Peaks in weak lensing mass maps for cluster astrophysics and cosmology

Clusters of galaxies can be identified from peaks in weak lensing aperture mass maps constructed from weak lensing shear catalogs. Such purely gravitational cluster selection considerably differs from traditional cluster selections based on baryonic properties of clusters. In this review, we present the basics and applications of weak lensing shear-selected cluster samples. Detailed studies of baryonic properties of shear-selected clusters shed new light on cluster astrophysics. The purely gravitational selection suggests that the selection function can be quantified more easily and robustly, which is crucial for deriving accurate cosmological constraints from the abundance of shear-selected clusters. The recent advance of shear-selected cluster studies is driven by the Subaru Hyper Suprime-Cam survey, in which more than 300 shear-selected clusters with the signal-to-noise ration greater than 5 are identified. It is argued that various systematic effects in the cosmological analysis can be mitigated by carefully choosing the set-up of the analysis, including the choice of the kernel functions and the source galaxy sample.