Current Star Formation in the Perseus Molecular Cloud: Constraints from Unbiased Submillimeter and Mid‐Infrared Surveys
Bibliographic record
Abstract
We present a census of the population of deeply embedded young stellar objects (YSOs) in the Perseus molecular cloud complex based on a combination of Spitzer Space Telescope mid-infrared data from the Cores to Disks (c2d) legacy team and JCMT SCUBA submillimeter maps from the COMPLETE team. The mid-infrared sources detected at 24 μm and having [3.6] - [4.5] > 1 are located close to the center of the SCUBA cores, typically within 15'' of their peaks. The narrowness of the spatial distribution of mid-infrared sources around the peaks of the SCUBA cores suggests that no significant dispersal of the newly formed YSOs has occurred. This argues against the suggestion that motions of protostars regulate the timescales over which significant (Bondi-Hoyle) accretion can occur. The YSOs are found to have red [3.6] - [4.5] and [8.0] - [24] colors, but not comparable red [5.8] - [8.0] colors. The most deeply embedded YSOs are found in regions with high extinction, A V ≥ 5, similar to the extinction threshold observed for the SCUBA cores. All the SCUBA cores with high concentrations have embedded YSOs, but not all cores with low concentrations are starless. From the above considerations, a relatively unbiased sample of 49 deeply embedded YSOs is constructed. Embedded YSOs are found in 40 of the 72 SCUBA cores, with only three cores harboring multiple embedded YSOs within 15''. The equal number of SCUBA cores with and without embedded YSOs suggests that the timescale for the evolution through the dense prestellar stages, where the cores are recognized in the submillimeter maps and have central densities of 5 × 10 4 -1 × 10 5 cm -3 , is similar to the timescale for the embedded protostellar stages. The current star formation efficiency of cores is estimated to be approximately 10%-15%. In contrast, the star formation efficiency averaged over the cloud lifetime and compared to the total cloud mass is only a few percent, reflecting also the efficiency in assembling cloud material into the dense cores actually forming stars.
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".