Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

A luminous quasar at a redshift of z = 7.085

Abstract

The intergalactic medium was not completely reionized until approximately a billion years after the Big Bang, as revealed1 by observations of quasars with redshifts of less than 6.5. It has been difficult to probe to higher redshifts, however, because quasars have historically been identified2,3,4 in optical surveys, which are insensitive to sources at redshifts exceeding 6.5. Here we report observations of a quasar (ULAS J112001.48+064124.3) at a redshift of 7.085, which is 0.77 billion years after the Big Bang. ULAS J1120+0641 has a luminosity of 6.3 × 1013L and hosts a black hole with a mass of 2 × 109M (where L and M are the luminosity and mass of the Sun). The measured radius of the ionized near zone around ULAS J1120+0641 is 1.9 megaparsecs, a factor of three smaller than is typical for quasars at redshifts between 6.0 and 6.4. The near-zone transmission profile is consistent with a Lyα damping wing5, suggesting that the neutral fraction of the intergalactic medium in front of ULAS J1120+0641 exceeded 0.1.

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Prices vary by article type

from$1.95

to$39.95

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Spectrum of ULAS J1120+0641 and a composite spectrum derived from lower redshift quasars.
Figure 2: The observed Lyα absorption measured towards ULAS J1120+0641 and two lower-redshift quasars.
Figure 3: The inferred Lyα near-zone transmission profile of ULAS J1120+0641 compared to those of two lower-redshift quasars.
Figure 4: Rest-frame transmission profile of ULAS J1120+0641 in the region of the Lyα emission line, compared to several damping profiles.

References

  1. Fan, X. et al. Constraining the evolution of the ionizing background and the epoch of reionization with z6 quasars. II. A sample of 19 quasars. Astron. J. 132, 117–136 (2006)

    Article  ADS  CAS  Google Scholar 

  2. Fan, X. et al. A survey of z>5.8 quasars in the Sloan Digital Sky Survey. I. discovery of three new quasars and the spatial density of luminous quasars at z6. Astron. J. 122, 2833–2849 (2001)

    Article  ADS  Google Scholar 

  3. Fan, X. et al. A survey of z>5.7 quasars in the Sloan Digital Sky Survey. II. Discovery of three additional quasars at z>6. Astron. J. 125, 1649–1659 (2003)

    Article  ADS  Google Scholar 

  4. Willott, C. J. et al. The Canada-France High-z Quasar Survey: nine new quasars and the luminosity function at redshift 6. Astron. J. 139, 906–918 (2010)

    Article  ADS  CAS  Google Scholar 

  5. Miralda-Escude, J. Reionization of the intergalactic medium and the damping wing of the Gunn-Peterson trough. Astrophys. J. 501, 15–22 (1998)

    Article  ADS  CAS  Google Scholar 

  6. Lawrence, A. et al. The UKIRT Infrared Deep Sky Survey (UKIDSS). Mon. Not. R. Astron. Soc. 379, 1599–1617 (2007)

    Article  ADS  Google Scholar 

  7. York, D. G. et al. The Sloan Digital Sky Survey: technical summary. Astron. J. 120, 1579–1587 (2000)

    Article  ADS  Google Scholar 

  8. Mortlock, D. J. et al. Probabilistic photometric quasar selection. Mon. Not. R. Astron. Soc. (in the press)

  9. Dunkley, J. et al. Five-year Wilkinson Microwave Anisotropy Probe observations: likelihoods and parameters from the WMAP data. Astrophys. J. Suppl. 180, 306–329 (2009)

  10. Lehnert, M. D. et al. Spectroscopic confirmation of a galaxy at redshift z 8.6. Nature 467, 940–942 (2010)

    Article  ADS  CAS  Google Scholar 

  11. Vanzella, E. et al. Spectroscopic confirmation of two Lyman break galaxies at redshift beyond 7. Astrophys. J. 730, L35–L40 (2011)

    Article  ADS  Google Scholar 

  12. Tanvir, N. R. et al. A γ-ray burst at a redshift of z 8.2. Nature 461, 1254–1257 (2009)

    Article  ADS  CAS  Google Scholar 

  13. Willott, C. J. et al. Eddington-limited accretion and the black hole mass function at redshift 6. Astron. J. 140, 546–560 (2010)

    Article  ADS  CAS  Google Scholar 

  14. Willott, C. J. et al. Four quasars above redshift 6 discovered by the Canada-France High-z Quasar Survey. Astron. J. 134, 2435–2450 (2007)

    Article  ADS  CAS  Google Scholar 

  15. Hewett, P. C. & Wild, V. Improved redshifts for SDSS quasar spectra. Mon. Not. R. Astron. Soc. 405, 2302–2316 (2010)

    ADS  CAS  Google Scholar 

  16. Richards, G. T. et al. Unification of luminous Type 1 quasars through C IV emission. Astron. J. 141, 167–182 (2011)

    Article  ADS  Google Scholar 

  17. Becker, R. H., White, R. L. & Helfand, D. J. The FIRST survey: faint images of the radio sky at twenty centimeters. Astrophys. J. 450, 559–577 (1995)

