Probing Dark Matter Self-Interactions with Evolving Properties of Dark Matter Halos

Description

Despite compelling evidence supporting the existence of dark matter, the nature of dark matter remains elusive. Dark matter could be part of “dark sectors”, composing hidden particles with new interactions. These new particles could mediate self-interactions within dark matter, leading to the so-called “gravothermal evolution” of dark matter halos after their formation. Investigating the evolving properties of halos through astrophysical observations could offer a pathway to understanding dark matter self-interactions and, by extension, the nature of dark matter. Achieving this goal demands a reliable, efficient, and flexible simulator for self-interacting dark matter halos. Our previous work laid the foundation by developing a semi-analytical fluid model. This model can efficiently simulate various self-interacting dark matter models with few computational resources. It can also be conveniently calibrated against N-body simulations. The proposed project aims to develop our semi-analytical model further to incorporate important cosmological environmental effects that can significantly impact halo properties. With the expanded halo simulator, we will deduce observational signatures of dark matter self-interactions through stellar kinematics and weak lensing measurements. Our previous expertise, which includes constraining self-interacting dark matter through stellar kinematics of dwarf galaxies and strong lensing systems from the Hubble Space Telescope, will guide this effort. A focus will be placed on harnessing the potential of upcoming data from new galaxy survey telescopes, such as the Rubin Observatory, the Euclid Telescope, and the Chinese Space Survey Telescope. By synthesizing various observational probes and information from terrestrial dark matter experiments, we aim to answer if dark matter self-interacts. Furthermore, this project could set a common theme that connects researchers in the astronomy and particle physics communities in Hong Kong and beyond, potentially transforming Hong Kong into a global hub for astronomical research.