CL0238.3+2005 RTT-150 composite rizw image

We conclude that the merger axis is most likely neither close to the line of sight nor to the sky plane. We compare CL0238 with the two well-known clusters MACS0416 and the Bullet and conclude that CL0238 corresponds to an intermediate phase between the pre-merging MACS0416 cluster and the post-merger Bullet cluster. Namely, this cluster recently (only ~=0.1Gyr ago) experienced an almost head-on merger.

We argue that this "just after" system is a very rare case and an excellent target for lensing, the Sunyaev-Zeldovich effect, and X-ray studies that can constrain properties ranging from dynamics of mergers to self-interacting dark matter, and plasma effects in the intracluster medium that are associated with shock waves, for instance, electron-ion equilibration efficiency and relativistic particle acceleration.