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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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.
The authors declare no competing financial interests.
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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). https://doi.org/10.1038/nature09527
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