A dust-obscured massive maximum-starburst galaxy at a redshift of 6.34

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Massive present-day early-type (elliptical and lenticular) galaxies probably gained the bulk of their stellar mass and heavy elements through intense, dust-enshrouded starbursts—that is, increased rates of star formation—in the most massive dark-matter haloes at early epochs. However, it remains unknown how soon after the Big Bang massive starburst progenitors exist. The measured redshift (z) distribution of dusty, massive starbursts has long been suspected to be biased low in z owing to selection effects1, as confirmed by recent findings of systems with redshifts as high as 5 (refs 2–4). Here we report the identification of a massive starburst galaxy at z = 6.34 through a submillimetre colour-selection technique. We unambiguously determined the redshift from a suite of molecular and atomic fine-structure cooling lines. These measurements reveal a hundred billion solar masses of highly excited, chemically evolved interstellar medium in this galaxy, which constitutes at least 40 per cent of the baryonic mass. A ‘maximum starburst’ converts the gas into stars at a rate more than 2,000 times that of the Milky Way, a rate among the highest observed at any epoch. Despite the overall downturn in cosmic star formation towards the highest redshifts5, it seems that environments mature enough to form the most massive, intense starbursts existed at least as early as 880 million years after the Big Bang.

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Figure 1: Redshift identification through molecular and atomic spectroscopy of HFLS 3.
Figure 2: Spectral energy distribution and Herschel/SPIRE colours of HFLS 3.
Figure 3: Gas dynamics, dust obscuration, and distribution of gas and star formation in HFLS 3.


  1. 1

    Chapman, S. C. et al. A median redshift of 2.4 for galaxies bright at submillimetre wavelengths. Nature 422, 695–698 (2003)

  2. 2

    Capak, P. et al. A massive protocluster of galaxies at a redshift of z ≈ 5.3. Nature 470, 233–235 (2011)

  3. 3

    Walter, F. et al. The intense starburst HDF 850.1 in a galaxy overdensity at z ≈ 5.2 in the Hubble Deep Field. Nature 486, 233–236 (2012)

  4. 4

    Vieira, J. D. et al. Dusty starburst galaxies in the early Universe as revealed by gravitational lensing. Nature 495, 344–347 (2013)

  5. 5

    Bouwens, R. et al. A candidate redshift z ≈ 10 galaxy and rapid changes in that population at an age of 500 Myr. Nature 469, 504–507 (2011)

  6. 6

    Oliver, S. et al. The Herschel Multi-tiered Extragalactic Survey: HerMES. Mon. Not. R. Astron. Soc. 424, 1614–1635 (2012)

  7. 7

    Béthermin, M. et al. A unified empirical model for infrared galaxy counts based on the observed physical evolution of distant galaxies. Astrophys. J. 757, L23 (2012)

  8. 8

    Karim, A. et al. An ALMA survey of submillimetre galaxies in the Extended Chandra Deep Field South: high resolution 870µm source counts. Mon. Not. R. Astron. Soc.. (in the press); preprint at http://arxiv.org/abs/1210.0249 (2012)

  9. 9

    Bouwens, R. J. et al. Galaxies at z 6: the UV luminosity function and luminosity density from 506 HUDF, HUDF parallel ACS field, and GOODS i-dropouts. Astrophys. J. 653, 53–85 (2006)

  10. 10

    Robertson, B. et al. Early star-forming galaxies and the reionization of the Universe. Nature 468, 49–55 (2010)

  11. 11

    Michałowski, M. J. et al. Rapid dust production in submillimeter galaxies at z > 4? Astrophys. J. 712, 942–950 (2010)

  12. 12

    Riechers, D. A. et al. Extended cold molecular gas reservoirs in z 3.4 submillimeter galaxies. Astrophys. J. 739, L31 (2011)

  13. 13

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

  14. 14

    Lagos, C. & Del P et al. On the impact of empirical and theoretical star formation laws on galaxy formation. Mon. Not. R. Astron. Soc. 416, 1566–1584 (2011)

  15. 15

    Tacconi, L. J. et al. Submillimeter galaxies at z 2: evidence for major mergers and constraints on lifetimes, IMF, and CO-H2 conversion factor. Astrophys. J. 680, 246–262 (2008)

