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A kiloparsec-scale hyper-starburst in a quasar host less than 1 gigayear after the Big Bang


The host galaxy of the quasar SDSS J114816.64+525150.3 (at redshift z = 6.42, when the Universe was less than a billion years old) has an infrared luminosity of 2.2 × 1013 times that of the Sun1,2, presumably significantly powered by a massive burst of star formation3,4,5,6. In local examples of extremely luminous galaxies, such as Arp 220, the burst of star formation is concentrated in a relatively small central region of <100 pc radius7,8. It is not known on which scales stars are forming in active galaxies in the early Universe, at a time when they are probably undergoing their initial burst of star formation. We do know that at some early time, structures comparable to the spheroidal bulge of the Milky Way must have formed. Here we report a spatially resolved image of [C ii] emission of the host galaxy of J114816.64+525150.3 that demonstrates that its star-forming gas is distributed over a radius of about 750 pc around the centre. The surface density of the star formation rate averaged over this region is 1,000 year-1 kpc-2. This surface density is comparable to the peak in Arp 220, although about two orders of magnitude larger in area. This vigorous star-forming event is likely to give rise to a massive spheroidal component in this system.

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Figure 1: [C  ii ] observations of the z = 6.42 quasar J1148+5251 obtained with the IRAM Plateau de Bure interferometer.
Figure 2: Spatially integrated [C  ii ] spectrum of the z = 6.42 quasar J1148+5251.


  1. Bertoldi, F. et al. Dust and molecular emission from high-redshift quasars. Astron. Astrophys. 406, 55–58 (2003)

    Article  ADS  Google Scholar 

  2. Beelen, A. et al. 350 micron dust emission from high-redshift quasars. Astrophys. J. 642, 694–701 (2006)

    Article  ADS  CAS  Google Scholar 

  3. Walter, F. et al. Molecular gas in the host galaxy of a quasar at redshift z = 6.42. Nature 424, 406–408 (2003)

    Article  ADS  CAS  Google Scholar 

  4. Bertoldi, F. et al. High-excitation CO in a quasar host galaxy at z = 6.42. Astron. Astrophys. Lett. 409, 47–50 (2003)

    Article  ADS  Google Scholar 

  5. Maiolino, R. et al. First detection of [C ii] 158 µm at high redshift: vigorous star formation in the early universe. Astron. Astrophys. Lett. 440, 51–54 (2005)

    Article  ADS  Google Scholar 

  6. Carilli, C. et al. Radio continuum imaging of far-infrared-luminous QSOs at z &gt; 6. Astron. J. 128, 997–1001 (2004)

    Article  ADS  CAS  Google Scholar 

  7. Downes, D. & Solomon, P. Rotating nuclear rings and extreme starbursts in ultraluminous galaxies. Astrophys. J. 507, 615–654 (1999)

    Article  ADS  Google Scholar 

  8. Scoville, N. Z., Yun, M. S. & Bryant, P. M. Arcsecond imaging of CO emission in the nucleus of Arp 220. Astrophys. J. 484, 702–719 (1997)

    Article  ADS  CAS  Google Scholar 

  9. Tielens, A. G. G. M. & Hollenbach, D. Photodissociation regions. I. Basic model. II. A model for the Orion photodissociation region. Astrophys. J. 291, 722–754 (1985)

    Article  ADS  CAS  Google Scholar 

  10. Stacey, G. J. et al. The 158 micron forbidden C ii line—a measure of global star formation activity in galaxies. Astrophys. J. 373, 423–444 (1991)

    Article  ADS  CAS  Google Scholar 

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

    Article  ADS  Google Scholar 

  12. Fan, X. et al. Constraining the evolution of the ionizing background and the epoch of reionization with z 6 quasars. II. A sample of 19 quasars. Astron. J. 132, 117–136 (2006)

    Article  ADS  CAS  Google Scholar 

  13. Iono, D. et al. A detection of [C ii] line emission in the z = 4.7 QSO BR 1202–0725. Astrophys. J. Lett. 645, 97–100 (2006)

    Article  ADS  Google Scholar 

  14. Walter, F. et al. Resolved molecular gas in a quasar host galaxy at redshift z = 6.42. Astrophys. J. Lett. 615, 17–20 (2004)

