Panchromatic properties of the extreme Fe ii emitter PHL 1092
Bibliographic record
Abstract
ABSTRACT We present near-infrared spectroscopy of the NLS1 galaxy PHL 1092 (z = 0.394), the strongest Fe ii emitter ever reported, combined with optical and UV data. We modelled the continuum and the broad emission lines using a power-law plus a blackbody function and Lorentzian functions, respectively. The strength of the Fe ii emission was estimated using the latest Fe ii templates in the literature. We re-estimate the ratio between the Fe ii complex centred at 4570 Å and the broad component of H β, R4570, obtaining a value of 2.58, nearly half of that previously reported (R4570 = 6.2), but still placing PHL 1092 among extreme Fe ii emitters. The full width at half-maximum (FWHM) values found for low-ionization lines are very similar (FWHM ∼ 1200 km s−1), but significantly narrower than those of the hydrogen lines (FWHMH β ∼ 1900 km s−1). Our results suggest that the Fe ii emission in PHL 1092 follows the same trend as in normal Fe ii emitters, with Fe ii being formed in the outer portion of the BLR and co-spatial with Ca ii, and O i, while H β is formed closer to the central source. The flux ratio between the UV lines suggests high densities, log(nH) ∼ 13.0 cm−3, and a low ionization parameter, log(U) ∼ −3.5. The flux excess found in the Fe ii bump at 9200 Å after the subtraction of the NIR Fe ii template and its comparison with optical Fe ii emission suggests that the above physical conditions optimize the efficiency of the Ly α-fluorescence process, which was found to be the main excitation mechanism in the Fe ii production. We discuss the role of PHL 1092 in the eigenvector 1 context.
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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 | 0.000 | 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) | 0.001 | 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".