Bibliographic record
Abstract
Aims. We report on an estimate of the bar pattern speed for the low surface brightness spiral galaxy UGC 628.Methods. We applied the Tremaine-Weinberg method to high resolution Hα velocity and integrated emission maps of this dark matter dominated galaxy. Observations were made at the CFHT using the optical Fabry-Perot interferometer, FaNTOmM.Results. The Tremaine-Weinberg method estimates a bar pattern speed of (11.3 ± 2.0) km s-1 kpc-1 for UGC 628, which is among the lowest values found for a spiral galaxy. The corotation radius Rc of the bar and the gaseous disc is kpc, implying a ratio of , where aB is the bar radius. The ratio is well beyond the usual range of values, 1.0 ≤ ≤ 1.4, found for fast bars of high surface brightness barred galaxies. This implies that the bar in UGC 628 is slow.Conclusions. As shown through the use of numerical simulations, fast bars survive when the inner mass distribution of galaxies is dominated by the baryons over the dark matter. Our result suggests that the presence of slow bars in galaxies is likely related to the dominance of dark matter over the mass distribution.
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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 | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 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".