GA-NIFS: witnessing the complex assembly of a star-forming system at <b> <i>z</i> = 5.7</b>
Bibliographic record
Abstract
ABSTRACT We present observations of the $z\sim 5.7$ Lyman-break galaxy HZ10 with the JWST/NIRSpec integral field unit in high and low spectral resolution (G395H, spectral resolving power $R\sim 2700$ and PRISM, $R\sim 100$, respectively), as part of the GA-NIFS programme. By spatially resolving the source (spatial resolution $\sim 0.15{^{\prime \prime }}$ or $\sim 0.9$ kpc), we find three spatially and spectrally distinct regions of line emission along with one region of strong continuum emission, all within a projected distance of $&lt; 10$ kpc. The R2700 data features strong detections in H$\beta$, [O iii] $\lambda \lambda 4959{,}5007$, [N ii] $\lambda \lambda 6548{,}6584$, H$\alpha$, and [S ii] $\lambda \lambda 6716{,}6731$. The R100 data additionally contain a strong detection of the Ly $\alpha$ break, rest-frame UV and optical continuum, and [O ii] $\lambda \lambda 3726{,}3729$. None of the detected lines present strong evidence for active galactic nucleus excitation from line diagnostic diagrams, and no high-ionization lines are detected. Using the detected lines, we constrain the electron density $\left(\rm \log _{10}\left({\it n}_e / cm^{-3}\right)\sim 3\right)$ and metallicity ($\sim 0.5-0.7$ solar) in each component. Spaxel-by-spaxel fits reveal a strong east-west velocity gradient and significant line asymmetries (possibly indicating tidal features or outflows). The western component features a very red UV slope ($\beta _{\rm UV}\sim -0.9$) and significant H $\alpha$ emission, suggesting an evolved population and active star formation. A comparison to high-resolution ($\sim 0.3\,{\rm {arcsec}}$ or $\sim 1.8$ kpc) [${\rm C\, {\small II}}$] $158\, \mu$m imaging obtained with the Atacama Large Millimetre/submillimetre Array (ALMA) reveals areas of dust obscuration. Altogether, these data suggest that HZ10 represents an ongoing merger, with a complex distribution of stars, gas, and dust $&lt; 1$ Gyr after the big bang
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How this classification was reachedexpand
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 | 0.001 | 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 itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, 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".