The ACS Fornax Cluster Survey. II. The Central Brightness Profiles of Early-Type Galaxies: A Characteristic Radius on Nuclear Scales and the Transition from Central Luminosity Deficit to Excess
Résumé
We analyze brightness profiles for 143 early-type galaxies in the Virgo and Fornax Clusters, observed with the Advanced Camera for Surveys on the Hubble Space Telescope. Sérsic models are found to provide accurate representations of the global profiles with a notable exception: the observed profiles deviate systematically inside a characteristic ``break'' radius of Rb~0.02+0.025-0.01Re, where Re is the effective radius of the galaxy. The sense of the deviation is such that bright galaxies (MB~-19 galaxies may be the analogs of the dense central cores predicted by some numerical simulations to form via gas inflows.