(Proposal ID) S15A-118

(PI) Dahle, Hakon

(Proposal Title)
 Joint lensing and X-ray study of the most massive galaxy clusters at z > 0.5.

(Abstract)
An integral part of the ESA Planck mission has been to conduct an all-sky 
survey for the most massive galaxy clusters in the Universe at redshifts up to 
1, by measuring the Sunyaev-Zel'dovich (SZ) effect. We propose deep Suprime-Cam
 imaging for weak gravitational lensing measurements of the total masses and 
mass profiles of a new, representative sample of massive, SZ-selected clusters 
at z>0.5 from Planck. Complementary X-ray observations have been obtained as 
part of an XMM-Newton Large Programme, allowing us to probe the relative 
distribution of X-ray luminous gas and dark matter and calibrate the 
relationship between baryonic observables and lensing cluster mass at z>0.5. 
This calibration is absolutely essential for cosmological applications of the 
SZ-selected clusters from Planck. Furthermore, the proposed observations will 
for the first time provide lensing-based measurements of the radial mass 
distribution for a representative sample of very massive clusters at z>0.5, 
selected with minimal bias regarding the dynamical state of the clusters. 
Comparison of these results with predictions from theory and simulations will 
provide an important test of the LambdaCDM paradigm.  High image quality, wide 
field and depth make Subaru/Suprime-Cam uniquely suited for this program.