  16. 16

    Tacconi, L. J. et al. High molecular gas fractions in normal massive star-forming galaxies in the young Universe. Nature 463, 781–784 (2010)

  17. 17

    Overzier, R. et al. ΛCDM predictions for galaxy protoclusters – I. The relation between galaxies, protoclusters and quasars at z 6. Mon. Not. R. Astron. Soc. 394, 577–594 (2009)

  18. 18

    Krumholz, M. R. et al. A universal, local star formation law in galactic clouds, nearby galaxies, high-redshift disks, and starbursts. Astrophys. J. 745, 69 (2012)

  19. 19

    Stacey, G. J. et al. A 158 μm [C II] line survey of galaxies at z 1–2: an indicator of star formation in the early universe. Astrophys. J. 724, 957–974 (2010)

  20. 20

    Rangwala, N. et al. Observations of Arp 220 using Herschel-SPIRE: an unprecedented view of the molecular gas in an extreme star formation environment. Astrophys. J. 743, 94 (2011)

  21. 21

    Gonzalez-Alfonso, E. et al. Herschel/PACS spectroscopy of NGC 4418 and Arp 220: H2O, H218O, OH, 18OH, O I, HCN and NH3 . Astron. Astrophys. 541, A4 (2012)

  22. 22

    van der Werf, P. et al. Water vapor emission reveals a highly obscured, star-forming nuclear region in the QSO host galaxy APM 08279+5255 at z = 3.9. Astrophys. J. 741, L38 (2011)

  23. 23

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

  24. 24

    Thompson, T. et al. Radiation pressure-supported starburst disks and active galactic nucleus fueling. Astrophys. J. 630, 167–185 (2005)

  25. 25

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

  26. 26

    Jiang, L. et al. A survey of z 6 quasars in the Sloan Digital Sky Survey deep stripe. II. Discovery of six quasars at zAB>21. Astron. J. 138, 305–311 (2009)

  27. 27

    Downes, D. & Solomon, P. M. Rotating nuclear rings and extreme starbursts in ultraluminous galaxies. Astrophys. J. 507, 615–654 (1998)

  28. 28

    Sodroski, T. J. et al. Large-scale characteristics of interstellar dust from COBE DIRBE observations. Astrophys. J. 428, 638–646 (1994)

  29. 29

    Murray, N. & Rahman, M. Star formation in massive clusters via the Wilkinson Microwave Anisotropy Probe and the Spitzer Glimpse survey. Astrophys. J. 709, 424–435 (2010)

  30. 30

    McMillan, P. J. Mass models of the Milky Way. Mon. Not. R. Astron. Soc. 414, 2446–2457 (2011)

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Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA. This research has made use of data from the HerMES project. HerMES is a Herschel Key Programme using guaranteed time from the SPIRE instrument team, ESAC scientists and a mission scientist. See Supplementary Information for further acknowledgements.

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D.A.R. had the overall lead of the project. C.M.B., D.L.C., I.P.-F., R.J.I., C.B., H.F., J.D.V. and R.N. contributed significantly to the taking and analysis of the follow-up data with different instruments by leading several telescope proposals and analysis efforts. C.D.D. led the selection of the parent sample. A. Conley, J.W., J.C., A. Cooray, P.H. and J.K. contributed significantly to the data analysis and to fitting and modelling the results. All other authors contributed to the proposals, source selection, data analysis and interpretation, in particular through work on the primary Herschel SPIRE data in which the source was discovered through the HerMES consortium (led by J.B. and S.J.O.). All authors have reviewed, discussed, and commented on the manuscript.

Correspondence to Dominik A. Riechers.

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Supplementary Information

This file contains Supplementary Text and Data 1-5, Supplementary Tables 1-4, Supplementary Figures 1-6 and additional references and acknowledgements. (PDF 3209 kb)

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Riechers, D., Bradford, C., Clements, D. et al. A dust-obscured massive maximum-starburst galaxy at a redshift of 6.34. Nature 496, 329–333 (2013) doi:10.1038/nature12050

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