A Large Massive Quiescent Galaxy Sample At Z Similar To 1.2

In this paper we present a simple color-magnitude selection and obtain a large sample of 33,893 massive quiescent galaxies at intermediate redshifts (1 < z < 1.5). We choose the longest wavelength available in the Hyper-Supreme-Cam (HSC) deep survey, the Y band and i - Y color, to select the 4000 angstrom Balmer jump in passive galaxies to the highest redshift possible within the survey. With the rich multiwavelength data in the HSC deep fields, we then confirm that the selected galaxies are in the targeted redshift range of 1 < z < 1.5, lie in the passive region of the UVJ diagram, and have high stellar masses at log(M-*/M-circle dot) > 10.5, with a median of log(M-*/M-circle dot) = 11.0. A small fraction of our galaxies is also covered by the HST CANDELS. Morphological analysis in the observed H band shows that the majority of this subsample are early-type galaxies. As massive early-type galaxies trace the high-density regions in the large-scale structure in the universe, our study provides a quick and simple way to obtain a statistically significant sample of massive galaxies in a relatively narrow redshift range. Our sample is 7-20x larger at the massive end (log(M-*/M-circle dot) > 10.5) than any existing samples obtained in previous surveys. This is a pioneer study, and the technique introduced here can be applied to a future wide-field survey to study large-scale structure and to identify high-density regions and clusters.