The O/H Distribution in NGC 7479: Evidence for a Minor Merger Event
Bibliographic record
Abstract
Results of emission-line spectrophotometry of 68 H II regions in the strongly barred spiral galaxy NGC 7479 obtained with the Multi-Object Spectrograph at the Canada-France-Hawaii Telescope are presented. The average nebular extinction across the galaxy disk is A v ~ 1.1 mag. There is a radial trend (-0.042 ± 0.010 mag kpc -1 ) in the values of reddening suggesting a global difference of about 1.1 mag between the inner and outer parts of the galaxy. All the H II regions fall within the well-defined sequences of normal H II regions in the standard diagnostic diagrams [O III]/Hβ versus [N II]/Hα, and [O III]/Hβ versus [O I]/Hα. The values of excitation ([O III]/Hβ) of the regions located in the western arm are higher by about 0.4 dex compared to those of the eastern arm and central regions. There is evidence that the ionization parameter is higher and the electronic density lower in these regions. The global O/H abundance gradient is shallow (~-0.025 ± 0.005 dex kpc -1 ), in agreement with what is found for galaxies with a strong bar. No break is seen in the O/H radial gradient. The azimuthal O/H variations in the disk are small at less than 0.3 dex. These results are discussed in the framework of a merger in which NGC 7479 captured a small galaxy about 3 × 10 8 yr ago.
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| 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".