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Early star-forming galaxies and the reionization of the Universe


Star-forming galaxies trace cosmic history. Recent observational progress with the NASA Hubble Space Telescope has led to the discovery and study of the earliest known galaxies, which correspond to a period when the Universe was only 800 million years old. Intense ultraviolet radiation from these early galaxies probably induced a major event in cosmic history: the reionization of intergalactic hydrogen.

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Figure 1: Cosmic reionization.
Figure 2: Ionizing flux from high-redshift galaxies.
Figure 3: Distant star-forming galaxies and reionization.
Figure 4: Tracing the end of reionization with the Lyα line.


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We thank A. Klypin for the use of his cosmological simulation, and A. Loeb, A. Shapley and L. Hernquist for comments. B.E.R. acknowledges support from a Hubble Fellowship. R.S.E. acknowledges the hospitality of Leiden Observatory. J.S.D. acknowledges the support of the Royal Society through a Wolfson Research Merit award, and also the support of the European Research Council through the award of an Advanced Grant. R.J.M. acknowledges the support of the Royal Society through a University Research Fellowship. D.P.S. acknowledges financial support from an STFC postdoctoral research fellowship and a Schlumberger Research Fellowship at Darwin College.

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B.E.R. and R.S.E. wrote the main manuscript text. B.E.R. performed the calculations presented in Box 2 and Figs 13. J.S.D. and R.J.M. prepared and analysed the data presented in Box 3. D.P.S. prepared and analysed the data presented in Fig. 4. All authors reviewed, discussed and commented on the manuscript.

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Correspondence to Brant E. Robertson.

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

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