The fundamental plane of radio galaxies

We collected photometrical and dynamical data for 73 low red-shift (z <0.2) Radio Galaxies (LzRG) in order to study their Fundamental Plane (FP). For 22 sources we also present new velocity dispersion data that complement the photometric data given in our previous study of LzRG (Govoni et al. 2000a) . It is found that the FP of LzRG is similar to the one defined by non-acti ve elliptical galaxies, with LzRG representing the brightest end of the pop ulation of early type galaxies. Since the FP mainly reflects the virial equ ilibrium condition, our result implies that the global properties of early{ type galaxies (defining the FP) are not influenced by the presence of gas a ccretion in the central black hole. This is fully in agreement with the rec ent results in black hole demography, showing that virtually all luminous s pheroidal galaxies host a massive black hole and therefore may potentially become active. We confirm and extend to giant ellipticals the systematic in crease of the mass-to-light ratio with galaxy luminosity.