  We propose that synchronized triggering of star formation in gas-rich
galaxies is possible during major mergers of cluster of galaxies, based on new
numerical simulations of the time evolution of the physical properties of the
intracluster medium (ICM) during such a merger event. Our numerical simulations
show that the external pressure of the ICM in which cluster member galaxies are
embedded, can increase significantly during cluster merging. As such, efficient
star formation can be triggered in gas-rich members as a result of the strong
compression of their cold gas by the increased pressure. We also suggest that
these star-forming galaxies can subsequently be transformed into poststarburst
galaxies, with their spatial distribution within the cluster being different to
the rest of its population. We discuss whether this possible merger-induced
enhancement in the number of star-forming and post-star-forming cluster
galaxies is consistent with the observed evolution of galaxies in merging
clusters.
