We present the results of a dynamical analysis of three rich , X-ray luminous galaxy clusters , Abell 222 , Abell 223 and Abell 520 , that are at intermediate redshifts .
Our study is based on radial velocities for 71 cluster members , respectively 30 for A222 , 20 for A223 and 21 for A520 , measured from spectra obtained at the Canada-France-Hawaii Telescope , the European Southern Observatory , and the Pic du Midi Observatory , and supplemented with radial velocities from the literature .
A222 galaxies have slightly higher velocities than those of A223 , with bi-weighted mean velocity of V _ { bi } = 64242 \pm 194 ~ { } { km s ^ { -1 } } for A222 , and of V _ { bi } = 63197 \pm 266 ~ { } { km s ^ { -1 } } for A223 .
The velocity dispersions of the two clusters are about the same : \sigma _ { bi } = 1013 \pm 150 ~ { } { km s ^ { -1 } } and \sigma _ { bi } = 1058 \pm 160 ~ { } { km s ^ { -1 } } for A222 and A223 , respectively .
For A520 we obtain V _ { bi } = 60127 \pm 284 ~ { } { km s ^ { -1 } } with \sigma _ { bi } = 1250 \pm 189 ~ { } { km s ^ { -1 } } .
We also give mass and mass-luminosities ratio estimates for each cluster separately .
We argue that these clusters are presently undergoing strong dynamical evolution and that A222 and A223 will probably merge in the future .
We have applied a Principal Component Analysis to a sample of 51 CFHT spectra to produce a spectral classification for these galaxies .
This classification has allowed us to show that the morphological and kinematical segregations were already established in these intermediate redshift clusters .