Inside a Beehive: the Multiple Merging Processes in the Galaxy Cluster Abell 2142

Understand

To investigate the dynamics of the galaxy cluster A2142, we compile an extended catalog of 2239 spectroscopic redshifts of sources, including newly measured 237 redshifts, within 30 arcmin from the cluster center.

• With the $\sigma$-plateau algorithm from the caustic method, we identify 868 members and a number of substructures in the galaxy distribution both in the outskirts, out to $\sim$3.5 Mpc from the cluster center, and in the central region.
• In the outskirts, one substructure overlaps a falling clump of gas previously identified in the X-ray band.
• These substructures suggests the presence of multiple minor mergers, which are responsible for the complex dynamics of A2142, and the absence of recent or ongoing major mergers.