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arXiv · astro-ph/0604149

The End of the Reionization Epoch Probed by Ly-alpha Emitters at z=6.5 in the Subaru Deep Field

N. Kashikawa·K. Shimasaku·M. A. Malkan·M. Doi·Y. Matsuda·M. Ouchi·Y. Taniguchi·C. Ly·T. Nagao·M. Iye·K. Motohara·T. Murayama·K. Murozono·K. Nariai·K. Ohta·S. Okamura·T. Sasaki·Y. Shioya·M. Umemura
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Abstract

We report an extensive search for Lyman-alpha emitters (LAEs) at z=6.5 in the Subaru Deep Field. Subsequent spectroscopy with Subaru and Keck identified eight more LAEs, giving a total of 17 spectroscopically confirmed LAEs at z=6.5. Based on this spectroscopic sample of 17, complemented by a photometric sample of 58 LAEs, we have derived a more accurate Lyman-alpha luminosity function of LAEs at z=6.5, which reveals an apparent deficit at the bright end of ~0.75 mag fainter L*, compared with that observed at z=5.7. The difference in the LAE luminosity functions between z=5.7 and 6.5 is significant at the 3-sigma level, which is reduced to 2-sigma when cosmic variance is taken into account. This result may imply that the reionization of the universe has not been completed at z=6.5. We found that the spatial distribution of LAEs at z=6.5 was homogeneous over the field. We discuss the implications of these results for the reionization of the universe.

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N. Kashikawa, K. Shimasaku, M. A. Malkan, M. Doi, Y. Matsuda, M. Ouchi, Y. Taniguchi, C. Ly, T. Nagao, M. Iye, K. Motohara, T. Murayama, K. Murozono, K. Nariai, K. Ohta, S. Okamura, T. Sasaki, Y. Shioya, M. Umemura. 2006-07-22. The End of the Reionization Epoch Probed by Ly-alpha Emitters at z=6.5 in the Subaru Deep Field. https://doi.org/10.1086/504966

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