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Black hole growth in the early Universe is self-regulated and largely hidden from view


A Corrigendum to this article was published on 08 June 2017


The formation of the first massive objects in the infant Universe remains impossible to observe directly and yet it sets the stage for the subsequent evolution of galaxies1,2,3. Although some black holes with masses more than 109 times that of the Sun have been detected in luminous quasars less than one billion years after the Big Bang4,5, these individual extreme objects have limited utility in constraining the channels of formation of the earliest black holes; this is because the initial conditions of black hole seed properties are quickly erased during the growth process6. Here we report a measurement of the amount of black hole growth in galaxies at redshift z = 6–8 (0.95–0.7 billion years after the Big Bang), based on optimally stacked, archival X-ray observations. Our results imply that black holes grow in tandem with their host galaxies throughout cosmic history, starting from the earliest times. We find that most copiously accreting black holes at these epochs are buried in significant amounts of gas and dust that absorb most radiation except for the highest-energy X-rays. This suggests that black holes grew significantly more during these early bursts than was previously thought, but because of the obscuration of their ultraviolet emission they did not contribute to the re-ionization of the Universe.

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Figure 1: Accreted black hole mass density as a function of redshift.
Figure 2: Cumulative number of sources as a function of redshift for individual X-ray detections.

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  1. Silk, J. & Rees, M. J. Quasars and galaxy formation. Astron. Astrophys. 331, L1–L4 (1998)

    ADS  Google Scholar 

  2. Barkana, R. & Loeb, A. In the beginning: the first sources of light and the reionization of the universe. Phys. Rep. 349, 125–238 (2001)

    Article  CAS  ADS  Google Scholar 

  3. Volonteri, M., Haardt, F. & Madau, P. The assembly and merging history of supermassive black holes in hierarchical models of galaxy formation. Astrophys. J. 582, 559–573 (2003)

    Article  ADS  Google Scholar 

  4. Fan, X. et al. High-redshift quasars found in Sloan Digital Sky Survey commissioning data. IV. Luminosity function from the fall equatorial stripe sample. Astron. J. 121, 54–65 (2001)

    Article  ADS  Google Scholar 

  5. 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  CAS  ADS  Google Scholar 

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

    Article  ADS  Google Scholar 

  7. Brandt, W. N. & Hasinger, G. Deep extragalactic X-ray surveys. Annu. Rev. Astron. Astrophys. 43, 827–859 (2005)

    Article  ADS  Google Scholar 

  8. Lawrence, A. & Elvis, M. Obscuration and the various kinds of Seyfert galaxies. Astrophys. J. 256, 410–426 (1982)

    Article  CAS  ADS  Google Scholar 

  9. Shemmer, O. et al. Chandra observations of the highest redshift quasars from the Sloan Digital Sky Survey. Astrophys. J. 644, 86–99 (2006)

    Article  ADS  Google Scholar 

  10. Bouwens, R. J., Illingworth, G. D., Blakeslee, J. P. & Franx, M. Galaxies at z6: the UV luminosity function and luminosity density from 506 HUDF, HUDF Parallel ACS Field, and GOODS i-dropouts. Astrophys. J. 653, 53–85 (2006)

    Article  CAS  ADS  Google Scholar 

  11. Bouwens, R. J. et al. UV luminosity functions from 113 z7 and z8 Lyman-break galaxies in the ultra-deep HUDF09 and wide-area ERS WFC3/IR observations. Preprint at 〈〉 (2010)

  12. Bouwens, R. J. et al. Discovery of z8 galaxies in the Hubble Ultra Deep Field from ultra-deep WFC3/IR observations. Astrophys. J. 709, L133–L137 (2010)

    Article  CAS  ADS  Google Scholar 

  13. Labbé, I., Bouwens, R., Illingworth, G. D. & Franx, M. Spitzer IRAC confirmation of z850-dropout galaxies in the Hubble Ultra Deep Field: stellar masses and ages at z7. Astrophys. J. 649, L67–L70 (2006)

    Article  ADS  Google Scholar 

  14. Ueda, Y. et al. Suzaku observations of active galactic nuclei detected in the Swift BAT survey: discovery of a “new type” of buried supermassive black holes. Astrophys. J. 664, L79–L82 (2007)

    Article  CAS  ADS  Google Scholar 

  15. Sazonov, S., Revnivtsev, M., Krivonos, R., Churazov, E. & Sunyaev, R. Hard X-ray luminosity function and absorption distribution of nearby AGN: INTEGRAL all-sky survey. Astron. Astrophys. 462, 57–66 (2007)

