Luminosity Distributions -- Bulges
Elliptical galaxies have an apparently simple
structure, can be characterized by their luminosity
distribution.  Maximum in center, and falls off:
Hubble’s Law:
I/I0 = [(r/a) + 1] -2
De Vaucouleur’s r1/4 Law:
Log (I/Ie) = -3.33[(r/re)1/4 – 1]