An integral field spectroscopic study of stellar and ionized gas properties around edge-on disc galaxies in the stellar mass range 9 &lt; log <i>M</i>* &lt; 11
Bibliographic record
Abstract
ABSTRACT We analyse the stellar light, 4000 Å break and emission line profiles of 82 edge-on disc galaxies from the Mapping Nearby Galaxies at APO (MaNGA) survey. We characterize the stellar light profiles perpendicular to the disc plane using two parameters: (a) the power-law slope of the thick disc component and (b) the transition radius where the profile flattens. The 4000 Å break profiles perpendicular to the plane are characterized by the number of significant changes in slope (breaks) and by the change in D$_n$(4000) from inner to outer disc. The slope correlates tightly with the stellar mass of the galaxy over the stellar mass range $10^9< \log M_* < 10^{10} \,\mathrm{ M}_{\odot }$. More massive galaxies have more extended thick discs. The slope and transition radius exhibit large scatter for galaxies more massive than $10^{10} \,\mathrm{ M}_{\odot }$. Half the sample have older stellar populations in their thick discs, a third have flat D$_n$(4000) profiles and 15 per cent have younger thick discs. The D$_n$(4000) profiles exhibit as many as four separate breaks. There are more breaks in massive galaxies with bulges and more extended thick discs. This may indicate that the breaks are produced by more frequent accretion events in such systems. The extraplanar H$\alpha$ equivalent width (EQW) correlates most strongly with the specific star formation rate (SFR) of the galaxy, and the [O ii]/H$\alpha$ ratio increases with distance from the disc plane. This increase is most apparent for massive galaxies with extended thick disc components and low SFR/$M_*$. These findings support the hypothesis that the larger [O ii]/H$\alpha$ ratios may be caused by ionization from evolved stars.
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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 | 0.000 | 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) | 0.001 | 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".