The eventful life of a luminous galaxy at <i>z</i> = 14: metal enrichment, feedback, and low gas fraction?
Bibliographic record
Abstract
JADES-GS-z14-0 is the most distant spectroscopically confirmed galaxy yet, 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 Atacama Large Millimeter/submillimeter Array (ALMA) detection of [O III ]88 μm line emission with a significance of 6.67 σ and at a frequency of 223.524 GHz, corresponding to a redshift of 14.1796±0.0007, which is consistent with the candidate C III ] line detected in the NIRSpec spectrum. At this spectroscopic redshift, the Lyman- α break identified with NIRSpec requires a damped Lyman- α absorber with a column density of log( N HI /cm −2 ) = 21.96. The total [O III ]88 μm luminosity (log( L [OIII] /L ⊙ ) = 8.3±0.1) is fully consistent with the local L [OIII] − SFR relation and indicating a gas-phase metallicity >0.1 Z ⊙ . Using prospector spectral energy distribution (SED) modeling and combining the ALMA data with JWST observations, we find Z = 0.17 Z ⊙ and a non-zero escape fraction of ionizing photons (∼11%), which is necessary by the code to reproduce the UV spectrum. We measure an [OIII]5007 Å/[OIII]88 μm line flux ratio between 1 and 20, resulting in an upper limit to the electron density of roughly 700 cm −3 assuming a single-cloud photoionization model. The [O III ]emission line is spectrally resolved, with a FWHM of 102 −22 +29 km s −1 , resulting in a dynamical mass of log(M dyn /M ⊙ ) = 9.0±0.2. When compared to the stellar mass, this value represents a conservative upper limit on the gas mass fraction, which ranges from 50% to 80%, depending on the assumed star formation history. 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.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".