Colloquium on Mar. 28th, 2019

Strong Lensing and Substructures

Speaker: Dandan Xu (Tsinghua University)

Venue: Room 1113 (New SWIFAR building)

Time: 3:00 PM, Thursday, 28th March, 2019

Abstract: The LCDM cosmological model has established a predominant status for its widespread success in explaining cosmic structure formation and evolution. However, a number of discrepancies exist – to varying degrees – between the theory predictions and observations. These open up possibilities for alternative theories describing the fundamental properties of the Universe. Solutions to these open issues lie in our understanding of three main aspects, namely, the nature of dark matter, the state of dark energy and the (baryonic) physics of galaxy formation. In this regard, gravitational lensing, as predicted by Albert Einstein a century ago, has been shown to be a powerful astrophysical tool for their study. In this talk, I will review how gravitational lensing has been used to probe cosmic structure formation at all scales; in particular I will give three example applications in constraining the nature of dark matter (through strong lensing) and dark energy (through weak lensing), and the physics of galaxy formation (through a combination of lensing and stellar dynamics).