A Tale of Two Telescopes: Joint X-ray Analyses of High Redshift Galaxy Clusters

The hot intracluster medium (ICM) is a direct probe of the dynamic and thermodynamic state of galaxy clusters and groups. To fully understand the history of feedback due to star formation and AGN activity, we require X-ray measurements of the density, temperature and metallicity distributions in these objects. In this talk, we present an analysis of more than 20 clusters at high redshifts, 0.7 < z < 1.7, selected through Sunyaev-Zel'dovich (SZ) effect surveys, and observed with both the XMM-Newton and Chandra satellites. For each cluster, we extract a precise gas mass profile and determine spatially resolved temperature and metallicity measurements. Our analysis provides the most precise measurement of the bulk metallicity of the ICM to date, and the first observational evidence for the metallicity decreasing as we approach the epochs of peak star formation and AGN activity. Our measurements of the thermodynamic profiles for these clusters exhibit remarkably small intrinsic scatter after scaling for redshift-dependent evolution, providing evidence for strong self-similarity in cluster evolution out to high redshifts. This work highlights the synergistic strengths of current flagship X-ray observatories to probe the faint, high-redshift universe. Future SZ surveys will greatly expand the number of high-z clusters available for study. X-ray missions providing both high spatial resolution and exquisite soft X-ray sensitivity will be needed to explore these systems efficiently.