Letter | Published:

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

Nature volume 457, pages 699701 (05 February 2009) | Download Citation


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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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.

Author information


  1. Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg, Germany

    • Fabian Walter
    •  & Dominik Riechers
  2. California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, USA

    • Dominik Riechers
  3. Institut de Radio Astronomie Millimétrique, 300 rue de la Piscine, F-38406 St-Martin-d’Hères, France

    • Pierre Cox
    •  & Roberto Neri
  4. National Radio Astronomy Observatory, PO Box O, Socorro, New Mexico 87801, USA

    • Chris Carilli
  5. Argelander Institut für Astronomie, Auf dem Hügel 71, D-53121 Bonn, Germany

    • Frank Bertoldi
  6. Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn, Germany

    • Axel Weiss
  7. L’Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Roma, I-00040 Monte Porzio Catone, Roma, Italy

    • Roberto Maiolino


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Correspondence to Fabian Walter.

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