The Luminosity Function of Galaxies as modelled by the Generalized Gamma
  Distribution
  Two new luminosity functions of galaxies can be built starting from three and
four parameter generalized gamma distributions. In the astrophysical
conversion, the number of parameters increases by one, due to the addition of
the overall density of galaxies. A third new galaxy luminosity function is
built starting from a three parameter generalized gamma distribution for the
mass of galaxies once a simple nonlinear relationship between mass and
luminosity is assumed; in this case the number of parameters is five because
the overall density of galaxies and a parameter that regulates mass and
luminosity are added. The three new galaxy luminosity functions were tested on
the Sloan Digital Sky Survey (SDSS) in five different bands; the results always
produce a "better fit" than the Schechter function. The formalism that has been
developed allows to analyze the Schechter function with a transformation of
location. A test between theoretical and observed number of galaxies as a
function of redshift was done on data extracted from a two-degree field galaxy
redshift survey.
