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Paper: Exploring Galaxy Formation and Reionization Towards the Cosmic Dawn
Volume: 393, New Horizons in Astronomy: Frank N. Bash Symposium 2007
Page: 127
Authors: Ouchi, M.
Abstract: I review observational studies of galaxies at z ∼ 4 − 10. Recent deep surveys push the limit of large telescopes, and aim to accomplish two major goals: (i) characterizing galaxy evolution in the cosmic time and (ii) understanding the history of reionization. Luminosity functions (LFs) of dropout galaxies and Lyα emitters (LAEs) indicate that a very young Lyα emitting population emerges at z ∼ 6, while a number of post-starburst galaxies already exist at this epoch. The combination of theoretical models, LFs, and correlation functions of LAEs places upper limits on neutral fraction of inter-galactic medium which do not prefer beginning of reionization at z = 6 − 7 but a moderate change of neutral hydrogen from z = 6 to 7. Ambitious on-going projects search for galaxies beyond the current observational limit of z = 7 in blank and nearby-cluster fields. These on-going searches not only extend the investigations of galaxies at z = 3 − 7, but also become precursors of future studies that address questions about reionization history and first-generation stars at z ∼ 10 − 20 with the upcoming very large telescopes, i.e., JWST and ELTs, in the 2010s.
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