On broken structural and dynamical homology of elliptical galaxies: a Virgo-Fornax distance modulus

This paper presents an extension to the work of D'Onofrio et al. (1997) on the Fundamental Plane (FP), in which a distance modulus between the Virgo and Fornax clusters was derived. In addressing the broken dynamical homology, implied by the broken structual homology (Caon, Capaccioli & D'Onofrio 1993; Graham et al. 1996), the resulting FP that is constructed is found to more closely resemble the plane predicted from the virial theorem. Using the FP as a distance estimator, the Virgo-Fornax distance modulus is reduced from +0.45±16 mag to +0.25±0.12 mag when the influence of broken dynamical homology is incorporated.