Origin of Little Red Dots Explained by Ultra Self-Interacting Dark Matter

The James Webb Space Telescope has revealed hundreds of compact, dust-reddened active galactic nuclei — "Little Red Dots" (LRDs) — that are ubiquitous at z > 4, with estimated black hole masses exceeding 10^5 solar masses. The origin of these early-Universe supermassive black holes remains unexplained. We introduce a framework where a fraction of the self-interacting dark matter halo is ultra-self-interacting (uSIDM), with a large cross section that rapidly accelerates gravothermal collapse in halo centers. Our results show that the consequent seeded black hole experiences sub-Eddington accretion to reach the large observed LRD masses. This uSIDM seeding channel provides a viable mechanism for the origin and growth of LRDs, linking dark matter microphysics to early quasar formation.