Merging Cluster Collaboration: Optical and Spectroscopic Survey of a
  Radio-Selected Sample of Twenty Nine Merging Galaxy Clusters
  Multi-band photometric and multi-object spectroscopic surveys of merging
galaxy clusters allow for the characterization of the distributions of
constituent dark matter and galaxy populations, constraints on the dynamics of
the merging subclusters, and an understanding of galaxy evolution of member
galaxies. We present deep photometric observations from Subaru/SuprimeCam and a
catalog of $\sim$5400 spectroscopic cluster members from Keck/DEIMOS across 29
merging galaxy clusters ranging in redshift from $z=0.07$ to $0.55$. The
ensemble is compiled based on the presence of radio relics, which highlight
cluster scale collisionless shocks in the intra-cluster medium. Together with
the spectroscopic and photometric information, the velocities, timescales, and
geometries of the respective merging events may be tightly constrained. In this
preliminary analysis, the velocity distributions of 28 of the 29 clusters are
shown to be well fit by single Gaussians. This indicates that radio relic
mergers largely occur transverse to the line of sight and/or near apocenter. In
this paper, we present our optical and spectroscopic surveys, preliminary
results, and a discussion of the value of radio relic mergers for developing
accurate dynamical models of each system.
