报告题目：Strong Gravitational Lensing as a Probe of Galaxy Evolution and Cosmology

报  告  人：Kenneth C. Wong, National Astronomical Observatory of Japan

报告时间：2018-01-19 14:00

报告地点：蒙民伟科技南楼 S727

报告摘要：Strong gravitational lensing is sensitive to the total mass distribution along a particular line of sight in the Universe, making it a unique probe of dark matter in lensing galaxies. However, strong lenses are quite rare and require deep wide-area imaging surveys to build up a statistical sample. The ongoing Hyper-Suprime Cam survey will cover 1400 deg^2 of the sky to a depth of r~26. I present the current progress of the survey and various projects within the strong lensing working group, which are focused on both discovering new lenses and leveraging these systems for studies of galaxy structure and cosmology. Searches for lensed quasars are particularly valuable because they are variable and can be monitored to measure the "time delay" between the multiple images, which is sensitive to the Hubble constant (H0). This is key to probing dark energy, neutrino physics, and the spatial curvature of the Universe. I discuss the H0 Lenses In COSMOGRAIL’s Wellspring (H0LiCOW) project, which aims to measure H0 to<3.5% precision from five lensed quasars using a wide range of observational data. The most recent H0LiCOW analysis of the first three lenses constrains H0 to ~3.8% precision for a flat Lambda CDM cosmology. These results are consistent with independent determinations of H0 using the distance ladder method and are in moderate tension with the latest Planck results for a similar cosmology, hinting at possible new physics beyond the standard LCDM model and highlighting the importance of this independent probe.