Properties of Galaxies
Distance
Use Cepheid Variables for close objects
Other objects for which Absolute Magnitude is known:
Supernova
Planetary nebula in certain emission lines
Use “Hubble Law” for more distant objects
(Correlation of distance with radial velocity)
Diameter and Luminosity
Obtain from angular size and magnitude, combined with distance
Mass
Rotation curves
Velocity dispersion
90 to 99% of mass is
“dark matter”