    Article  CAS  ADS  Google Scholar 

  16. Loeb, A. The race between stars and quasars in reionizing cosmic hydrogen. J. Cosmol. Astropart. Phys. 3, 022 (2009)

    Article  ADS  Google Scholar 

  17. Treister, E., Urry, C. M. & Virani, S. The space density of Compton thick AGN and the X-ray background. Astrophys. J. 696, 110–120 (2009)

    Article  CAS  ADS  Google Scholar 

  18. 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  CAS  ADS  Google Scholar 

  19. Treister, E. et al. Major galaxy mergers and the growth of supermassive black holes in quasars. Science 328, 600–602 (2010)

    Article  CAS  ADS  Google Scholar 

  20. Ferrarese, L. & Merritt, D. A fundamental relation between supermassive black holes and their host galaxies. Astrophys. J. 539, L9–L12 (2000)

    Article  ADS  Google Scholar 

  21. Gebhardt, K. et al. A relationship between nuclear black hole mass and galaxy velocity dispersion. Astrophys. J. 539, L13–L16 (2000)

    Article  ADS  Google Scholar 

  22. King, A. Black holes, galaxy formation, and the MBH-σ relation. Astrophys. J. 596, L27–L29 (2003)

    Article  ADS  Google Scholar 

  23. Wyithe, J. S. B. & Loeb, A. Self-regulated growth of supermassive black holes in galaxies as the origin of the optical and X-ray luminosity functions of quasars. Astrophys. J. 595, 614–623 (2003)

    Article  ADS  Google Scholar 

  24. Hopkins, P. F. et al. A unified, merger-driven model of the origin of starbursts, quasars, the cosmic X-ray background, supermassive black holes, and galaxy spheroids. Astrophys. J. 163, 1–49 (2006)

    Article  CAS  Google Scholar 

  25. Madau, P. & Rees, M. J. Massive black holes as population III remnants. Astrophys. J. 551, L27–L30 (2001)

    Article  ADS  Google Scholar 

  26. Bromm, V. & Loeb, A. Formation of the first supermassive black holes. Astrophys. J. 596, 34–46 (2003)

    Article  ADS  Google Scholar 

  27. Lodato, G. & Natarajan, P. Supermassive black hole formation during the assembly of pregalactic discs. Mon. Not. R. Astron. Soc. 371, 1813–1823 (2006)

    Article  ADS  Google Scholar 

  28. Shankar, F., Weinberg, D. H. & Miralda-Escudé, J. Self-consistent models of the AGN and black hole populations: duty cycles, accretion rates, and the mean radiative efficiency. Astrophys. J. 690, 20–41 (2009)

    Article  CAS  ADS  Google Scholar 

  29. Treister, E., Urry, C. M., Schawinski, K., Cardamone, C. N. & Sanders, D. B. Heavily obscured active galactic nuclei in high-redshift luminous infrared galaxies. Astrophys. J. 722, L238–L243 (2010)

    Article  ADS  Google Scholar 

  30. Volonteri, M. Formation of supermassive black holes. Astron. Astrophys. Rev. 18, 279–315 (2010)

    Article  ADS  Google Scholar 

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We thank T. Goto, M. Urry and D. Sanders for conversations. Support for the work of E.T. and K.S. was provided by NASA through Chandra/Einstein Post-doctoral Fellowship Awards. M.V. acknowledges support from the Smithsonian Astrophysical Observatory. P.N. acknowledges support via a Guggenheim Fellowship from the John Simon Guggenheim Foundation. The work of E.G. was partially funded by the NSF.

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Authors and Affiliations



E.T. started the project, collected the galaxy samples, performed the X-ray stacking calculations and wrote the majority of the text. K.S. helped to collect the galaxy sample studied here, and contributed to the conception of the project and the analysis and interpretation of the results. M.V. and P.N. created the black hole growth models, computed the contribution of these sources to the re-ionization of the Universe and contributed extensively to the theoretical interpretation of the observational results. E.G. developed the optimal X-ray stacking formalism and worked with E.T. to implement it on these data. All authors discussed the results and contributed to the writing of the manuscript.

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Correspondence to Ezequiel Treister.

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The authors declare no competing financial interests.

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Treister, E., Schawinski, K., Volonteri, M. et al. Black hole growth in the early Universe is self-regulated and largely hidden from view. Nature 474, 356–358 (2011).

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