Dark Bondi Accretion Aided by Baryons and the Origin of JWST Little Red Dots

Abstract

The gravothermal core collapse of self-interacting dark matter halos provides a mechanism for seeding supermassive black holes in the early Universe. We show that the collapse of a small fraction of the halo mass can trigger general-relativistic instability and produce black hole seeds in halos with masses $\gtrsim 10^9{\mathrm{M}}_{\odot }$ at high redshift. We investigate whether this process can account for the origin of JWST little red dots at $z\sim 4-11$, which host black holes with masses $\sim 10^7{\mathrm{M}}_{\odot }$. We find that such masses can be reached within $\sim 500\mathrm{Myr}$ through rapid core collapse followed by efficient accretion, even for initial seed masses of $1-10^3{\mathrm{M}}_{\odot }$. This scenario allows a substantial fraction of the black hole mass to originate from dark matter accretion, potentially offering a viable pathway to forming massive black holes at high redshift.

Comments: 6 pages, 2 figures, plus supplemental material (2 figures). Additional simulations demonstrated that core collapse is robust to baryonic feedback; the abundance of LRDs estimated; model caveats discussed