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The formation and assembly of a typical star-forming galaxy at redshift z ≈ 3


Recent studies of galaxies 2–3 Gyr after the Big Bang have revealed large, rotating disks, similar to those of galaxies today1,2. The existence of well-ordered rotation in galaxies during this peak epoch of cosmic star formation indicates that gas accretion is likely to be the dominant mode by which galaxies grow, because major mergers of galaxies would completely disrupt the observed velocity fields. But poor spatial resolution and sensitivity have hampered this interpretation; such studies have been limited to the largest and most luminous galaxies, which may have fundamentally different modes of assembly from those of more typical galaxies (which are thought to grow into the spheroidal components at the centres of galaxies similar to the Milky Way). Here we report observations of a typical star-forming galaxy at z = 3.07, with a linear resolution of 100 parsecs. We find a well-ordered compact source in which molecular gas is being converted efficiently into stars, likely to be assembling a spheroidal bulge similar to those seen in spiral galaxies at the present day. The presence of undisrupted rotation may indicate that galaxies such as the Milky Way gain much of their mass by accretion rather than major mergers.

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Figure 1: Colour image of J2135-0102, a z = 3.07 galaxy magnified 28 ± 3 times into a near-complete Einstein ring8.
Figure 2: The internal dynamics of J2135-0102, reconstructed in the source plane with the use of the well-constrained lens model12.

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  1. Genzel, R. et al. The rapid formation of a large rotating disk galaxy three billion years after the Big Bang. Nature 442, 786–789 (2006)

    Article  ADS  CAS  Google Scholar 

  2. Forster-Schreiber, N. M. et al. SINFONI integral field spectroscopy of z  2 UV-selected galaxies. Astrophys. J. 645, 1062–1075 (2006)

    Article  ADS  Google Scholar 

  3. Law, D. et al. Integral field spectroscopy of high redshift star-forming galaxies with laser-guide star adaptive optics. Astrophys. J. 669, 929–946 (2007)

    Article  ADS  CAS  Google Scholar 

  4. Nesvadba, N. P. H. et al. Lyman break galaxies under a microscope: the small-scale dynamics and mass of an arc in the cluster 1E 0657-56. Astrophys. J. 650, 661–668 (2006)

    Article  ADS  CAS  Google Scholar 

  5. Ellis, R. S., Santos, M. R., Kneib, J.-P. & Kuijken, K. A faint star-forming system viewed through the lensing cluster Abell 2218: first light at z = 5.6? Astrophys. J. 560, 119–122 (2001)

    Article  ADS  Google Scholar 

  6. Kneib, J.-P., Ellis, R. S., Santos, M. R. & Richard, J. A probable z 7 galaxy strongly lensed by the rich cluster A2218: exploring the dark ages. Astrophys. J. 607, 697–703 (2004)

    Article  ADS  CAS  Google Scholar 

  7. Swinbank, M. et al. Resolved spectroscopy of a gravitationally lensed L* Lyman-break galaxy at z 5. Mon. Not. R. Astron. Soc. 376, 479–491 (2007)

    Article  ADS  CAS  Google Scholar 

  8. Smail, I. et al. A very bright highly magnified Lyman break galaxy at z = 3.07. Astrophys. J. 654, L33–L36 (2007)

    Article  ADS  CAS  Google Scholar 

  9. Dye, S., Smail, I., Swinbank, A. M., Ebeling, H. & Edge, A. C. Separation of the visible and dark matter in the Einstein ring LBG J213512.73-010143. Mon. Not. R. Astron. Soc. 379, 308–316 (2007)

    Article  ADS  Google Scholar 

  10. Larkin, J. et al. OSIRIS: a diffraction limited integral field spectrograph for Keck. N. Astron. Rev. 50, 362–364 (2006)

    Article  ADS  Google Scholar 

  11. Bouwens, R. J., Illingworth, G. D., Blakeslee, J. P., Broadhurst, T. J. & Franx, M. Galaxy size evolution at high redshift and surface brightness selection effects. Astrophys. J. 611, L1–L4 (2004)

    Article  ADS  Google Scholar 

  12. Abraham, R. et al. The star formation history of the Hubble sequence: spatially resolved colour distributions of intermediate-redshift galaxies in the Hubble Deep Field. Mon. Not. R. Astron. Soc. 279, L47–L52 (1996)

    Article  ADS  Google Scholar 

  13. Coppin, K. E. K. et al. A detailed study of gas and star formation in a highly magnified Lyman break galaxy at z = 3.07. Astrophys. J. 665, 936–943 (2007)

    Article  ADS  CAS  Google Scholar 

  14. Kennicutt, R. C. Star formation along the Hubble Sequence. Annu. Rev. Astron. Astrophys. 36, 189–232 (1998)

    Article  ADS  CAS  Google Scholar 

  15. Erb, D. et al. α observations of a large sample of galaxies at z 2. Astrophys. J. 647, 128–139 (2006)

    Article  ADS  CAS  Google Scholar 

  16. Shapley, A. et al. The rest-frame optical properties of z 3 galaxies. Astrophys. J. 562, 95–123 (2001)

    Article  ADS  CAS  Google Scholar 

  17. Heckman, T. M. Galactic superwinds circa 2001. ASP Conference Proc. 254, 292–304 (2002)

    ADS  Google Scholar 

  18. Pettini, M. & Pagel, B. [O III]/[NII] as an abundance indicator at high redshift. Mon. Not. R. Astron. Soc. 348, L59–L63 (2004)

    Article  ADS  CAS  Google Scholar 

  19. Pilyugin, L. S. & Thuan, T. X. Oxygen abundance determination in H II regions: the strong line intensities–abundance calibration revisited. Astrophys. J. 631, 231–243 (2005)

    Article  ADS  CAS  Google Scholar 

  20. 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 

  21. Solomon, P. M., Downes, D., Radford, S. J. E. & Barrett, J. W. The molecular interstellar medium in ultraluminous infrared galaxies. Astrophys. J. 478, 144–161 (1997)

    Article  ADS  CAS  Google Scholar 

  22. Tacconi, L. 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)

    Article  ADS  CAS  Google Scholar 

  23. Erb, D. K. et al. The stellar, gas, and dynamical masses of star-forming galaxies at z 2. Astrophys. J. 646, 107–132 (2006)

    Article  ADS  CAS  Google Scholar 

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We thank J. Lyke for assistance with the Keck observations, and R. Bower, K. Coppin, M. Lehnert, R. Genzel, D. Erb, D. Law, A. Shapley, A. Jenkins, P. Salucci and T. Theuns for discussions. The OSIRIS data were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership between the California Institute of Technology, the University of California and NASA. The observatory was made possible by the financial support of the W. M. Keck Foundation. The SINFONI data are based on observations made with the ESO Telescopes at the Paranal Observatories. A.M.S. acknowledges financial support from STFC, and I.R.S. and R.S.E. acknowledge financial support from the Royal Society.

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Correspondence to Daniel P. Stark.

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Stark, D., Swinbank, A., Ellis, R. et al. The formation and assembly of a typical star-forming galaxy at redshift z ≈ 3. Nature 455, 775–777 (2008).

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