NECSUS : Subaru/HSC Weak-lensing Analysis of Very Nearby Galaxy Clusters

Nobuhiro Okabe

We carry out weak-lensing analysis of galaxy clusters at z<0.06 using a new prime focus camera, Hyper Suprime-Cam (HSC), of the Subaru telescope. Weak-lensing analysis is a powerful and unique tool to derive cluster masses without any assumptions of dynamical states, which is complementary to X-ray analysis to estimate hydrostatic equilibrium masses.The extremely wide field-of-view of HSC is the best instrument to cover the entire region of the very nearby clusters by one pointing.Weak-lensing analysis for the very nearby clusters offers three important advantages. First, the large apparent area provides us with a correspondingly large number of background galaxies, which leads to low statistical errors, compensates for low lensing efficiency and achieves a high signal-to-noise ratio. Second, the large apparent size enables us to easily resolve the truncation radii for less massive subhalos and measure their masses. Third, a contamination of member galaxies are negligible in background shear catalog compared to weak-lensing studies at z~0.2.We have launched the new project, NECSUS(NEarby Cluster SUrvey with Subaru), to compile the 22 clustersusing multi-wavelength data-sets. We present weak-lensing results for the sub-sample of clusters and constrains on the non-thermal pressure component of the intracluster medium by joint WL and X-ray studies.