Speaker
Description
The accelerating expansion of the universe is one of the most mysterious phenomena. Cosmic acceleration implies the existence of dark energy or the breakdown of Einstein’s general relativity. Either way, revealing the source of cosmic acceleration can result in a paradigm shift in modern physics. Weak gravitational lensing is a subtle, coherent distortion of distant galaxy images due to gravitational potential, allowing the direct measurement of the spatial distribution of dark matter. Weak lensing is one of the most powerful cosmological probes because of its capability to measure the nature of cosmic acceleration through the evolution of the large-scale structure of the universe. Hyper Suprime-Cam (HSC), a newly developed prime focus camera at Subaru Telescope, started a wide, deep galaxy imaging survey in 2014, covering 1,100 sq. degrees of the sky down to the i-band limiting magnitude of 26. The wide field of view, light-gathering power, and superb image quality of HSC make it possible to measure weak lensing distortions with unprecedented precision. In this talk, I will present cosmology results from the Subaru Hyper Suprime-Cam Survey Year 3 data, mainly about cosmological constraints from cosmic shear and the combination of galaxy-galaxy lensing and clustering.
