The structure of brightest cluster members. I - Surface photometry

Abstract

Faint surface photometry of bright ellipticals in the cores of galaxy clusters, combined with photometry from the literature, have been used to produce a sample of 261 ellipticals in 63 clusters over the M(V) magnitude range of -18 to -25. The observation and reduction procedures are described, and an analysis of the surface brightness profiles with respect to fitting functions and empirical structural parameters is presented. The structural properties of cD galaxies and other brightest cluster members (BCMs) are compared with those of normal ellipticals. It is found that the r to the 1/4th law provides a reasonably good description of the structure of ellipticals only for a narrow range of surface brightnesses and a limited range of luminosities. Fits to the r to the 1/4th and Hubble-Oemler laws show a clear difference between BCMs and normal ellipticals.