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| Paper: |
Lyman-Alpha Emitters in the Hierarchically Clustering Galaxy Formation |
| Volume: |
399, Panoramic Views of Galaxy Formation and Evolution |
| Page: |
32 |
| Authors: |
Kobayashi, M.A.R.; Totani, T.; Nagashima, M. |
| Abstract: |
We have constructed a new theoretical model for the luminosity functions (LFs) of Lyα emitters (LAEs) in the framework of hierarchical galaxy formation. We do not change the original model parameters, but instead introduce a physically motivated model to describe the escape fraction of Lyα photons from host galaxies (fLyαesc). Specifically, for the first time two new effects are incorporated on fLyαesc : extinction by interstellar dust and galaxy-scale outflow induced as star formation feedback. The new model reproduces well all the observed Lyα LFs of LAEs at z ∼ 3 − 6. Our model predicts that galaxies with strong outflows and fLyαesc ≈ 0.4 should dominate the observed LFs. On the other hand, we find that our model significantly over-predicts LAEs at z > 6, and absorption of Lyα photons by neutral hydrogen in the intergalactic medium (IGM) provides a reasonable interpretation for this discrepancy. This indicates that the IGM neutral fraction xHI rapidly evolves from xHI ≪ 1 at z < 6 to a value of order unity at z ∼ 6 − 7, which is broadly consistent with other observational constraints on the history of reionization. |
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