086251

A remarkable recent development is the discovery of cold fronts at very large radii in the Perseus cluster comma that are much older than those in cluster cores. Because of this comma diffusion processes have had much longer to broaden the edge comma while instabilities have had longer to grow. Recently we extended the XMM mosaic of Perseus to reach the virial radius to the west comma and have confirmed suggestions from ROSAT that the sloshing extends to the virial radius. Remarkably comma our new XMM mosaic shows 2 edges near the virial radius. However we are only seeing a small section of themdoublePoint the full scale of the sloshing is yet to be revealed. We propose 4 observations to extend the Perseus mosaic to fully cover the sloshing near the virial radius comma and fully reveal the extent of the mysterious double edge.