Some effects of galaxy structure and dynamics on the Fundamental Plane – II. A Virgo–Fornax distance modulus

The influence of broken structural homology, and the implied broken dynamical homology, is examined for the Fundamental Plane (FP). Requiring a symmetrical treatment of the FP variables, a bisector method of linear regression was applied, in 3-dimensions, to derive the best FP. A bootstrapping procedure has been used to estimate the uncertainties associated with the slope of the FP. For 25 E and S0 Virgo galaxies, the ‘standard’ FP, constructed using R 1/4 model parameters for the effective radii (Re,4) and the mean surface brightness within this radius (�e,4) and using central velocity dispersion (CVD) measurements (�0), gave a relation described by Re,4 / � 1.10±0.14 0 