MORPHOLOGY AND KINEMATICS IN CLUSTERS OF GALAXIES

The existence of subclustering, infall, and the morphology-local densi ty relation suggests that there should be differences in the kinematic s of different morphological populations in clusters. From published d ata, we compile a sample of galaxy redshifts and types in six rich clu sters of galaxies: A548, A1060, A1644, A1656, A2151, and DC 2048-52. I n three clusters, the velocity distribution of spiral galaxies is diff erent from those of other morphological populations: (1) spirals and e llipticals differ in A 1656 and A215 1, and (2) spirals and SO's diffe r in DC 2048 - 52. The differences in the distributions result primari ly from differences in the mean velocities. The results are consistent with a picture in which a cluster irregularly accretes clumps of most ly spiral galaxies from the field, causing the combined velocity distr ibution to be asymmetric. These clumps might infall within the plane o f a wall like the Great Wall of galaxies [Geller & Huchra, Science, 24 6, 897 (1989)]. Recent dynamical simulations show that the asymmetries may persist until after the clumps have merged with the central mass concentration [van Haarlem, PhD. thesis, Leiden University (1992)].