hubert Degaudenzi

    University of Geneva

    Affiliation as printed

    Department of Astronomy, University of Geneva

55. G. De Lucia

    Trieste Astronomical Observatory · National Institute for Astrophysics

    Affiliation as printed

    INAF-Osservatorio Astronomico di Trieste

56. Anna M. Di Giorgio

    Institute for Space Astrophysics and Planetology · National Institute for Astrophysics

    Affiliation as printed

    INAF-Istituto di Astrofisica e Planetologia Spaziali

57. C. Dolding

    University College London

    Affiliation as printed

    Mullard Space Science Laboratory, University College London

58. Herve A. Dole

    Centre National de la Recherche Scientifique · Université Paris-Saclay · Institut d'Astrophysique Spatiale

    Affiliation as printed

    Université Paris-Saclay, CNRS, Institut d’astrophysique spatiale

59. F. Dubath

    University of Geneva

    Affiliation as printed

    Department of Astronomy, University of Geneva

60. C. A. J. Duncan

    University of Manchester

    Affiliation as printed

    Jodrell Bank Centre for Astrophysics, Department of Physics and Astronomy, University of Manchester

61. X. Dupac

    European Space Agency · European Space Astronomy Centre

    Affiliation as printed

    ESAC/ESA

62. A. Ealet

    Lyon 1 Université · Centre National de la Recherche Scientifique · Institut National de Physique Nucléaire et de Physique des Particules · Institut de Physique des 2 Infinis de Lyon

    Affiliation as printed

    Université Claude Bernard Lyon 1, CNRS/IN2P3, IP2I Lyon, UMR 5822

63. S. Escoffier

    Centre National de la Recherche Scientifique · Aix-Marseille Université · Centre de physique des particules de Marseille · Institut National de Physique Nucléaire et de Physique des Particules

    Affiliation as printed

    Aix-Marseille Université, CNRS/IN2P3, CPPM

64. Maximilian Fabricius

    Max Planck Institute for Extraterrestrial Physics · Ludwig-Maximilians-Universität München

    Affiliation as printed

    Max Planck Institute for Extraterrestrial Physics

    Universitäts-Sternwarte München, Fakultät für Physik, Ludwig-Maximilians-Universität München

65. Maria Farina

    Institute for Space Astrophysics and Planetology · National Institute for Astrophysics

    Affiliation as printed

    INAF-Istituto di Astrofisica e Planetologia Spaziali

66. R. Farinelli

    Osservatorio di Astrofisica e Scienza dello Spazio · National Institute for Astrophysics

    Affiliation as printed

    INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna

67. F Faustini

    Astronomical Observatory of Rome · Agenzia Spaziale Italiana · National Institute for Astrophysics

    Affiliation as printed

    INAF-Osservatorio Astronomico di Roma

    Space Science Data Center, Italian Space Agency

68. S Ferriol

    Lyon 1 Université · Centre National de la Recherche Scientifique · Institut National de Physique Nucléaire et de Physique des Particules · Institut de Physique des 2 Infinis de Lyon

    Affiliation as printed

    Université Claude Bernard Lyon 1, CNRS/IN2P3, IP2I Lyon, UMR 5822

69. Fabio Finelli

    Istituto Nazionale di Fisica Nucleare, Sezione di Bologna · Osservatorio di Astrofisica e Scienza dello Spazio · National Institute for Astrophysics

    Affiliation as printed

    INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna

    INFN-Bologna

70. M. Frailis

    Trieste Astronomical Observatory · National Institute for Astrophysics

    Affiliation as printed

    INAF-Osservatorio Astronomico di Trieste

71. Enrico Franceschi

    Osservatorio di Astrofisica e Scienza dello Spazio · National Institute for Astrophysics

    Affiliation as printed

    INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna

72. Samuele Galeotta

    Trieste Astronomical Observatory · National Institute for Astrophysics

    Affiliation as printed

    INAF-Osservatorio Astronomico di Trieste

73. Koshy George

    Ludwig-Maximilians-Universität München

    Affiliation as printed

    Universitäts-Sternwarte München, Fakultät für Physik, Ludwig-Maximilians-Universität München

74. Bryan R. Gillis

    Royal Observatory · University of Edinburgh

    Affiliation as printed

    Institute for Astronomy, University of Edinburgh, Royal Observatory

75. C. Giocoli

    Istituto Nazionale di Fisica Nucleare, Sezione di Bologna · Osservatorio di Astrofisica e Scienza dello Spazio · National Institute for Astrophysics

    Affiliation as printed

    INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna

    INFN-Sezione di Bologna

76. P. Gómez-Álvarez

    European Space Agency · European Space Astronomy Centre

    Affiliation as printed

    ESAC/ESA

    FRACTAL S.L.N.E

77. Javier Graciá-Carpio

    Max Planck Institute for Extraterrestrial Physics

    Affiliation as printed

    Max Planck Institute for Extraterrestrial Physics

78. B. R. Granett

    Brera Astronomical Observatory · National Institute for Astrophysics

    Affiliation as printed

    INAF-Osservatorio Astronomico di Brera

79. A. Grazian

    Osservatorio Astronomico di Padova · National Institute for Astrophysics

    Affiliation as printed

    INAF-Osservatorio Astronomico di Padova

80. F Grupp

    Max Planck Institute for Extraterrestrial Physics · Ludwig-Maximilians-Universität München

    Affiliation as printed

    Max Planck Institute for Extraterrestrial Physics

    Universitäts-Sternwarte München, Fakultät für Physik, Ludwig-Maximilians-Universität München

81. Stephen Gwyn

    Herzberg Institute of Astrophysics · National Research Council Canada

    Affiliation as printed

    NRC Herzberg

82. S. V. H. Haugan

    University of Oslo

    Affiliation as printed

    Institute of Theoretical Astrophysics, University of Oslo

83. W. A. Holmes

    Jet Propulsion Laboratory

    Affiliation as printed

    Jet Propulsion Laboratory, California Institute of Technology

84. I. Hook

    Lancaster University

    Affiliation as printed

    Department of Physics, Lancaster University

85. F. Hormuth
    Affiliation as printed

    Felix Hormuth Engineering

86. Allan Hornstrup

    Technical University of Denmark

    Affiliation as printed

    Cosmic Dawn Center (DAWN)

    Technical University of Denmark

87. Patrick Hudelot

    Centre National de la Recherche Scientifique · Institut d'Astrophysique de Paris · Sorbonne Université

    Affiliation as printed

    Institut d’Astrophysique de Paris, UMR 7095, CNRS, and Sorbonne Université

88. K. Jahnkę

    Max Planck Institute for Astronomy

    Affiliation as printed

    Max-Planck-Institut für Astronomie

89. Murzy D. Jhabvala

    Goddard Space Flight Center

    Affiliation as printed

    NASA Goddard Space Flight Center

90. Benjamin Joachimi

    University College London

    Affiliation as printed

    Department of Physics and Astronomy, University College London

91. Elina Keihänen

    Helsinki Institute of Physics

    Affiliation as printed

    Department of Physics and Helsinki Institute of Physics

92. Smaïn Kermiche

    Centre National de la Recherche Scientifique · Aix-Marseille Université · Centre de physique des particules de Marseille · Institut National de Physique Nucléaire et de Physique des Particules

    Affiliation as printed

    Aix-Marseille Université, CNRS/IN2P3, CPPM

93. A. Kiessling

    Jet Propulsion Laboratory

    Affiliation as printed

    Jet Propulsion Laboratory, California Institute of Technology