Modern imaging surveys such as Euclid, Vera Rubin’s LSST, and CSST will revolutionize our understanding of the Universe's bright and dark sides with deep imaging data and unprecedented weak gravitational lensing capabilities. Over the last two decades, this combination has demonstrated enormous potential in helping us understand the physical connection between galaxies and their dark matter halos. For example, I will introduce my research, which utilizes data from the Subaru Telescope’s primary focus camera, HSC, to understand the assembly of the most massive galaxies in the Universe. We illustrate the intriguing connection between the extended, low-surface-brightness stellar halo of low-redshift massive galaxies and the properties of their dark matter halos, and discuss its implications in cosmology.
