What Can We Learn From Roman Space Telescope Observations of eRosita Galaxy Clusters?

The combination of unprecedented resolution of eRosita images of x-ray gas structure in a large number of galaxy clusters, and Hubble-like high-resolution infrared imagery and grism spectroscopy of fields 100 times larger than that of the HST which will be enabled by the Nancy G. Roman Space Telescope will afford us a greater opportunity to examine the multiwavelength structure and kinematics of a larger number of galaxy clusters, for the cluster member galaxies, their cluster environments, and the larger-scale environments of the clusters themselves. This will provide better clues to various facets of the physical nature of a larger number of clusters such as kinematics and morphology of the clusters and the spatial distribution and kinmematics of the individual member galaxies of the clusters related to the spatial distribution and properties of cluster x-ray gas. It may also help reveal other evolutionary properties of clusters and of various individual galaxies in each cluster for clusters at different redhsifts such as colors of galaxies as a proxy for star-formation histories and stellar populations in the spatial context of the distribution of cluster x-ray gas. Such more detailed multiwavelength studies of a larger number of galaxy clusters may also help give a better understanding and calibration of measurements of cluster masses, and may aid in better characterizing phenomena such as lensing, the S-Z Effect and the implications for cosmology, among other things.