(Proposal ID) S10A-083

(PI) Glazebrook, Karl

(Proposal Title)
Is Dark Energy an Illusion? Measuring the growth of structure to z=1.5

(Abstract)
We wish to secure vital z'-band imaging over 50 deg2 (25 deg2 in S10A) to 
enable cosmological redshift surveys using FMOS and perform the first 
comprehensive and deep weak lensing survey using Subaru. This will provide two 
independent measures of the growth of structure over 0 < z < 1.5 ensuring a 
redshift baseline sufficient to provide the first convincing test of 
alternative theories of gravity as an explanation for the accelerating 
Universe. FMOS is most efficient for spectroscopy for emission line galaxies 
at z ~ 1.5 however selecting them requires wide-area z'-band data which does 
not exist. Using the unique red sensitivity of SuprimeCam's new detectors we 
will augment the existing deep u' g' r' i' data from the CFHTLS MegaCam Wide 
Survey to simultaneously provide photometry for FMOS targets and to measure 
weak lensing shear to significantly higher redshifts (z > 1) than current 
work. The MegaCam fields have extensive auxiliary spectroscopic and 
photometric data thus maximizing the broader impact of the Subaru data. 
This new imaging is the vital first step for establishing Subaru Telescope 
as the premiere world facility for doing cosmology in the z > 1 Universe.