Euclid Quick Data Release (Q1)

Astronomy and Astrophysics, vol. 711, pp. A19

Abstract

Red quasars constitute an important but elusive phase in the evolution of supermassive black holes, where dust obscuration can significantly alter their observed properties. They have broad emission lines, like other quasars, but their optical continuum emission is significantly reddened, which is why they were traditionally identified based on near- and mid-infrared selection criteria. This work showcases the capability of the Euclid space telescope to find a large sample of red quasars, using Euclid near infrared (NIR) photometry. We first conduct a forecast analysis, comparing a synthetic catalogue of red quasars with COSMOS2020. Using template fitting, we reconstruct Euclid -like photometry for the COSMOS sources and identify a sample of candidates in a multi-dimensional colour-colour space achieving 98% completeness for mock red quasars with 30% contaminants. To refine our selection function, we implement a probabilistic Random Forest classifier, and use UMAP visualisation to disentangle non-linear features in colour-space, reaching 98% completeness and 88% purity. A preliminary analysis of the candidates in the Euclid Deep Field Fornax (EDF-F) shows that, compared to VISTA+DECam-based colour selection criteria, Euclid ’s superior depth, resolution, and optical-to-NIR coverage improves the identification of the reddest, most obscured sources. Notably, the Euclid exquisite resolution in the I E filter unveils the presence of a candidate dual quasar system, highlighting the potential for this mission to contribute to future studies on the population of dual AGN. The resulting catalogue of candidates, including more the 150 000 sources, provides a first census of red quasars in Euclid Q1 and sets the groundwork for future studies in the Euclid Wide Survey (EWS), including spectral follow-up analyses and host morphology characterisation.

Authors 80

1. S. Fotopoulou

   University of Bristol

   Affiliation as printed

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

2. M. Banerji

   University of Southampton

   Affiliation as printed

   School of Physics & Astronomy, University of Southampton

3. Andreas L. Faisst

   California Institute of Technology · Infrared Processing and Analysis Center

   Affiliation as printed

   Caltech/IPAC

4. M. Tucci

   University of Geneva

   Affiliation as printed

   Department of Astronomy, University of Geneva

5. Sandro Tacchella

   University of Cambridge

   Affiliation as printed

   Kavli Institute for Cosmology Cambridge

6. 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

7. Hermine Landt

   Durham University

   Affiliation as printed

   Department of Physics, Centre for Extragalactic Astronomy, Durham University

8. Y. Fu Aachen Leiden Observatory

   Leiden University · University of Groningen · Leiden Observatory

   Affiliation as printed

   Kapteyn Astronomical Institute, University of Groningen

   Leiden Observatory, Leiden University

9. P. A. C. Cunha

   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

10. K. Duncan

    University of Edinburgh

    Affiliation as printed

    Institute for Astronomy, University of Edinburgh

11. W. Roster

    Max Planck Institute for Extraterrestrial Physics

    Affiliation as printed

    Max Planck Institute for Extraterrestrial Physics

12. M. Salvato

    Max Planck Institute for Extraterrestrial Physics

    Affiliation as printed

    Max Planck Institute for Extraterrestrial Physics

13. Brivael Laloux

    Astronomical Observatory of Capodimonte · Max Planck Institute for Extraterrestrial Physics · National Institute for Astrophysics

    Affiliation as printed

    INAF-Osservatorio Astronomico di Capodimonte

    Max Planck Institute for Extraterrestrial Physics

14. Federica Ricci

    Roma Tre University · Astronomical Observatory of Rome · National Institute for Astrophysics

    Affiliation as printed

    Department of Mathematics and Physics, Roma Tre University

    INAF-Osservatorio Astronomico di Roma

15. 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

16. B. Altieri

    European Space Agency · European Space Astronomy Centre

    Affiliation as printed

    ESAC/ESA

17. A Amara

    University of Surrey

    Affiliation as printed

    School of Mathematics and Physics, University of Surrey

18. Stefano Andreon

    Brera Astronomical Observatory · National Institute for Astrophysics

    Affiliation as printed

    INAF-Osservatorio Astronomico di Brera

19. N. Auricchio

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

    Affiliation as printed

    INAF-Osservatorio di Astrofísica e Scienza dello Spazio di Bologna

20. 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

21. 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

22. 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 Astrofísica e Scienza dello Spazio di Bologna

    INFN-Sezione di Bologna

23. A. Balestra

    Osservatorio Astronomico di Padova · National Institute for Astrophysics

    Affiliation as printed

    INAF-Osservatorio Astronomico di Padova

24. S. Bardelli

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

    Affiliation as printed

    INAF-Osservatorio di Astrofísica e Scienza dello Spazio di Bologna

25. 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

26. Andrea Bonchi

    Agenzia Spaziale Italiana

    Affiliation as printed

    Space Science Data Center, Italian Space Agency

27. 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

28. 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

29. 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

30. 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

31. 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

32. Santiago Casas Aachen Institute for Theoretical Particle Physics and Cosmology

    RWTH Aachen University

    Affiliation as printed

    Institute for Theoretical Particle Physics and Cosmology (TTK), RWTH Aachen University

