The V magnitudes of the galaxies were measured using circular apertures with the radius at which the intensity gradient reached zero. Stars, multiple nuclei or other galaxies within the outline of the radio galaxy were removed, sustituting their counts by the mean intensity value in adjacent positions. The apparent V magnitudes, aperture radius, Vmagnitudes corrected for Galactic extinction and absolute magnitudes (without k and evolutionary corrections) are listed in Table 3. The main source of error in the apparent magnitudes is the zero-point photometric calibration, which is, in average, 0.05 mag. The classification of the galaxies as ellipticals (E), spirals (S) or irregulars (Irr), obtained from the contour plots, is also given in this table. In total 57 galaxies correspond to ellipticals, 6 to spirals (including a possible SO) and 7 to irregulars. Along with this classification we listed some additional remarks on the optical morphology of the ellipticals, like isophote distortions relative to an elliptical model, shells, tails, nuclear dust, a strong nucleus, or multiple nuclei. Some of these peculiarities (e.g. distorted morphology and presence of tails, shells or nuclear dust) are generally interpreted as signatures of gravitational interaction (Schweizer ). In Table 3 we also give information about the association with known cluster of galaxies (Abell or Zwicky clusters) or with dumbbell systems. Ten radio sources (14%) are located in clusters of galaxies of which 8 are the brightest cluster members (BCM) and one is the second ranked galaxy in the cluster (2nd BCM). Five radio sources (7%) belong to dumbbell systems and 2 appear to have multiple nuclei. A detailed and quantitative study of the environment of the complete B2 sample will be presented in a forthcoming paper.
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