Ay 124		Homework #4	    Due on Thursday, March 1
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Read everything you can on the topics of galaxy classification, 
manifolds, Hubble sequence, dwarfs, light distributions, and 
luminosity functions. 

1.  Write TWO reports in the usual format (size ~ 1 - 2 typed 
    pages or equivalent) on two papers of your choice from that 
    list of topics, but the two topics ought to be different.

2.  Generate "surface brightness" profiles, corresponding to
    the following formulae:  (1) Exponential, (2) Hubble law,
    (3) de Vaucouleurs' law, (4) Gaussian.  For each of them,
    plot log(surf.br.) vs. (a) linear radius, (b) log(radius),
    (c) radius to the 1/4 power.  Your profiles should cover
    about 3 - 4 decades in surface brightness.