TY - JOUR
T1 - Ionizing Photon Production Efficiencies and Chemical Abundances at Cosmic Dawn Revealed by Ultradeep Rest-frame Optical Spectroscopy of JADES-GS-z14-0
AU - Helton, Jakob M.
AU - Morrison, Jane E.
AU - Hainline, Kevin N.
AU - D’Eugenio, Francesco
AU - Rieke, George H.
AU - Alberts, Stacey
AU - Carniani, Stefano
AU - Leja, Joel
AU - Li, Yijia
AU - Rinaldi, Pierluigi
AU - Scholtz, Jan
AU - Stone, Meredith
AU - Willmer, Christopher N. A.
AU - Wu, Zihao
AU - Baker, William M.
AU - Bunker, Andrew J.
AU - Charlot, Stephane
AU - Chevallard, Jacopo
AU - Cleri, Nikko J.
AU - Curti, Mirko
AU - Curtis-Lake, Emma
AU - Egami, Eiichi
AU - Eisenstein, Daniel J.
AU - Jakobsen, Peter
AU - Ji, Zhiyuan
AU - Johnson, Benjamin D.
AU - Kumari, Nimisha
AU - Lin, Xiaojing
AU - Lyu, Jianwei
AU - Maiolino, Roberto
AU - Maseda, Michael
AU - Pérez-González, Pablo G.
AU - Rieke, Marcia J.
AU - Robertson, Brant
AU - Saxena, Aayush
AU - Sun, Fengwu
AU - Tacchella, Sandro
AU - Übler, Hannah
AU - Venturi, Giacomo
AU - Williams, Christina C.
AU - Willott, Chris
AU - Witstok, Joris
AU - Zhu, Yongda
N1 - © 2026. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. https://creativecommons.org/licenses/by/4.0/
PY - 2026/6/20
Y1 - 2026/6/20
N2 - JWST has discovered an early period of galaxy formation that was more vigorous than expected, which has challenged our understanding of the early Universe. In this work, we present the longest spectroscopic integration ever acquired by JWST/MIRI (tobs ≈ 51 hr). This spectrum covers the brightest rest-frame optical nebular emission lines for the luminous galaxy JADES-GS-z14-0 at z = 14.18. Most notably, we detect [O III]λλ4959, 5007 at ≈14σ and Hα at ≈4σ with these ultradeep observations. These lines reveal that JADES-GS-z14-0 has low dust attenuation with a recent star formation rate of SFR ≈ 8 ± 2M⊙ yr−1, star formation rate surface density of ΣSFR ≈ 20 ± 5M⊙ yr−1 kpc−2, and ionizing photon production efficiency of ξion ≈ 1025.3±0.1 Hz erg−1. Using standard strong-line diagnostics, we infer a gas-phase oxygen abundance of log10(O/H)+12≈7.5±0.2 (≈6%Z⊙), carbon-to-oxygen ratio of [C/O] ≈ −0.4 ± 0.2, ionization parameter of log10(U)≳−2.4 , and density of nH ≈ 690 ± 200 cm−3. Using detailed photoionization modeling, we instead derive log10(O/H)+12≈8.5−0.4+0.4 (≈60%Z⊙), log10(U)≈−1.4−0.4+0.3 , and nH≈540−320+520cm−3 . The inferred properties of JADES-GS-z14-0 are similar to those measured for similarly luminous galaxies at z > 10 with previous MIRI/Spectroscopy, such as GHZ2/GLASSz12, GN-z11, and MACS0647-JD1. These results suggest extreme ionization conditions and rapid metal enrichment less than 300 Myr after the Big Bang. Existing simulations are unable to reproduce the empirical and inferred properties of JADES-GS-z14-0. This work demonstrates an important step toward understanding the formation of the first stars and heavy elements in the Universe. Future work will focus on the detection of the rest-frame optical continuum and its interpretation for the stellar population properties of JADES-GS-z14-0.
AB - JWST has discovered an early period of galaxy formation that was more vigorous than expected, which has challenged our understanding of the early Universe. In this work, we present the longest spectroscopic integration ever acquired by JWST/MIRI (tobs ≈ 51 hr). This spectrum covers the brightest rest-frame optical nebular emission lines for the luminous galaxy JADES-GS-z14-0 at z = 14.18. Most notably, we detect [O III]λλ4959, 5007 at ≈14σ and Hα at ≈4σ with these ultradeep observations. These lines reveal that JADES-GS-z14-0 has low dust attenuation with a recent star formation rate of SFR ≈ 8 ± 2M⊙ yr−1, star formation rate surface density of ΣSFR ≈ 20 ± 5M⊙ yr−1 kpc−2, and ionizing photon production efficiency of ξion ≈ 1025.3±0.1 Hz erg−1. Using standard strong-line diagnostics, we infer a gas-phase oxygen abundance of log10(O/H)+12≈7.5±0.2 (≈6%Z⊙), carbon-to-oxygen ratio of [C/O] ≈ −0.4 ± 0.2, ionization parameter of log10(U)≳−2.4 , and density of nH ≈ 690 ± 200 cm−3. Using detailed photoionization modeling, we instead derive log10(O/H)+12≈8.5−0.4+0.4 (≈60%Z⊙), log10(U)≈−1.4−0.4+0.3 , and nH≈540−320+520cm−3 . The inferred properties of JADES-GS-z14-0 are similar to those measured for similarly luminous galaxies at z > 10 with previous MIRI/Spectroscopy, such as GHZ2/GLASSz12, GN-z11, and MACS0647-JD1. These results suggest extreme ionization conditions and rapid metal enrichment less than 300 Myr after the Big Bang. Existing simulations are unable to reproduce the empirical and inferred properties of JADES-GS-z14-0. This work demonstrates an important step toward understanding the formation of the first stars and heavy elements in the Universe. Future work will focus on the detection of the rest-frame optical continuum and its interpretation for the stellar population properties of JADES-GS-z14-0.
KW - Chemical abundances
KW - Emission line galaxies
KW - Galaxy formation
KW - Galaxy evolution
KW - High-redshift galaxies
KW - Infrared spectroscopy
U2 - 10.3847/2041-8213/ae7446
DO - 10.3847/2041-8213/ae7446
M3 - Article
SN - 2041-8205
VL - 1004
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 2
ER -