| Abstract: |
Strong gravitational lens systems with measured time delays between the multiple images can be used to determine the ʺtime-delay distanceʺ to the lens, which is primarily sensitive to the Hubble constant. I will present the first results of an international program to analyze a sample of five strongly lensed quasars with the goal of measuring the Hubble constant to <4% in precision. Current and upcoming imaging surveys including the HSC survey will contain thousands of new lensed quasars, augmenting the existing sample by at least two orders of magnitude. To find such lens systems, we have built a robot, CHITAH, that hunts for lensed quasars by modeling the configuration of the multiple quasar images. I will show the performance of CHITAH based on tests using simulated lens systems and a real lens system. The search for lensed quasar candidates in HSC is underway. I will describe practical ways to follow up the lens candidates and the bright prospects of gravitational lens time delays as an independent and competitive cosmological probe. |
