White Paper: Radio Emission and Polarization Properties of Galaxy
  Clusters with VLASS
  We outline the science case for extended radio emission and polarization in
galaxy clusters which would be a scientifically important area of research for
an upcoming Jansky Very Large Array Sky Survey. The survey would provide a
major contribution in three key areas of the physics of clusters: 1) the active
galactic nucleus population and the impact of feedback on the evolution of the
intra-cluster medium, 2) the origin and evolution of diffuse cluster radio
sources to probe the physics of mergers with implications for cosmology, and 3)
the origin and role of magnetic fields in the ICM and in large scale
structures. Considering all three areas, a survey must have sufficient spatial
resolution to study the tailed galaxies which trace the cluster weather as well
as the radio lobes driving energy into the cluster from the central AGN. The
survey must also have sensitivity to low surface brightness emission and large
angular scales to probe radio halos and relics as well as the WHIM residing in
the large scale structure filaments. Finally, we note that full polarization
information would be a highly valuable tool to probe a number of
cluster-related issues. Due to the general steep spectral index of the emission
we consider the survey is best suited to this science when conducted in P, L,
or S bands. We conclude that the choices of S Band + D Configuration, L Band +
C Configuration, and P Band + B Configuration offer optimal resolutions for
constraining galactic interactions and feedback in cluster environments, while
still probing large scale structure and the bulk cluster environment itself.
While the push to probe higher redshifts and lower mass limits strongly favors
a narrow and deep (or even targeted) survey strategy, we note that a wide
survey covering roughly 1/4-2/3 of the sky will have significant scientific
return, discovery potential, and archival value.
