Ages and Metallicities of Globular Clusters in NGC 4472
Bibliographic record
Abstract
We have derived ages and metallicities from co-added spectra of 131 globular clusters (GCs) associated with the giant Virgo elliptical NGC 4472. ¿From their metal-line indices, we find that our sample of GCs span a metallicity range of approximately −1.6 ≤ [Fe/H] ≤ 0 dex. The SSP models of Worthey (1994; W94) predict that the metal-poor population of GCs has an age of 14.5 ± 4 Gyr and that the metal-rich population is 13.8 ± 6 Gyr old, whilst the models of Kurth, Fritze-v. Alvensleben & Fricke (1999; KFF99) predict ages of 6.0 ± 2 and 8.0 ± 5 respectively. We conclude that, within the uncertainties, the GCs are old and coeval, and that the bimodality seen in the broadband colours primarily reflects metallicity and not age differences.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 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".