Environmental Effects on Clusters at z=0.2: Strong Galaxy Disruption in A2667 and A1689.

We show first results on the study of two spiral galaxies in the process of being strongly disrupted in the rich Abell clusters A1689 (z=0.18) and A2667 (z=0.23). Hubble Space Telescope images show a spectacular rupture of the spiral arms in both galaxies, one of which appears with no obvious neighbor. Extended trails composed by blue bright knots are associated with both systems. The extraordinary features observed in these two galaxies indicate that gravitational interactions are not rare in medium redshift clusters. The mean ages of the knots, between 10 Myr and 1 Gyr, suggest a tidal interaction scenario where the knots had been stripped from their parent galaxy. [ABSTRACT FROM AUTHOR]