AstroSat/UVIT Cluster Photometry in the Northern Disk of M31
Bibliographic record
Abstract
Abstract The Andromeda galaxy (M31) is an object of ongoing study with the Ultraviolet Imaging Telescope (UVIT) on AstroSat. UVIT far-UV (FUV) and near-UV (NUV) photometry is carried out here for a set of 239 clusters in the NE disk and bulge of M31 that overlap with the HST/PHAT survey. Padova stellar models were applied to derive ages, masses, metallicities, and extinctions for 170 clusters. The ages show a narrow peak at ∼4 Myr and a broad peak around 100 Myr. log( Z / Z ⊙ ) values are mostly between −0.3 and +0.3. The 7 clusters in the bulge have a low metallicity and high mass. Most clusters are in the spiral arms and have metallicities in the range noted above. The youngest clusters mostly have high metallicity and are concentrated along the brightest parts of the spiral arms. The UVIT FUV and NUV data are sensitive to young stars and detect a new metal-rich peak in star formation in the disk at age ∼4 Myr.
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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 | 0.001 |
| 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 | 0.001 |
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".