A Subaru Weak Lensing Survey I: Cluster Candidates and Spectroscopic Verification

TL;DR

This paper reports on a Subaru weak lensing survey that identified and spectroscopically confirmed 41 galaxy cluster candidates, demonstrating the effectiveness of weak lensing in constructing reliable cluster catalogs.

Contribution

First large-scale weak lensing survey with spectroscopic verification of cluster candidates, establishing the reliability of lensing-selected cluster catalogs.

Findings

Confirmed 41 galaxy clusters via spectroscopy.

High match rate (12/15) with X-ray detected clusters in XMM-LSS.

Weak lensing effectively identifies galaxy clusters regardless of galaxy or intracluster medium properties.

Abstract

We present the results of an ongoing weak lensing survey conducted with the Subaru telescope whose initial goal is to locate and study the distribution of shear-selected structures or halos. Using a Suprime-cam imaging survey spanning 21.82 square degree, we present a catalog of 100 candidate halos located from lensing convergence maps. Our sample is reliably drawn from that subset of our survey area, (totaling 16.72 square degree) uncontaminated by bright stars and edge effects and limited at a convergence signal to noise ratio of 3.69. To validate the sample detailed spectroscopic measures have been made for 26 candidates using the Subaru multi-object spectrograph, FOCAS. All are confirmed as clusters of galaxies but two arise as the superposition of multiple clusters viewed along the line of sight. Including data available in the literature and an ongoing Keck spectroscopic campaign, a total of 41 halos now have reliable redshifts. For one of our survey fields, the XMM LSS (Pierre et al. 2004) field, we compare our lensing-selected halo catalog with its X-ray equivalent. Of 15 halos detected in the XMM-LSS field, 10 match with published X-ray selected clusters and a further 2 are newly-detected and spectroscopically confirmed in this work. Although three halos have not yet been confirmed, the high success rate within the XMM-LSS field (12/15) confirms that weak lensing provides a reliable method for constructing cluster catalogs, irrespective of the nature of the constituent galaxies or the intracluster medium.