Analysis of new WHT, VLT, and SOAR observations: Confirming new galaxy clusters from Planck & Calibrating the masses of high-redshift SPT clusters via weak gravitational lensing for cosmological investigations

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We request DFG funding to conduct the scientific analysis of new observational data targeting massive high-redshift galaxy clusters and cluster candidates. These observations were obtained by the applicant as Principal Investigator via competitive international calls for open telescope time on major astronomical facilities. We will use our WHT observations to confirm new cluster candidates from the Planck Sunyaev-Zel’dovich (SZ) survey and to measure their redshift and richness.Our new VLT and SOAR observations, as well as complementary HST data, target massive high-redshift galaxy clusters from the South Pole Telescope (SPT) SZ survey. The analysis of these observations will allow us to calibrate the mass scale of massive distant clusters empirically via the measurement of weak gravitational lensing (WL) image distortions. These distortions are imprinted onto the shapes of background galaxies when their light bundles pass through the gravitational potential of the clusters.Our analysis will yield the tightest currently available cluster mass calibration at redshift z~0.9, and the first mass calibration for SZ clusters at z>1.2. These constraints will provide the missing piece that will allow us to simultaneously improve dark energy constraints from the SPT cluster sample and our understanding of the astrophysics of massive high-redshift galaxy clusters.