    Article  ADS  Google Scholar 

  18. Telfer, R. C., Zheng, W., Kriss, G. A. & Davidsen, A. F. The rest-frame extreme-ultraviolet spectral properties of quasi-stellar objects. Astrophys. J. 565, 773–785 (2002)

    Article  ADS  CAS  Google Scholar 

  19. Vestergaard, M. & Osmer, P. S. Mass functions of the active black holes in distant quasars from the Large Bright Quasar Survey, the Bright Quasar Survey, and the color-selected sample of the SDSS fall equatorial stripe. Astrophys. J. 699, 800–816 (2009)

    Article  ADS  CAS  Google Scholar 

  20. Volonteri, M. & Rees, M. J. Quasars at z 6: the survival of the fittest. Astrophys. J. 650, 669–678 (2006)

    Article  ADS  Google Scholar 

  21. Willott, C. J., McLure, R. J. & Jarvis, M. J. A 3×109M black hole in the quasar SDSS J1148+5251 at z 6.41. Astrophys. J. 587, L15–L18 (2003)

    Article  ADS  Google Scholar 

  22. Haiman, Z. The origin and detection of high-redshift supermassive black holes. AIP Conf. Ser. (eds Whalen, D. J., Bromm, V. & Yoshida, N. ) 1294, 215–224 (American Institute of Physics, 2010)

    Google Scholar 

  23. Carilli, C. L. et al. Ionization near zones associated with quasars at z6. Astrophys. J. 714, 834–839 (2010)

    Article  ADS  CAS  Google Scholar 

  24. Haiman, Z. The detectability of high-redshift Lyα emission lines prior to the reionization of the universe. Astrophys. J. 576, L1–L4 (2002)

    Article  ADS  Google Scholar 

  25. Bolton, J. S. & Haehnelt, M. G. The nature and evolution of the highly ionized near-zones in the absorption spectra of z 6 quasars. Mon. Not. R. Astron. Soc. 374, 493–514 (2007)

    Article  ADS  CAS  Google Scholar 

  26. Wyithe, J. S. B., Loeb, A. & Carilli, C. Improved constraints on the neutral intergalactic hydrogen surrounding quasars at redshifts z > 6. Astrophys. J. 628, 575–582 (2005)

    Article  ADS  CAS  Google Scholar 

  27. Mesinger, A. & Haiman, Z. Evidence of a cosmological Strömgren surface and of significant neutral hydrogen surrounding the quasar SDSS J1030+0524. Astrophys. J. 611, L69–L72 (2004)

    Article  ADS  CAS  Google Scholar 

  28. Calverley, A. P., Becker, G. D., Haehnelt, M. G. & Bolton, J. S. Measurements of the UV background at 4.6 < z < 6.4 using the quasar proximity effect. Mon. Not. R. Astron. Soc. 420, 1–10 (2010)

    Google Scholar 

  29. White, R. L., Becker, R. H., Fan, X. & Strauss, M. A. Probing the ionization state of the Universe at z>6. Astron. J. 126, 1–14 (2003)

    Article  ADS  CAS  Google Scholar 

  30. Gunn, J. E. & Peterson, B. A. On the density of neutral hydrogen in intergalactic space. Astrophys. J. 142, 1633–1641 (1965)

    Article  ADS  CAS  Google Scholar 

Download references

Acknowledgements

M.P. acknowledges support from the University of London’s Perren Fund. P.C.H. and R.G.McM. acknowledge support from the STFC-funded Galaxy Formation and Evolution programme at the Institute of Astronomy. X. Fan and R. White supplied spectra of the SDSS quasars. M. Haehnelt provided insights into quasar near-zone physics. The staffs of the Joint Astronomy Centre, the Cambridge Astronomical Survey Unit and the Wide-Field Astronomy Unit, Edinburgh, all made vital contributions to the UKIDSS project. The support staff at the Gemini North Telescope, particularly K. Roth, provided assistance with the Gemini observations. This work is based in part on data obtained from UKIDSS, SDSS, the Liverpool Telescope, the Isaac Newton Telescope, the Gemini Observatory and the European Southern Observatory.

Author information

Authors and Affiliations

Authors

Contributions

D.J.M., S.J.W., M.P., B.P.V., P.C.H., R.G.McM. and C.S. identified ULAS J1120+0641 and obtained the follow-up observations. S.J.W., P.C.H., D.J.M., T.T., B.P.V., R.G.McM. and M.P. analysed the follow-up observations and interpreted the results. A.A., S.D., E.A.G.-S., N.C.H., P.H., M.J.I. and A.L. obtained, analysed and disseminated the UKIDSS data. E.K. and H.J.A.R. obtained the FORS2 spectrum of ULAS J1120+0641. D.J.M. and S.J.W. wrote the manuscript, into which all other authors had input.

Corresponding author

Correspondence to Daniel J. Mortlock.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

PowerPoint slides

Rights and permissions

Reprints and permissions

About this article

Cite this article

Mortlock, D., Warren, S., Venemans, B. et al. A luminous quasar at a redshift of z = 7.085. Nature 474, 616–619 (2011). https://doi.org/10.1038/nature10159

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature10159

This article is cited by

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing