GA-NIFS: Black hole and host galaxy properties of two<i>z</i>≃ 6.8 quasars from the NIRSpec IFU
Bibliographic record
Abstract
Aims.Integral field spectroscopy (IFS) with JWST NIRSpec will significantly improve our understanding of the first quasars, by providing spatially resolved, infrared spectroscopic capabilities that cover key rest-frame optical emission lines that have been previously unobservable. Methods.Here we present our results from the first twoz > 6 quasars observed as a part of the Galaxy Assembly with NIRSpec IFS (GA-NIFS) GTO programme, with DELS J0411–0907 atz = 6.82 and VDES J0020–3653 atz = 6.86. Results.By observing the Hβ, [O III]λλ4959, 5007, and Hαemission lines in these high-zquasars for the first time, we measured accurate black hole masses,MBH = 1.85−0.8+2 × 109 M⊙and 2.9−1.3+3.5 × 109M⊙, corresponding to Eddington ratios ofλEdd = 0.8−0.4+0.7and 0.4−0.2+0.3for DELS J0411–0907 and VDES J0020–3653, respectively. These provide a key comparison for existing estimates from the more uncertain Mg IIline. We performed quasar–host decomposition using models of the quasars’ broad lines to measure the underlying host galaxies. We also discovered multiple emission line regions surrounding each of the host galaxies, which are likely companion galaxies undergoing mergers with these hosts. We measured the star formation rates, excitation mechanisms, and dynamical masses of the hosts and companions, measuring theMBH/Mdynratios at highzusing these estimators for the first time. DELS J0411–0907 and VDES J0020–3653 both lie above the local black hole–host mass relation, and are consistent with the existing observations ofz ≳ 6 quasar host galaxies with ALMA. We detected ionised outflows in [O III]λλ4959, 5007 and Hβfrom both quasars, with mass outflow rates of 58−37+44and 525−92+75 M⊙yr−1for DELS J0411–0907 and VDES J0020–3653, much larger than their host star formation rates of < 33 and < 54 M⊙yr−1, respectively. Conclusions.This work highlights the exceptional capabilities of the JWST NIRSpec IFU for observing quasars in the early Universe.
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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 | 0.001 | 0.001 |
| 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 | 0.001 |
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".