33. G. Castignani

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

    Affiliation as printed

    INAF-Osservatorio di Astrofísica e Scienza dello Spazio di Bologna

34. 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

35. K. C. Chambers

    University of Hawaiʻi at Mānoa · University of Hawaii System

    Affiliation as printed

    Institute for Astronomy, University of Hawaii

36. A Cimatti

    University of Bologna

    Affiliation as printed

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

37. C Colodro-Conde

    Instituto de Astrofísica de Canarias

    Affiliation as printed

    Instituto de Astrofísica de Canarias

38. Christopher J. Conselice

    University of Manchester

    Affiliation as printed

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

39. L. Conversi

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

    Affiliation as printed

    ESAC/ESA

    European Space Agency/ESRIN

40. A. Costille

    Centre National de la Recherche Scientifique · Aix-Marseille Université

    Affiliation as printed

    Aix-Marseille Université, CNRS, CNES, LAM

41. Mark S. Cropper

    University College London

    Affiliation as printed

    Mullard Space Science Laboratory, University College London

42. 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

43. Hubert Degaudenzi

    University of Geneva

    Affiliation as printed

    Department of Astronomy, University of Geneva

44. G. De Lucia

    Trieste Astronomical Observatory · National Institute for Astrophysics

    Affiliation as printed

    INAF-Osservatorio Astronomico di Trieste

45. Anna M. Di Giorgio

    Institute for Space Astrophysics and Planetology · National Institute for Astrophysics

    Affiliation as printed

    INAF-Istituto di Astrofisica e Planetologia Spaziali

46. C. Dolding

    University College London

    Affiliation as printed

    Mullard Space Science Laboratory, University College London

47. H. 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

48. F. Dubath

    University of Geneva

    Affiliation as printed

    Department of Astronomy, University of Geneva

49. C. A. J. Duncan

    University of Manchester

    Affiliation as printed

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

50. X. Dupac

    European Space Agency · European Space Astronomy Centre

    Affiliation as printed

    ESAC/ESA

51. 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

52. Maria Farina

    Institute for Space Astrophysics and Planetology · National Institute for Astrophysics

    Affiliation as printed

    INAF-Istituto di Astrofisica e Planetologia Spaziali

53. R. Farinelli

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

    Affiliation as printed

    INAF-Osservatorio di Astrofísica e Scienza dello Spazio di Bologna

54. 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

55. 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

56. 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 Astrofísica e Scienza dello Spazio di Bologna

    INFN-Bologna

57. M. Frailis

    Trieste Astronomical Observatory · National Institute for Astrophysics

    Affiliation as printed

    INAF-Osservatorio Astronomico di Trieste

58. Enrico Franceschi

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

    Affiliation as printed

    INAF-Osservatorio di Astrofísica e Scienza dello Spazio di Bologna

59. Samuele Galeotta

    Trieste Astronomical Observatory · National Institute for Astrophysics

    Affiliation as printed

    INAF-Osservatorio Astronomico di Trieste

60. William Gillard

    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

61. Gillis B

    University of Edinburgh

    Affiliation as printed

    Institute for Astronomy, University of Edinburgh

62. P. Gómez-Álvarez

    European Space Agency · European Space Astronomy Centre

    Affiliation as printed

    ESAC/ESA

    FRACTAL S.L.N.E

63. J. Graciá‐Carpio

    Max Planck Institute for Extraterrestrial Physics

    Affiliation as printed

    Max Planck Institute for Extraterrestrial Physics

64. B. R. Granett

    Brera Astronomical Observatory · National Institute for Astrophysics

    Affiliation as printed

    INAF-Osservatorio Astronomico di Brera

65. Frank U. 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

66. S Gwyn

    Herzberg Institute of Astrophysics · National Research Council Canada

    Affiliation as printed

    NRC Herzberg

67. S. V. H. Haugan

    University of Oslo

    Affiliation as printed

    Institute of Theoretical Astrophysics, University of Oslo

68. W. Holmes

    Jet Propulsion Laboratory

    Affiliation as printed

    Jet Propulsion Laboratory, California Institute of Technology

69. I. Hook

    Lancaster University

    Affiliation as printed

    Department of Physics, Lancaster University

70. 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

71. K. Jahnkę

    Max Planck Institute for Astronomy

    Affiliation as printed

    Max-Planck-Institut für Astronomie

72. Murzy D. Jhabvala

    Goddard Space Flight Center

    Affiliation as printed

    NASA Goddard Space Flight Center

73. 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

74. A. Kiessling

    Jet Propulsion Laboratory

    Affiliation as printed

    Jet Propulsion Laboratory, California Institute of Technology

75. Bogna Kubik

    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

76. M. Kümmel

    Ludwig-Maximilians-Universität München

    Affiliation as printed

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

77. Martin Kunz

    University of Geneva

    Affiliation as printed

    Université de Genève, Département de Physique Théorique and Centre for Astroparticle Physics

78. Hannu Kurki-Suonio

    Helsinki Institute of Physics

    Affiliation as printed

    Department of Physics

    Helsinki Institute of Physics

79. Q. Le Boulc'h

    Centre National de la Recherche Scientifique · Centre de Calcul de l’Institut National de Physique Nucléaire et de Physique des Particules

    Affiliation as printed

    Centre de Calcul de l’IN2P3/CNRS

80. Amandine M. C. Le Brun

    Centre National de la Recherche Scientifique · Université Paris Sciences et Lettres · Observatoire de Paris · Sorbonne Université · Laboratoire d'Étude de l'Univers et des Phénomènes Extrêmes

    Affiliation as printed

    Laboratoire d’etude de l’Univers et des phenomenes eXtremes, Observatoire de Paris, Université PSL, Sorbonne Université, CNRS