A kinematic search for bound populations around brightest cluster members in a sample of 52 clusters of galaxies

We measured the radial velocities of 265 galaxies in the field of 52 clusters in the redshift range 0.05 < z < 0.25. In a 93% complete sample of galaxies close to the brightest cluster members (BCMs; d < 40 kpc) we found that the percentage (43 +/- 9%) of galaxies with \dV\ < 300 km s(-1) is higher than the one (28 +/- 4%) of a control sample of more distant galaxies. Moreover, we found that the velocity dispersion (576(-77)(+68)) km s(-1)) of the galaxies in the inner sample is lower than the one (866(-55)(+52) km s(-1)) of the control sample. The sample's velocity dispersion is also lower than the expectation from the Dt of the velocity dispersion profile of all data combined in a pseudocluster with dynamical models of the cluster mass distribution. We discuss these results in the light of the existence of a bound population of galaxies that will eventually merge with the BCM as a general feature of clusters of galaxies.