On the shape of luminosity profiles of dwarf galaxies as a distance indicator: The NGC 5044 Group revisited

Conflicting evidence has been recently raised in order to use surface brigh tness profiles of dwarf galaxies as a distance indicator. In this paper we discuss in some detail the main error sources in profile fitting procedures for galaxies with more than one physical component, showing their impact o n the resulting shape parameters. The apparent tight coupling between shape parameter and (pseudo) scalelength in the Sersic law is especially dealt w ith, demonstrating that this relationship is mostly a mathematical artifact . thus throwing doubts on its usefulness as a distance indicator. Galaxies departing from the luminosity-shape relation are shown to exhibit different kinds of intrinsic peculiarities, thus prompting for better securing the e mpirical constraints to conform observational samples. As a relevant exampl e in this sense new observations of the galaxy N50 in the NGC 5044 Group ar e presented. We show that this object may be at an intermediate evolutionar y stage between blue compact dwarfs (BCDs) and dwarf ellipticals (dEs).