090313

We propose a 122 ks XMM-Newton observation of the merging galaxy cluster MACS J1752+4440. The system is characterized by remarkable double bullets in X-ray and the symmetric giant double radio relics which together indicate a high-speed post-merger resembling the Bullet Cluster however observed at a later phase. This unique combination offers a rare opportunity to address long-standing puzzles in cluster mergers including generation/propagation of plasma shocks and particle acceleration. The observation will enable us to 1) measure X-ray shocks at the location of the relics 2) reveal thermodynamic properties of the double bullets 3) constrain the merger scenario and 4) quantify the re-acceleration efficiency of diffusive shock acceleration. [truncated! Please see actual data for full text]