Dynamics of Dense Cores in the Perseus Molecular Cloud
Bibliographic record
Abstract
We survey the kinematics of over 150 candidate (and potentially star-forming) dense cores in the Perseus molecular cloud with pointed N 2 H + (1-0) and simultaneous C 18 O(2-1) observations. Our detection rate of N 2 H + is 62%, rising to 84% for SCUBA-selected targets. In agreement with previous observations, we find that the dense N 2 H + targets tend to display nearly thermal line widths, particularly those that appear to be starless (using Spitzer data), indicating that turbulent support on the small scales of molecular clouds is minimal. For those N 2 H + targets that have an associated SCUBA dense core, we find that their internal motions are more than sufficient to provide support against the gravitational force on the cores. Comparison of the N 2 H + integrated intensity and SCUBA flux reveals fractional N 2 H + abundances between 10 -10 and 10 -9 . We demonstrate that the relative motion of the dense N 2 H + gas and the surrounding C 18 O gas is less than the sound speed in the vast majority of cases (~90%). The point-to-point motions we observe within larger extinction regions appear to be insufficient to provide support against gravity, although we sparsely sample these regions.
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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 | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.005 | 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".