Jakob M. Helton, Jane Morrison, Kevin Hainline, Francesco D’Eugenio, G. H. Rieke, Stacey Alberts, Stefano Carniani, Joel Leja, Yijia Li, Pierluigi Rinaldi, Jan Scholtz, Meredith A. Stone, Christopher N. A. Willmer, Zihao Wu, William Baker, Andrew J. Bunker, S. Charlot, Jacopo Chevallard, Nikko J. Cleri, Mirko Curti, Emma Curtis-Lake, Eiichi Egami, Daniel J. Eisenstein, P. Jakobsen, Zhiyuan Ji, Benjamin D. Johnson, Nimisha Kumari, Xiaojing Lin, Jianwei Lyu, R. Maiolino, Michael V. Maseda, Pablo G. Pérez‐González, Marcia Rieke, Brant Robertson, Aayush Saxena, Fengwu Sun, Sandro Tacchella, Hannah Übler, Giacomo Venturi, Christina C. Williams, Chris J. Willott, Joris Witstok, Yongda Zhu
Abstract 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 ( t obs ≈ 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 ] λλ 4959, 5007 at ≈14 σ and H α at ≈4 σ 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 ± 2 M ⊙ yr −1 , star formation rate surface density of Σ SFR ≈ 20 ± 5 M ⊙ yr −1 kpc −2 , and ionizing photon production efficiency of ξ ion ≈ 10 25.3±0.1 Hz erg −1 . Using standard strong-line diagnostics, we infer a gas-phase oxygen abundance of log 10 ( O / H ) + 12 ≈ 7.5 ± 0.2 (≈6% Z ⊙ ), carbon-to-oxygen ratio of [C/O] ≈ −0.4 ± 0.2, ionization parameter of log 10 ( U ) ≳ − 2.4 , and density of n H ≈ 690 ± 200 cm −3 . Using detailed photoionization modeling, we instead derive log 10 ( O / H ) + 12 ≈ 8 . 5 − 0.4 + 0.4 (≈60% Z ⊙ ), log 10 ( U ) ≈ − 1 . 4 − 0.4 + 0.3 , and n H ≈ 54 0 − 320 + 520 cm − 3 . The inferred properties of JADES-GS-z14-0 are similar