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An 800-million-solar-mass black hole in a significantly neutral Universe at a redshift of 7.5

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Quasars are the most luminous non-transient objects known, and as such they enable studies of the Universe at the earliest cosmic epochs. Despite extensive efforts, however, the quasar ULAS J1120+0641 at redshift z = 7.09 (hereafter J1120+0641) has remained the only one known at z > 7 for more than half a decade1. Here we report observations of the quasar ULAS J134208.10+092838.61 (hereafter J1342+0928) at a redshift of z = 7.54. This quasar has a bolometric luminosity of 4 × 1014L and a black hole mass of 8 × 108M. The existence of this supermassive black hole when the Universe was only 690 million years old, just five per cent of its current age, reinforces early models of black hole growth that allow black holes with initial masses of more than about 104M (refs 2, 3) or episodic hyper-Eddington accretion4,5. We see strong evidence of the quasar’s Lyα emission line being absorbed by a Gunn–Peterson damping wing from the intergalactic medium, as would be expected if the intergalactic hydrogen surrounding J1342+0928 is significantly neutral. We derive a significant neutral fraction, although the exact value depends on the modelling. However, even in our most conservative analysis we find xHI > 0.33 (xHI > 0.11) at 68 per cent (95 per cent) probability, indicating that we are probing well within the reionization epoch.

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Author information


  1. The Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, California 91101, USA

    • Eduardo Bañados
    • , Daniel D. Kelson
    •  & Gwen Rudie
  2. Max Planck Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg, Germany

    • Bram P. Venemans
    • , Chiara Mazzucchelli
    • , Emanuele P. Farina
    • , Fabian Walter
    • , Feige Wang
    • , Roberto Decarli
    •  & Hans-Walter Rix
  3. Department of Astronomy, School of Physics, Peking University, Beijing 100871, China

    • Feige Wang
    •  & Jinyi Yang
  4. Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871, China

    • Jinyi Yang
  5. INAF—Osservatorio Astronomico di Bologna, via Gobetti 93/3, 40129 Bologna, Italy

    • Roberto Decarli
  6. Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, USA

    • Daniel Stern
  7. Steward Observatory, The University of Arizona, 933 North Cherry Avenue, Tucson, Arizona 85721-0065, USA

    • Xiaohui Fan
  8. Department of Physics, Broida Hall, University of California, Santa Barbara, California 93106-9530, USA

    • Fred Davies
    •  & Joseph F. Hennawi
  9. MIT-Kavli Center for Astrophysics and Space Research, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA

    • Rob Simcoe
    •  & Monica L. Turner
  10. Las Cumbres Observatory, 6740 Cortona Drive, Goleta, California 93117, USA

    • Monica L. Turner
  11. Institut de Radioastronomie Millimétrique (IRAM), 300 rue de la Piscine, 38406 Saint Martin d’Hères, France

    • Jan Martin Winters


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Corresponding author

Correspondence to Eduardo Bañados.


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