On the Relevance of the Tremaine‐Weinberg Method Applied to an Hα Velocity Field: Pattern Speed Determination in M100 (NGC 4321)
Bibliographic record
Abstract
The relevance of the Tremaine-Weinberg (TW) method is tested for measuring bar, spiral, and inner structure pattern speeds using a gaseous velocity field. The TW method is applied to various simulated barred galaxies in order to demonstrate its validity in seven different configurations, including star formation and/or dark matter halo. The reliability of the different physical processes involved and of the various observational parameters is also tested. The simulations show that the TW method could be applied to gaseous velocity fields to get a good estimate of the bar pattern speed, under the condition that regions of shocks are avoided and measurements are confined to regions where the gaseous bar is well formed. We successfully apply the TW method to the Hα velocity field of the Virgo Cluster galaxy M100 (NGC 4321) and derive pattern speeds of 55 ± 5 km s -1 kpc -1 for the nuclear structure, 30 ± 2 km s -1 kpc -1 for the bar, and 20 ± 1 km s -1 kpc -1 for the spiral pattern, in full agreement with published determinations using the same method or alternative ones.
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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 | 0.003 | 0.016 |
| 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 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 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".