A new theoretical model proposes that the supermassive black holes (SMBHs) observed in early galaxies, known as "little red dots" (LRDs) by the James Webb Space Telescope (JWST), could have formed from runaway mergers of primordial black holes (PBHs) in clusters. This mechanism, involving long-short mode coupling on small scales in the early Universe, offers an explanation for the rapid emergence of massive SMBHs in early cosmic epochs, a phenomenon that has challenged standard cosmological theories.

This research derives the mass function of SMBHs resulting from this process, as well as the compactness and "overmassive" features of LRDs. Furthermore, the model estimates that the dense gas residing in these PBH clusters is consistent with current LRD observations. This hypothesis suggests that PBHs could have acted as "seeds" for SMBH formation much earlier than conventional growth mechanisms would allow.

SMBH formation from PBH clusters not only explains the properties of LRDs but could also accelerate galaxy formation at high redshifts. This is crucial as it helps alleviate the tension between JWST observations regarding the abundance of early galaxies and the predictions of the standard ΛCDM cosmological model. The presence of these early SMBHs could have influenced gas evolution and star formation in the early universe, facilitating the emergence of complex galactic structures.