THE INITIAL CONDITIONS OF CLUSTERED STAR FORMATION. II. N<sub>2</sub>H<sup>+</sup>OBSERVATIONS OF THE OPHIUCHUS B CORE
Bibliographic record
Abstract
We present a Nobeyama 45 m Radio Telescope map and Australia Telescope Compact Array pointed observations of N 2 H + 1-0 emission toward the clustered, low-mass star-forming Oph B Core within the Ophiuchus molecular cloud. We compare these data with previously published results of high-resolution NH 3 (1,1) and (2,2) observations in Oph B. We use 3D clumpfind to identify emission features in the single-dish N 2 H + map, and find that the N 2 H + "clumps" match well similar features previously identified in NH 3 (1,1) emission, but are frequently offset to clumps identified at similar resolution in 850 μm continuum emission. Wide line widths in the Oph B2 sub-Core indicate that non-thermal motions dominate the Core kinematics, and remain transonic at densities n ∼ 3 × 10 5 cm −3 with large scatter and no trend with N (H 2 ). In contrast, non-thermal motions in Oph B1 and B3 are subsonic with little variation, but also show no trend with H 2 column density. Over all of Oph B, non-thermal N 2 H + line widths are substantially narrower than those traced by NH 3 , making it unlikely NH 3 and N 2 H + trace the same material, but the v LSR of both species agree well. We find evidence for accretion in Oph B1 from the surrounding ambient gas. The NH 3 /N 2 H + abundance ratio is larger toward starless Oph B1 than toward protostellar Oph B2, similar to recent observational results in other star-forming regions. The interferometer observations reveal small-scale structure in N 2 H + 1-0 emission, which are again offset from continuum emission. No interferometric N 2 H + emission peaks were found to be coincident with continuum clumps. In particular, the ∼1 M ☉ B2-MM8 clump is associated with an N 2 H + emission minimum and surrounded by a broken ring-like N 2 H + emission structure, suggestive of N 2 H + depletion. We find a strong general trend of decreasing N 2 H + abundance with increasing N (H 2 ) in Oph B which matches that found for NH 3 .
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".