Our Galaxy (CP Fig 19.1a)
Our Galaxy (CP Fig 19.1b)
Orbits of stars (CP Fig 19.18)
Spectral lines viewed through diffraction grating
Redshift
Blueshift
Observing Galactic Rotation
The result: A rotation curve
NB, there is an overall net redshift due the the cosmic expansion.
Mass inferred from lensing: Must have dark matter
Theoretical studies of Galaxies
Images and movies from the Virgo consortium
Another Virgo Link
Galaxy collision movies