Abstract
Gravitational lensing describes the bending of light due to spacetime curvature owing to massive objects in the universe, manifesting as apparent positional shifts and magnifications of background objects. Among the different lensing regimes, I focus on studying lensed transients – individual luminous stars being temporarily magnified by foreground stars – found in galaxy clusters. Over the last decade, a multitude of such lensed transient events were detected by the Hubble Space Telescope and its successor, the James-Webb Space Telescope. In this seminar, I will demonstrate how we make use of the detection rate and spatial distribution of these transients as a pioneer probe of two of the arguably most important questions in astronomy as well as fundamental physics: 1) star formation physics, in particular, the initial mass function (IMF) in higher redshift galaxies; 2) The nature of Dark Matter, whether comprising weakly interactive massive particles (ϱCDM) or ultra-light axions (ψCDM).
Anyone interested is welcome to attend.