The Bulge-Halo Connection in Galaxies: A Physical Interpretation of the <i>V</i> <sub> <i>c</i> </sub> -σ <sub>0</sub> Relation
Bibliographic record
Abstract
We explore the dependence of the ratio of a galaxy's maximum circular velocity, V c , to its central velocity dispersion, σ 0 , on morphology or, equivalently, total light concentration. Such a dependence is expected if light traces the mass. Over the full range of galaxy types, masses, and brightnesses, and assuming that the gas velocity traces the circular velocity, we find that galaxies obey the relation log( V c /σ 0 ) = 0.63 - 0.11 C 28 , where C 28 = 5 log( r 80 / r 20 ) and the radii are measured at 80% and 20% of the total light. Massive galaxies scatter about the V c = σ 0 line for isothermal stellar systems. For pure disks, C 28 ~ 2.8 and V c ≃ 2σ 0 . Self-consistent equilibrium galaxy models from Widrow & Dubinski constrained to match the size-luminosity and velocity-luminosity relations of disk galaxies fail to match the observed V c /σ 0 distribution. Furthermore, the matching of dynamical models for V c ( r )/σ( r ) with observations of dwarf and elliptical galaxies suffers from limited radial coverage and relatively large error bars; for dwarf systems, however, kinematical measurements at the galaxy center and optical edge suggest V c ( R max ) ≳ 2σ 0 [in contrast with past assumptions that V c ( R max ) = σ 0 for dwarfs]. The V c -σ 0 - C 28 relation has direct implications for galaxy formation and dynamical models, galaxy scaling relations, the mass function of galaxies, and the links between the formation and evolution processes of a galaxy's central massive object, bulge, and dark matter halo.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 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) | 0.002 | 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".