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”