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

Eduardo Bañados, Bram P. Venemans, Chiara Mazzucchelli, Emanuele P. Farina, Fabian Walter, Feige Wang, Roberto Decarli, Daniel Stern, Xiaohui Fan, Frederick B. Davies, Joseph F. Hennawi, Robert A. Simcoe, Monica L. Turner, Hans Walter Rix, Jinyi Yang, Daniel D. Kelson, Gwen C. Rudie, Jan Martin Winters

Research output: Contribution to journalArticlepeer-review

744 Scopus citations


Quasars are the most luminous non-Transient objects known and as a result 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 has remained the only one known at z > 7 for more than half a decade. Here we report observations of the quasar ULAS J134208.10 + 092838.61 (hereafter J1342 + 0928) at redshift z = 7.54. This quasar has a bolometric luminosity of 4 × 10 13 times the luminosity of the Sun and a black-hole mass of 8 × 10 8 solar masses. 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 models of early black-hole growth that allow black holes with initial masses of more than about 10 4 solar masses or episodic hyper-Eddington accretion. We see strong evidence of absorption of the spectrum of the quasar redwards of the Lyman α emission line (the Gunn-Peterson damping wing), as would be expected if a significant amount (more than 10 per cent) of the hydrogen in the intergalactic medium surrounding J1342 + 0928 is neutral. We derive such a significant fraction of neutral hydrogen, although the exact fraction depends on the modelling. However, even in our most conservative analysis we find a fraction of more than 0.33 (0.11) at 68 per cent (95 per cent) probability, indicating that we are probing well within the reionization epoch of the Universe.

Original languageEnglish (US)
Pages (from-to)473-476
Number of pages4
Issue number7689
StatePublished - Jan 25 2018

ASJC Scopus subject areas

  • General


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