Topic: Self-interacting dark matter, collapsed halos, and high-redshift supermassive black holes

Speaker: Assist. Prof. Yi-Ming Zhong

Coordinates: PCFT C1124, 16:00, Thursday, May 9

Abstract: Over the past decades, we have accumulated compelling evidence for the existence of dark matter, yet its nature remains elusive. Dark matter could be part of the dark sectors, comprising hidden particles with new interactions. These new particles and interactions can alter the formation and evolution of various small-scale structures in the Universe. This talk will focus on the impacts of dark matter self-interactions, a common feature within the dark sector paradigm, on the properties of dark matter halos. Self-interacting dark matter halos experience gravothermal evolution, where the central halo initially forms a core that ultimately collapses. The core-collapsed phase diversifies the density distributions of dark matter halos. It also showcases the universality in the evolution of self-interacting dark matter halos as thermal systems. Current and future astrophysical observations could probe the properties of the collapsed dark matter halos through gravitational lensing and shed light on dark matter self-interactions. Furthermore, the collapsed halos may give birth to the supermassive black holes observed at high redshifts, a longstanding puzzle in astrophysics.