Census of Lyα Emission from ∼600 Galaxies at z = 5–14: Evolution of the Lyα Luminosity Function and a Late Sharp Cosmic Reionization
We present the statistical properties of Ly α emission in 586 galaxies at z = 4.5–14.2, observed by multiple JWST/NIRSpec spectroscopy projects, including the JADES, GLASS, CEERS, and GO/DDT programs. We obtain Ly α equivalent width (EW), Ly α escape fraction, and ionizing photon production efficie...
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IOP Publishing
2025-01-01
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| Online Access: | https://doi.org/10.3847/1538-4365/adc690 |
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| author | Yuta Kageura Masami Ouchi Minami Nakane Hiroya Umeda Yuichi Harikane Shintaro Yoshiura Kimihiko Nakajima Hidenobu Yajima Tran Thi Thai |
| author_facet | Yuta Kageura Masami Ouchi Minami Nakane Hiroya Umeda Yuichi Harikane Shintaro Yoshiura Kimihiko Nakajima Hidenobu Yajima Tran Thi Thai |
| author_sort | Yuta Kageura |
| collection | DOAJ |
| description | We present the statistical properties of Ly α emission in 586 galaxies at z = 4.5–14.2, observed by multiple JWST/NIRSpec spectroscopy projects, including the JADES, GLASS, CEERS, and GO/DDT programs. We obtain Ly α equivalent width (EW), Ly α escape fraction, and ionizing photon production efficiency measurements or upper limits for these galaxies, and confirm that the Ly α -emitting galaxy fraction decreases toward higher redshifts. We derive Ly α luminosity functions from z ∼ 5 to z ∼ 10–14 with the observed Ly α EW distributions and galaxy UV luminosity functions, and find an ∼3 dex decrease in number density at L _Ly _α = 10 ^42 –10 ^43 erg s ^−1 over the redshift range. Notably, this study presents the first constraints on the Ly α luminosity function at z ∼ 8–14. We obtain the neutral hydrogen fractions of ${x}_{{\rm{H}}\,{\rm\small{I}}}=0.1{7}_{-0.16}^{+0.23}$ , $0.6{3}_{-0.28}^{+0.18}$ , $0.7{9}_{-0.21}^{+0.13}$ , and $0.8{8}_{-0.13}^{+0.11}$ at z ∼ 6, 7, 8–9, and 10–14, respectively, via comparisons of the reionization models developed by seminumerical simulations with 21cmFAST explaining the observations of Ly α , UV continuum, and Planck electron optical depth. The high x _H I values over z ∼ 7–14 suggest a late and sharp reionization, with the primary reionization process occurring at z ∼ 6–7. Such a late and sharp reionization is not easily explained by either a clumpy intergalactic medium or sources of reionization in a classical faint-galaxy or a bright-galaxy/active galactic nucleus (AGN) scenario, unless a very high escape fraction or AGN duty cycle is assumed at z ∼ 6–7. |
| format | Article |
| id | doaj-art-101dd6e3fb4548b79024f1988e4ce1d4 |
| institution | DOAJ |
| issn | 0067-0049 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | The Astrophysical Journal Supplement Series |
| spelling | doaj-art-101dd6e3fb4548b79024f1988e4ce1d42025-08-20T03:10:11ZengIOP PublishingThe Astrophysical Journal Supplement Series0067-00492025-01-0127823310.3847/1538-4365/adc690Census of Lyα Emission from ∼600 Galaxies at z = 5–14: Evolution of the Lyα Luminosity Function and a Late Sharp Cosmic ReionizationYuta Kageura0https://orcid.org/0009-0004-0381-7216Masami Ouchi1https://orcid.org/0000-0002-1049-6658Minami Nakane2https://orcid.org/0009-0000-1999-5472Hiroya Umeda3https://orcid.org/0009-0008-0167-5129Yuichi Harikane4https://orcid.org/0000-0002-6047-430XShintaro Yoshiura5https://orcid.org/0000-0003-0581-5973Kimihiko Nakajima6https://orcid.org/0000-0003-2965-5070Hidenobu Yajima7https://orcid.org/0000-0002-1319-3433Tran Thi Thai8https://orcid.org/0000-0002-8408-4816Institute for Cosmic Ray Research, The University of Tokyo , 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8582, Japan ; kageura@icrr.u-tokyo.ac.jp; Department of Physics, Graduate School of Science, The University of Tokyo , 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, JapanInstitute for Cosmic Ray Research, The University of Tokyo , 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8582, Japan ; kageura@icrr.u-tokyo.ac.jp; National Astronomical Observatory of Japan , 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; Department of Astronomical Science, SOKENDAI (The Graduate University for Advanced Studies) , Osawa 2-21-1, Mitaka, Tokyo, 181-8588, Japan; Kavli Institute for the Physics and