The Eventful Life of a Luminous Galaxy at Z = 14: Metal Enrichment, Feedback, and Low Gas Fraction?

JADES-GS-z14-0 is the most distant spectroscopically confirmed galaxy so far, at z>14. With a UV magnitude of -20.81, it is one of the most luminous galaxies at cosmic dawn and its half-light radius of 260 pc means that stars dominate the observed UV emission. We report the ALMA detection of [OIII]88μm line emission with a significance of 6.67σ and at a frequency of 223.524 GHz, corresponding to a redshift of 14.1796±0.0007, which is consistent with the candidate CIII] line detected in the NIRSpec spectrum. At this spectroscopic redshift, the Lyman break identified with NIRSpec requires a damped Lyman-α absorber with a column density of log(N_ HI/cm^-2)=22.23. The total [OIII]88μm luminosity (log((L_ [OIII]/L_⊙) = 8.3±0.1) is fully consistent with the local L_ [OIII]-SFR relation. Based on the L_ [OIII]/SFR, we infer a gas-phase metallicity >0.1 Z_⊙, which is somewhat unexpected given the weakness of the UV emission lines. Using prospector SED modeling and combining the ALMA data with JWST observations, we find Z=0.17 Z_⊙ and an escape fraction of ionizing photons of 20 to explain the UV spectrum. We measure an [O III]5007Å/[O III]88μm line flux ratio between 1 and 10, resulting in an upper limit to the electron density of roughly 300 cm^-3, which is lower than those measured in other high-z luminous galaxies. The [OIII]88μm emission line is spectrally resolved, with a FWHM of 100 km/s, resulting in a dynamical mass of log(M_ dyn/M_⊙) = 9.0±0.2. This value is comparable to the stellar mass derived from the SED fitting, which implies a very low gas fraction. Past radiation-driven outflows may have cleared the galaxy from the gas, reducing the gas fraction and thus increasing the escape fraction of ionizing photons.