BRIGHTEST CLUSTER GALAXY PROFILE SHAPES

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