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| Paper: |
The End of the Reionization Epoch Probed by Lyα Emitters at z = 6.5 |
| Volume: |
380, At the Edge of the Universe: Latest Results from the Deepest Astronomical Surveys |
| Page: |
11 |
| Authors: |
Kashikawa, N. |
| Abstract: |
We report our extensive search for Lyα emitters (LAEs) at z = 6.5 in the Subaru Deep Field (SDF). We carried out spectroscopic observations with Subaru/Keck to identify LAEs that were selected by narrow-band excess at 920nm. Now we have 17 spectroscopically confirmed LAEs at z = 6.5. Based on this spectroscopic sample, complemented by a photometric sample of 58 LAEs, we have derived a more accurate Lyα luminosity function (LF) of LAEs at z = 6.5, which reveals an apparent deficit at the bright end, with L being ~ 0.75 mag fainter than that observed at z = 5.7. The difference has 3σ significance, which is reduced to 2σ when cosmic variance is taken into account. The decline of the Lyα LF implies the cosmic neutral fraction xHI = 0.45 based on a theoretical IGM model, although this predicted value is strongly model dependent. The LF of the rest-frame UV continuum of the LAE sample at z = 6.5, which is not sensitivive to the neutral IGM, is almost consistent with that of LAEs at z = 5.7 and i-dropouts at z ~ 6, even at their bright ends. This result may imply that the reionization of the universe has not been completed at z = 6.5. |
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