Bibliographic record
Abstract
Wide-field images obtained with the 3.6 meter Canada-France-Hawaii Telescope are used to investigate the spatial distribution and photometric properties of the brightest stars in the disk of M81 (NGC 3031). With the exception of the central ∼ 2 kpc of the galaxy and gaps between CCDs, the survey is spatially complete for stars with i ′ < 24 and major axis distances of 18 kpc. A more modest near-infrared survey detects stars with K < 20 over roughly one third of the disk. Bright main sequence (MS) stars and RSGs are traced out to galactocentric distances of at least 18 kpc. The color of the red supergiant (RSG) locus suggests that Z = 0.008 when RGC> 6 kpc, and such a radially uniform RSG metallicity is consistent with [O/H] measurements from HII regions. The density of bright MS stars and RSGs drops when RGC < 4 kpc, suggesting that star formation in the inner disk was curtailed within the past ∼ 100 Myr. The spatial distribution of bright MS stars tracks emission at far-ultraviolet, mid- and far-infrared wavelengths, although tidal features contain bright MS stars but have little or no infrared flux. The specific frequency of bright MS stars and RSGs, normalized to K−band integrated brightness, increases with radius, indicating that during the past ∼ 30 Myr the specific star formation rate (SSFR) has increased with increasing radius. Still, the SSFR of the M81 disk at intermediate radii is consistent with that expected for an isolated galaxy as massive as M81, indicating that the star formation rate in the disk of M81 has not been markedly elevated during the past few tens of millions of years. The stellar content of the M81 disk undergoes a distinct change near RGC ∼ 14 kpc; the K−band light profile,
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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 | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 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) | 0.004 | 0.003 |
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".