JWST imaging of omega Centauri
Bibliographic record
Abstract
We present a detailed analysis of the white dwarf (WD) cooling sequence (CS) in omega Centauri based on combined Hubble Space Telescope (HST) and JWST observations. Our analysis confirms the previously reported split –based on HST observations in ultraviolet filters – in the upper part of the WD CS, which is consistent with the presence of two distinct WD populations. We extend its study to a significantly fainter and cooler limit (down to ∼8000 K), which corresponds to cooling ages of about 1 Gyr. We used artificial star tests and cooling models to confirm that the split is evidence of two WD populations with different masses and progenitors: one sequence of ‘canonical’ WDs produced by the He-normal progenitors and one sequence of low-mass WDs that originated from the cluster He-rich component. We show that the fraction of WDs from the He-rich component in the outer regions is smaller than that found in the innermost regions. We also studied the kinematics of WDs and show that in the outer regions, the velocity distribution of WDs from He-rich progenitors is slightly radially anisotropic, while that of canonical WDs is slightly tangentially anisotropic. Both the radial variation in the fraction of WDs from the He-rich population and the difference between their velocity distribution and that of canonical WDs are consistent with spatial and kinematic differences previously found for He-rich and He-normal main-sequence stars and are in general agreement with models that predict that He-rich stars form more centrally concentrated than He-normal 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 | 0.003 | 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) | 0.002 | 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".