Density-Dependent Luminosity Functions for Galaxies in the Las Campanas   Redshift Survey
  Galaxies in the Las Campanas Redshift Survey are classified according to their spectra, and the resulting spectral types are analyzed to determine if local environment affects their properties. We find that the luminosity function of early-type objects varies as a function of local density. Our results suggest that early-type galaxies (presumably ellipticals and S0's) are, on average, fainter when they are located in high-density regions of the Universe. The same effect may operate for some, but not all, late-type galaxies. We discuss the implications of this result for theories of galaxy formation and evolution. 
Benjamin C. Bromley, William H. Press, Huan Lin, Robert P. Kirshner