ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): Density Structure of Centrally Concentrated Prestellar Cores from Multiscale Observations
Bibliographic record
Abstract
Abstract Starless cores represent the initial stage of evolution toward (proto)star formation, and a subset of them, known as prestellar cores, with high density (∼ 106 cm−3 or higher) and being centrally concentrated are expected to be embryos of (proto)stars. Determining the density profile of prestellar cores therefore provides an important opportunity to gauge the initial conditions of star formation. In this work, we perform rigorous modeling to estimate the density profiles of three nearly spherical prestellar cores among a sample of five highly dense cores detected by our recent observations. We employed multiscale observational data of the (sub)millimeter dust continuum emission, including those obtained by SCUBA-2 on the James Clerk Maxwell Telescope with a resolution of ∼ 5600 au and by multiple Atacama Large Millimeter/submillimeter Array observations with a resolution as high as ∼ 480 au. We are able to consistently reproduce the observed multiscale dust continuum images of the cores with a simple prescribed density profile, which bears an inner region of flat density and an r −2 profile toward the outer region. By utilizing the peak density and the size of the inner flat region as a proxy for the dynamical stage of the cores, we find that the three modeled cores are most likely unstable and prone to collapse. The sizes of the inner flat regions, as compact as ∼ 500 au, signify them as being the highly evolved prestellar cores rarely found to date.
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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) | 0.000 | 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".