JADES and SAPPHIRES: galaxy metamorphosis amidst a huge, luminous emission-line region
Bibliographic record
Abstract
ABSTRACT We report the discovery of a remarkably large and luminous line-emitting nebula extending on either side of the Balmer-break galaxy JADES-GS-518794 at $z=5.89$, detected with James Webb Space Telescope (JWST)/NIRCam imaging in [O iii]$\lambda \lambda$4959, 5007 and H α and spectroscopically confirmed with NIRCam/wide-field slitless spectroscopy, thanks to the pure-parallel programme Slitless Areal Pure Parallel HIgh-Redshift Emission Survey. The end-to-end velocity offset is $\Delta v=830\pm 130~\mathrm{km\, s^{-1}}$. Nebulae with such large sizes and high luminosities (25 pkpc diameter, $L_{\mathrm{ [\text{O} \,{{\small III}}]}}=1.2\times 10^{10}~\mathrm{L_\odot }$) are routinely observed around bright quasars, unlike JADES-GS-518794. With a stellar mass of $10^{10.1}~{\rm M}_\odot $, this galaxy is at the knee of the mass function at $z=6$. Its star formation rate declined for some time (10–100 Myr prior to observation), followed by a recent (10 Myr) upturn. This system is part of a candidate large-scale galaxy overdensity, with an excess of Balmer-break galaxies compared to the field (3σ). We discuss the possible origin of this nebula as material from a merger or gas expelled by an active galactic nucleus (AGN). The symmetry of the nebula, its bubble-like morphology, kinematics, high luminosity, and the extremely high equivalent width of [O iii] together favour the AGN interpretation. Intriguingly, there may be a physical connection between the presence of such a large, luminous nebula and the possible metamorphosis of the central galaxy towards quenching.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".