Kinematics, abundances and origin of brightest cluster galaxies

We present kinematic parameters and absorption line strengths for three bri ghtest cluster galaxies, NGC 6166, 6173 and 6086. We find that NGC 6166 has a velocity dispersion profile which rises beyond 20 arcsec from the nucleu s, with a halo velocity dispersion in excess of 400 km s(-1). All three gal axies show a positive and constant h(4) Hermite moment. The rising velocity dispersion profile in NGC 6166 thus indicates an increasing mass-to-light ratio. Rotation is low in all three galaxies, and NGC 6173 and 6086 show po ssible kinematically decoupled cores. All three galaxies have Mg-2 gradient s similar to those found in normal bright ellipticals, which are not steep enough to support simple dissipative collapse models, but these could be ac companied by dissipationless mergers which would tend to dilute the abundan ce gradients. The [Mg/Fe] ratios in NGC 6166 and 6086 are higher than that found in NGC 6173, and if NGC 6173 is typical of normal bright ellipticals, this suggests that cDs cannot form from late mergers of normal galaxies.