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 Sérsic 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 Sérsic parameters for a set of high-resolution LCDM halos spanning a wide range in mass. The mean Sérsic 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.
Department, Program, or Center
School of Physics and Astronomy (COS)
Astrophys.J. 624 (2005) L85-L88
RIT – Main Campus