    Article  ADS  Google Scholar 

  15. Spergel, D. N. et al. Three-year Wilkinson Microwave Anisotropy Probe (WMAP) observations: Implications for cosmology. Astrophys. J. 170 (Suppl.). 377–408 (2007)

    Article  Google Scholar 

  16. Wright, E. L. A cosmology calculator for the World Wide Web. Publ. Astron. Soc. Pacif. 118, 1711–1715 (2006)

    Article  ADS  Google Scholar 

  17. Riechers, D. A., Walter, F., Carilli, C. & Bertoldi, F. observations of dense molecular gas in a quasar host galaxy at z = 6.42: Further evidence for a nonlinear dense gas–star formation relation at early cosmic times. Astrophys. J. Lett. 671, 13–16 (2007)

    Article  ADS  Google Scholar 

  18. Omont, A. et al. A 1.2 mm MAMBO/IRAM-30 m survey of dust emission from the highest redshift PSS quasars. Astron. Astrophys. 374, 371–381 (2001)

    Article  ADS  Google Scholar 

  19. Werner, M. W. et al. One arc-minute resolution maps of the Orion Nebula at 20, 50, and 100 microns. Astrophys. J. 204, 420–426 (1976)

    Article  ADS  CAS  Google Scholar 

  20. Tacconi, L. et al. High-resolution millimeter imaging of submillimeter galaxies. Astrophys. J. 640, 228–240 (2006)

    Article  ADS  CAS  Google Scholar 

  21. Thompson, T., Quataert, E. & Murrey, N. Radiation pressure-supported starburst disks and active galactic nucleus fueling. Astrophys. J. 630, 167–185 (2005)

    Article  ADS  Google Scholar 

  22. Elmegreen, B. G. Galactic bulge formation as a maximum intensity starburst. Astrophys. J. 517, 103–107 (1999)

    Article  ADS  Google Scholar 

  23. Gao, Y. & Solomon, P. M. HCN survey of normal spiral, infrared–luminous, and ultraluminous galaxies. Astrophys. J. 152 (Suppl.). 63–80 (2004)

    Article  ADS  CAS  Google Scholar 

  24. Dekel, A. et al. Cold streams in early massive hot haloes as the main mode of galaxy formation. Nature 10.1038/nature07648 (in the press)

  25. Walter, F. & Carilli, C. Detecting the most distant (z &gt; 7) objects with ALMA. Astrophys. Space Sci. 313, 313–316 (2008)

    Article  ADS  CAS  Google Scholar 

  26. White, R. L., Becker, R. H., Fan, X. & Strauss, M. A. Hubble Space Telescope Advanced Camera for Surveys observations of the z = 6.42 quasar SDSS J1148+5251: A leak in the Gunn–Peterson trough. Astron. J. 129, 2102–2107 (2005)

    Article  ADS  CAS  Google Scholar 

  27. Solomon, P. M. & Vanden Bout, P. A. Molecular gas at high redshift. Annu. Rev. Astron. Astrophys. 43, 677–725 (2005)

    Article  ADS  CAS  Google Scholar 

  28. Malhotra, S. et al. Infrared Space Observatory measurements of [C ii] line variations in galaxies. Astrophys. J. 491, 27–30 (1997)

    Article  ADS  Google Scholar 

  29. Luhman, M. L. et al. Infrared Space Observatory measurements of a [C ii] 158 micron line deficit in ultraluminous infrared galaxies. Astrophys. J. Lett. 504, 11–15 (1998)

    Article  ADS  Google Scholar 

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This work is based on observations carried out with the IRAM Plateau de Bure Interferometer. IRAM is supported by MPG (Germany), INSU/CNRS (France) and IGN (Spain). D.R. acknowledges support from NASA through a Hubble Fellowship awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA. C.C. acknowledges support from the Max-Planck Gesellschaft and the Alexander von Humboldt Stiftung through the Max-Planck-Forschungspreis 2005. F.W. and D.R. appreciate the hospitality of the Aspen Center for Physics, where this manuscript was written.

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Correspondence to Fabian Walter.

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Walter, F., Riechers, D., Cox, P. et al. A kiloparsec-scale hyper-starburst in a quasar host less than 1 gigayear after the Big Bang. Nature 457, 699–701 (2009).

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