• DOI:10.1038/nature25180
• Corpus ID: 205263326

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

@article{Baados2018An8B,
  title={An 800-million-solar-mass black hole in a significantly neutral Universe at a redshift of 7.5},
  author={Eduardo Ba{\~n}ados and Bram P. Venemans and Chiara Mazzucchelli and Emanuele Paolo Farina and Fabian Walter and Feige Wang and Roberto Decarli and Daniel Stern and Xiaohui Fan and Frederick B. Davies and Joseph F. Hennawi and Robert A. Simcoe and Monica L. Turner and Hans-Walter Rix and Jinyi Yang and Daniel D. Kelson and Gwen C. Rudie and Jack M. Winters},
  journal={Nature},
  year={2018},
  volume={553},
  pages={473-476}
}

• E. Bañados, B. Venemans, +15 authors J. Winters
• Published 5 December 2017
• Physics
• Nature

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 × 1013 times the luminosity of the Sun and a black-hole mass of 8 × 108 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 104 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.