GA-NIFS: ISM properties and metal enrichment in a merger-driven starburst during the epoch of reionization probed with <i>JWST</i> and ALMA
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
ABSTRACT We present deep JWST/NIRSpec integral-field spectroscopy (IFS) and ALMA [C ii]$\lambda $158$\mu$m observations of COS-3018, a star-forming galaxy at z $\sim$ 6.85, as part of the GA-NIFS programme. Both G395H (R $\sim$ 2700) and PRISM (R $\sim$ 100) NIRSpec observations revealed that COS-3018 is comprised of three separate components detected in [O iii]$\lambda $5007, which we dub as Main, North, and East, with stellar masses of 10$^{9.4 \pm 0.1}$, 10$^{9.2 \pm 0.07}$, 10$^{7.7 \pm 0.15}$ $\mathrm{M}_\odot$. We detect [O iii]$\lambda $$\lambda $5007,4959, [O ii]$\lambda $$\lambda $3727,3729, and multiple Balmer lines in all three components together with [O iii]$\lambda $4363 in the Main and North components. This allows us to measure an interstellar medium temperature of $T_\text{e}$ = 1.27$\pm 0.07\times 10^4$ and $T_\text{e}$ = 1.6$\pm 0.14\times 10^4$ K with densities of $n_{e}$ = 1250$\pm$250 and $n_{e}$ = 700$\pm$200 cm$^{-3}$, respectively. These deep observations allow us to measure an average metallicity of 12 + log(O/H) = 7.9–8.2 for the three components with the T$_{e}$-method. We do not find any significant evidence of metallicity gradients between the components. Furthermore, we also detect [N ii]$\lambda $6585, one of the highest redshift detections of this emission line. We find that in a small, metal-poor clump 0.2 arcsec west of the North component, N/O is elevated compared to other regions, indicating that nitrogen enrichment originates from smaller substructures, possibly proto-globular clusters. [O iii]$\lambda $5007 kinematics show that this system is merging, which is probably driving the ongoing, luminous starburst.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 it