Disk Component
Bulge Component
Dark Matter Halo (NFW)
Display Options
Statistics at 8 kpc (Solar Circle)
Dark Matter Evidence
Rotation curves measure the circular velocity v(r) of stars and gas orbiting a galaxy at different radii.
Key Physics:
- v² = GM(<r)/r (circular orbit)
- Visible matter alone: v should decline at large r
- Observed: v stays flat → need dark matter
- NFW profile: standard dark matter halo model
Instruction: Try setting the halo density to zero and watch the rotation curve fall off at large radii!