In collaboration with UK astronomers Mike Merrifield, Irini Sakelliou, Nick Drake, Trevor Ponman, David Acreman, Stevens, I am searching for X-ray wakes in clusters of galaxies.  We have focused on the z=0.045 cluster Abell 160 for a study using first ROSAT (Drake et al 2000,), and then Chandra X-ray images (in preparation).   The goal was to find numerous wakes in one cluster and constrain the kinematics by taking the wake/tail direction as an indicator of the direction of motion. 
The wake phenomenon is poorly understood and a statistical sample of clusters with both X-ray and optical imaging is badly needed.   To this end, I have been gathering CCD data of promising wake clusters (selected by Tx and Lx and tailed radio sources) at MDM. The optical imaging will allow a comparison of X-ray wake strength with galaxy luminosity, morphology, etc.

This work has included a preliminary archival search for wake candidates in the ROSAT archive. Here is an example of a cluster with interesting X-ray and optical coincidences, Abell 194. Squares indicate cluster members with redshifts.