Probing fragmentation with ALMA continuum and spectral line observations of the dense clumps in the ℓ = 224° region
Bibliographic record
Abstract
ABSTRACT We report observations, performed with the Atacama Large Millimeter/submillimeter Array (ALMA), of 1 mm dust continuum emission and molecular line emission in 13CO(2–1) and C18O(2–1), towards a sample of starless and protostellar clumps selected from a region, towards the ℓ = 224° field, of the Herschel Infrared GALactic Plane Survey (Hi-GAL). Using the ALMA images and a source extraction algorithm we have analysed the small-scale (∼1000 AU) structure of the clumps and their population of cores (or fragments). We find in general multiple cores in each Hi-GAL clump, both in the continuum and spectral lines, but we do not find a dominant fragmentation mode and the morphologies are very different among the various sources. Our results suggest that during the transition phase from clump to core, those sources with a higher core formation efficiency are also associated with parent clumps that are more likely to convert a higher fraction of their initial mass into a single or a few cores. We were able to obtain a core mass function, or CoMF, covering masses in the range ∼2 × 10−3 to ∼1 M⊙ for the C18O cores, and ∼4 × 10−2 to ∼10 M⊙ for the continuum cores. We find that the CoMF in our sample is much shallower than the higher mass ($\gtrsim 1$ M⊙) IMF, thus indicating that while approaching the final phase of fragmentation the mass function does not resemble the IMF more closely.
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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 | 0.000 |
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".