Brightest cluster galaxy profile shapes

Abstract

We model the surface brightness profiles of a sample of 119 Abell brightest cluster galaxies (BCGs), finding a generalized de Vaucouleurs R^1/n^ law, where n is a free parameter, to be appropriate. Departures from the R^1/4^ law are shown to be a real feature of galaxy profiles and not due to observational errors or coupling of n with the other model parameters. BCGs typically have values of n greater than 4. The shape parameter n is shown to correlate with effective half-light radius, such that the larger BCGs have larger values of n. This continues a trend noticed amongst ordinary elliptical galaxies and dwarf elliptical galaxies, such that the brighter galaxies have larger values of n.