  We explore similarities in the luminosity distribution of early type galaxies
and the mass profiles of LCDM halos. The spatial structure of these systems may
be accurately described by a simple law where the logarithmic slope of the
projected density is a power law of radius; the Sersic law. We show that this
law provides a significantly better fit than a three-parameter generalization
of the NFW profile and derive the best-fitting Sersic parameters for a set of
high-resolution LCDM halos spanning a wide range in mass. The mean Sersic n
values are 3.0 for dwarf- and galaxy-sized halos and 2.4 for cluster-sized
halos, similar to the values that characterize luminous elliptical galaxies. We
discuss possible reasons why the same law should describe dark and luminous
systems that span a range of over seven decades in mass.
