The ISM Properties and Gas Kinematics of a Redshift 3 Massive Dusty Star-forming Galaxy
Bibliographic record
Abstract
We present CO (J = 1 → 0 3 → 2 5 → 4 10 → 9) and 1.2 kpc resolution [C II] line observations of the dusty star-forming galaxy (SFG) HXMM05—carried out with the Karl G. Jansky Very Large Array, the Combined Array for Research in Millimeter-wave Astronomy, the Plateau de Bure Interferometer, and the Atacama Large Millimeter/submillimeter Array, measuring an unambiguous redshift of z = 2.9850 ± 0.0009. We find that HXMM05 is a hyperluminous infrared galaxy ({L}IR} = (4 ± 1) × 1013 L ⊙) with a total molecular gas mass of (2.1 ± 0.7) × 1011({α }CO}/0.8) M ⊙. The CO (J = 1 → 0) and [C II] emission are extended over ∼9 kpc in diameter, and the CO line FWHM exceeds 1100 km s‑1. The [C II] emission shows a monotonic velocity gradient consistent with a disk, with a maximum rotation velocity of {v}{{c}} = 616 ± 100 km s‑1 and a dynamical mass of (7.7 ± 3.1) × 1011 M ⊙. We find a star formation rate of 2900{}-595+750 M ⊙ yr‑1. HXMM05 is thus among the most intensely SFGs known at high redshift. Photodissociation region modeling suggests physical conditions similar to nearby SFGs, showing extended star formation, which is consistent with our finding that the gas emission and dust emission are cospatial. Its molecular gas excitation resembles the local major merger Arp 220. The broad CO and [C II] lines and a pair of compact dust nuclei suggest the presence of a late-stage major merger at the center of the extended disk, again reminiscent of Arp 220. The observed gas kinematics and conditions, together with the presence of a companion and the pair of nuclei, suggest that HXMM05 is experiencing multiple mergers as a part of the evolution.
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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 | 0.000 |
| 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".