Radial migration in disc galaxies - I. Transient spiral structure and dynamics
Bibliographic record
Abstract
We seek to understand the origin of radial migration in spiral galaxies by analysing in detail the structure and evolution of an idealized, isolated galactic disc. To understand the redistribution of stars, we characterize the time evolution of properties of spirals that spontaneously form in the disc. Our models unambiguously show that in such discs, single spirals are unlikely, but that a number of transient patterns may coexist in the disc. However, we also show that while spirals are transient in amplitude, at any given time the disc favours patterns of certain pattern speeds. Using several runs with different numerical parameters we show that the properties of spirals that occur spontaneously in the disc do not sensitively depend on resolution. The existence of multiple transient patterns has large implications for the orbits of stars in the disc, and we therefore examine the resonant scattering mechanisms that profoundly alter angular momenta of individual stars. We confirm that the corotation scattering mechanism described by Sellwood & Binney is responsible for the largest angular momentum changes in our simulations.
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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 | 0.002 |
| 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 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 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".