Observations of a complete sample of brightest cluster galaxies with multiple nuclei

Redshifts and stellar velocity dispersions are presented for a complete sample of multiple-nucleus brightest cluster galaxies (33 objects in 14 clusters) with z less than 0.05. In many cases there is sufficient signal to noise that velocities can be traced as a function of position along the slit. The distribution of multiple-nucleus velocities with respect to the central galaxy has an rms width of 800 km/s; approximately 65 percent of the nuclei have velocities greater than 300 km/s. To within the limited photometry available, the nuclei and central brightness cluster galaxies both follow the same luminosity-stellar velocity dispersion relationship as other elliptical galaxies. There are suggestive but statistically unreliable indications that (1) the distribution of nuclei velocities is bimodal, with a peak at zero velocity and a peak at 700 km/s; (2) low-mass nuclei typically do not have large velocities, and (3) central galaxies brighter than 2 L(star) have captured their low-velocity companions.