Probing the Collisionless Nature of Dark Matter through Galaxy Cluster Studies

Sut-Ieng Tam^1*

¹Institute of Physics, National Yang Ming Chiao Tung University, Taiwan

* Presenter:Sut-Ieng Tam, email:sitam@nycu.edu.tw

Dark matter constitutes the majority of the matter content in our Universe, yet its fundamental properties remain uncertain. While the standard cosmological model, ΛCDM, successfully describes the large-scale structure of the Universe, several small-scale discrepancies have motivated the exploration of alternative dark matter models, such as self-interacting dark matter (SIDM). In this talk, I will review various observational probes used to constrain the self-interaction cross-section of dark matter, focusing on galaxy cluster-based measurements. I will then present our recent approach that leverages the radial acceleration relation (RAR) in galaxy clusters as a novel probe of SIDM. By comparing theoretical RAR predictions from cosmological hydrodynamical simulations under both Cold Dark Matter (CDM) and SIDM frameworks with observational data, we derive new constraints on the self-interaction cross-section. This analysis provides fresh insights into the fundamental nature of dark matter.

Keywords: dark matter, galaxy cluster, RAR