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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]