Unveiling Cosmic Structure Formation by Cluster Lensing

In this talk, I will discuss how cluster gravitational lensing can be used to test models of cosmic structure formation in
combination with multiwavelength observations and numerical simulations.  The topics of my talk will include (1) observational constraints on the cluster mass distribution from weak and strong lensing, (2) recent observational attempts to detect and characterize the steepening splashbak feature in cluster outskirts, (3) our recent discovery of the cluster halo fundamental plane from combined lensing and X-ray observations (Fujita, Umetsu e tal. 2018a, 2018b), and (4) tests of LCDM predictions using cluster shapes (CLUMP-3D).  All these topics are highly relevant to large-scale accretion physics, or the mass assembly histories of galaxy clusters in connection with their　large-scale environments.