Mathematics of the Universe (WPI), University of Tokyo , Kashiwa, Chiba 277-8583, JapanInstitute for Cosmic Ray Research, The University of Tokyo , 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8582, Japan ; kageura@icrr.u-tokyo.ac.jp; Department of Physics, Graduate School of Science, The University of Tokyo , 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, JapanInstitute for Cosmic Ray Research, The University of Tokyo , 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8582, Japan ; kageura@icrr.u-tokyo.ac.jp; Department of Physics, Graduate School of Science, The University of Tokyo , 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, JapanInstitute for Cosmic Ray Research, The University of Tokyo , 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8582, Japan ; kageura@icrr.u-tokyo.ac.jpNational Astronomical Observatory of Japan , 2-21-1 Osawa, Mitaka, Tokyo 181-8588, JapanNational Astronomical Observatory of Japan , 2-21-1 Osawa, Mitaka, Tokyo 181-8588, JapanCenter for Computational Sciences, University of Tsukuba , Ten-nodai, 1-1-1 Tsukuba, Ibaraki 305-8577, JapanNational Astronomical Observatory of Japan , 2-21-1 Osawa, Mitaka, Tokyo 181-8588, JapanWe present the statistical properties of Ly α emission in 586 galaxies at z = 4.5–14.2, observed by multiple JWST/NIRSpec spectroscopy projects, including the JADES, GLASS, CEERS, and GO/DDT programs. We obtain Ly α equivalent width (EW), Ly α escape fraction, and ionizing photon production efficiency measurements or upper limits for these galaxies, and confirm that the Ly α -emitting galaxy fraction decreases toward higher redshifts. We derive Ly α luminosity functions from z ∼ 5 to z ∼ 10–14 with the observed Ly α EW distributions and galaxy UV luminosity functions, and find an ∼3 dex decrease in number density at L _Ly _α = 10 ^42 –10 ^43 erg s ^−1 over the redshift range. Notably, this study presents the first constraints on the Ly α luminosity function at z ∼ 8–14. We obtain the neutral hydrogen fractions of ${x}_{{\rm{H}}\,{\rm\small{I}}}=0.1{7}_{-0.16}^{+0.23}$ , $0.6{3}_{-0.28}^{+0.18}$ , $0.7{9}_{-0.21}^{+0.13}$ , and $0.8{8}_{-0.13}^{+0.11}$ at z ∼ 6, 7, 8–9, and 10–14, respectively, via comparisons of the reionization models developed by seminumerical simulations with 21cmFAST explaining the observations of Ly α , UV continuum, and Planck electron optical depth. The high x _H I values over z ∼ 7–14 suggest a late and sharp reionization, with the primary reionization process occurring at z ∼ 6–7. Such a late and sharp reionization is not easily explained by either a clumpy intergalactic medium or sources of reionization in a classical faint-galaxy or a bright-galaxy/active galactic nucleus (AGN) scenario, unless a very high escape fraction or AGN duty cycle is assumed at z ∼ 6–7.https://doi.org/10.3847/1538-4365/adc690Galaxy evolutionHigh-redshift galaxiesLyα galaxiesReionization |
| spellingShingle | Yuta Kageura Masami Ouchi Minami Nakane Hiroya Umeda Yuichi Harikane Shintaro Yoshiura Kimihiko Nakajima Hidenobu Yajima Tran Thi Thai Census of Lyα Emission from ∼600 Galaxies at z = 5–14: Evolution of the Lyα Luminosity Function and a Late Sharp Cosmic Reionization The Astrophysical Journal Supplement Series Galaxy evolution High-redshift galaxies Lyα galaxies Reionization |
| title | Census of Lyα Emission from ∼600 Galaxies at z = 5–14: Evolution of the Lyα Luminosity Function and a Late Sharp Cosmic Reionization |
| title_full | Census of Lyα Emission from ∼600 Galaxies at z = 5–14: Evolution of the Lyα Luminosity Function and a Late Sharp Cosmic Reionization |
| title_fullStr | Census of Lyα Emission from ∼600 Galaxies at z = 5–14: Evolution of the Lyα Luminosity Function and a Late Sharp Cosmic Reionization |
| title_full_unstemmed | Census of Lyα Emission from ∼600 Galaxies at z = 5–14: Evolution of the Lyα Luminosity Function and a Late Sharp Cosmic Reionization |
| title_short | Census of Lyα Emission from ∼600 Galaxies at z = 5–14: Evolution of the Lyα Luminosity Function and a Late Sharp Cosmic Reionization |
| title_sort | census of lyα emission from ∼600 galaxies at z 5 14 evolution of the lyα luminosity function and a late sharp cosmic reionization |
| topic | Galaxy evolution High-redshift galaxies Lyα galaxies Reionization |
| url | https://doi.org/10.3847/1538-4365/adc690 |
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