Probing Primordial Non-Gaussianity with Weak Lensing Minkowski
  Functionals
  We study the cosmological information contained in the Minkowski Functionals
(MFs) of weak gravitational lensing convergence maps. We show that the MFs
provide strong constraints on the local type primordial non-Gaussianity
parameter f_NL. We run a set of cosmological N-body simulations and perform
ray-tracing simulations of weak lensing, to generate 100 independent
convergence maps of 25 deg^2 field-of-view for f_NL = -100, 0 and 100. We
perform a Fisher analysis to study the degeneracy among other cosmological
parameters such as the dark energy equation of state parameter w and the
fluctuation amplitude sigma_8. We use fully nonlinear covariance matrices
evaluated from 1000 ray-tracing simulations. For the upcoming wide-field
observations such as Subaru Hyper Suprime-Cam survey with the proposed survey
area of 1500 deg^2, the primordial non-Gaussianity can be constrained with a
level of f_NL ~ 80 and w ~ 0.036 by weak lensing MFs. If simply scaled by the
effective survey area, a 20000 deg^2 lensing survey using Large Synoptic Survey
Telescope will give constraints of f_NL ~ 25 and w ~ 0.013. We show that these
constraints can be further improved by a tomographic method using source
galaxies in multiple redshift bins.
