Testing four formation hypotheses -- supernova shell compression, thermal instability, turbulent fragmentation, and Galactic spiral arm interaction -- using Bayesian model comparison against observed LRCC properties.
| Model | Log-Likelihood | Posterior | Vel. Disp. (km/s) | SF Ratio | Verdict |
|---|---|---|---|---|---|
| Spiral Arm | -4.25 | 0.898 | 1.10 | 2.93 | Best Model |
| Thermal Instability | -6.42 | 0.102 | 0.33 | 0.25 | Viable |
| Turbulent Frag. | -5,879 | ~0 | 1.33 | 4.48 | Rejected |
| Supernova Shell | -63,374 | ~0 | 5.52 | 64.7 | Rejected |
| Combined Model | Posterior | Description |
|---|---|---|
| Spiral Arm (alone) | 0.895 | Best overall model |
| Arm + TI | 0.002 | Spiral arm compression triggers TI |
| SN + TI | ~0 | SN compression triggers TI |