XMM-Newton observes Cl J0152.7-1357:: A massive galaxy cluster forming at merger crossroads at z=0.83

We present an analysis of a 50 ks XMM- Newton observation of the merging galaxy cluster Cl J0152.7 similar to 1357 at z = 0: 83. In addition to the two main subclusters and an infalling group detected in an earlier Chandra observation of the system, XMM- Newton detects another group of galaxies possibly associated with the cluster. This group may be connected to the northern subcluster by a filament of cool ( 1: 4 (+0.3)(-0.1) keV) X- ray-emitting gas and lies outside the estimated virial radius of the northern subcluster. The X- ray morphology agrees well with the projected galaxy distribution in new K-band imaging data presented herein. We use detailed spectral and imaging analysis of the X- ray data to probe the dynamics of the system and find evidence that another subcluster or group has recently passed through the northern subcluster. Cl J0152.7 - 1357 is an extremely dynamically active system, with mergers at different stages occurring along two perpendicular merger axes.