Residuals of an equilibrium model for the galaxy reveal a state of disequilibrium in the Solar Neighbourhood
Bibliographic record
Abstract
ABSTRACT We simultaneously model the gravitational potential and phase space distribution function (DF) of giant stars near the Sun using the Gaia DR2 radial velocity catalogue. We assume that the Galaxy is in equilibrium and is symmetric about both the spin axis of the disc and the Galactic mid-plane. The potential is taken as a sum of terms that nominally represent contributions from the gas and stellar discs, the bulge, and the dark matter halo. Our model for the DF comprises two components to account for a mix of thin and thick disc stars. Each component is described by an analytic function of the energy, the spin angular momentum, and the vertical energy, in accord with Jeans theorem. We present model predictions for the radial and vertical forces within $\sim 2\, {\rm kpc}$ of the Sun, highlighting the rotation curve, the asymmetric drift curve, and the vertical force profile. We then show residuals for star counts in the R–z and z–vz planes as well as maps of the mean radial and azimuthal velocities in the z–vz plane. Using our model for the potential, we map the star count residuals in action-frequency-angle coordinates. The Gaia phase spiral, velocity arches, bending waves, and some of the known moving groups appear as well-defined features in these maps.
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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 | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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) | 0.003 | 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".