Weak radio galaxies .1. Broad-band optical imaging

We report on a study of the optical properties of weak radio galaxies (WRGs) from the B2 survey, to obtain the broad-band photometric properties and morphology information crucial for our narrow-band imaging at Her and [O III] study (Carrillo et al. 1997). This paper contains optical CCD images of 30 radio galaxies obtained at V, R and I. We present the morphological and photometric results and discuss their relationship to the radio structure and environmental properties. We find that most WRGs are E galaxies, have peculiar morphologies and are located in high galaxy density environments. Optical colors of WRGs are unusual if compared to colors of normal ellipticals, but similar to AGN colors. The surface brightness profiles of most WRGs follow the de Vaucouleurs law expected for ellipticals at most radii, but in all cases a turnover or flatness is observed in the innermost portion of the profiles, possibly produced by an additional nuclear emission source. The tidal effects produced by galaxy companions described by Kormendy (1977) for ellipticals, are clearly evident in the outer parts of the WRGs profiles and can be associated to interaction effects.