Hundreds of weak lensing shear-selected clusters from the Hyper Suprime-Cam Subaru Strategic Program S19A data

TL;DR

This study constructs a large sample of shear-selected galaxy clusters from the Hyper Suprime-Cam data, demonstrating high purity and potential for cosmological and astrophysical research.

Contribution

It presents a method to identify shear-selected clusters using weak lensing maps, expanding the sample size and optimizing detection techniques.

Findings

Constructed a catalog of 187 shear-selected clusters with >95% purity.

Expanded the sample to 418 clusters by optimizing filter functions.

Demonstrated the effectiveness of weak lensing for unbiased cluster detection.

Abstract

We use the Hyper Suprime-Cam Subaru Strategic Program S19A shape catalog to construct weak lensing shear-selected cluster samples. From aperture mass maps covering $\sim 510$~deg$^2$ created using a truncated Gaussian filter, we construct a catalog of 187 shear-selected clusters that correspond to mass map peaks with the signal-to-noise ratio larger than 4.7. Most of the shear-selected clusters have counterparts in optically-selected clusters, from which we estimate the purity of the catalog to be higher than 95\%. The sample can be expanded to 418 shear-selected clusters with the same signal-to-noise ratio cut by optimizing the shape of the filter function and by combining weak lensing mass maps created with several different background galaxy selections. We argue that dilution and obscuration effects of cluster member galaxies can be mitigated by using background source galaxy samples and adopting the filter function with its inner boundary larger than about $2'$. The large samples of shear-selected clusters that are selected without relying on any baryonic tracer are useful for detailed studies of cluster astrophysics and cosmology.