Analysis of Colour-Magnitude Diagrams of Rich LMC Clusters: NGC 1831
Bibliographic record
Abstract
We present a preliminary analysis of a deep colour-magnitude diagram of NGC 1831, a rich cluster in the LMC. The data were obtained with HST/WFPC2 in the F555W and F814W filters, reaching m 555 ⋍ 25 mag. Efficient use of the two-dimensional distribution of data was made by comparing the observed colour-magnitude diagram with model ones. We discuss the process used in accounting for field star contamination and sampling incompleteness in the data. We also describe the algorithm used in building artificial diagrams from model isochrones and the statistical method used in comparing model and data colour-magnitude diagrams. From these comparisons we infer a metallicity Z = 0.008 and a low value, f bin ⋍ 0.25, for the global binary fraction of NGC 1831. We also rule out ages τ ≲ 500 Myr and mass function slope values α ≳ 2.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 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) | 0.002 | 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 teacher head, 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".