(Proposal ID) S17A-124

(PI) Chan, HungHsu

(Proposal Title)
Lensed quasars from Hyper Suprime-Cam survey: Spectroscopic confirmation

(Abstract)
Strong gravitationally lensed quasars provide powerful means to study galaxy 
evolution and cosmology. However, the number of lensed quasars, especially 
those with four quasar images known as "quads", with good ancillary data is 
limited. We have searched through SDSS photometry and the Hyper Suprime-Cam 
(HSC) Strategic Program (SSP) observations, and identified three promising 
quad lens candidates for spectroscopic follow-up confirmation given the 
restrictions on the target observability. The confirmation will lend credence 
to the lensing hypothesis and allow extraction of physical quantities of the 
lens system (such as the lens galaxy mass) via the proposed redshift 
measurements. Given that there are currently only a few quad quasar systems 
with good ancillary data, our quad candidates would augment substantially 
the existing sample. As part of the pilot lensed-quasar follow-up program of 
the HSC SSP observations, the results of this proposal will allow us to enhance
further our search algorithm on future HSC SSP data for the discovery of new 
HSC lensed quasars. We request 1.5 nights with FOCAS in the MOS mode to confirm
the lensing nature of our three promising quad candidates.