Cosmic Structures in CDM and SIDM

Abstract

The standard $\Lambda$ Cold Dark Matter ($\Lambda$CDM) model has achieved remarkable success in explaining the formation and evolution of cosmic structures on large scales, supported by a wide range of observations, including the cosmic microwave background, large-scale structure surveys, and galaxy clusters. However, discrepancies between theoretical predictions and observations on small scales, have motivated the exploration of alternative dark matter models, including the self-interacting dark matter (SIDM) scenario. This review provides an overview of the theoretical foundations of CDM structure formation, the small-scale challenges, and the solutions proposed within the SIDM framework. We summarize recent theoretical developments in the SIDM framework and discuss current observational constraints on the dark matter self-interaction cross-section with particular emphasis on galaxy clusters.

34 pages, 5 figures. Invited review for "One Hundred and Ten Years of General Relativity: Reviews and Perspectives". Accepted for publication in IJMPD