A Large Massive Quiescent Galaxy Sample at z~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 4000A Balmer jump in
passive galaxies to the highest redshift possible within the survey. With the
rich multi-wavelength 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_sun)>10.5, with a median of log(M*/M_sun)=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 statistical significant sample of massive galaxies in a
relative narrow redshift range. Our sample is 7-20 times larger at the massive
end (log(M*/M_sun)>10.5) than any existing samples obtained in previous
surveys. This is a pioneer study, and the technique introduced here can be
applied to future wide-field survey to study large scale structure, and to
identify high density region and clusters.
