Super-Eddington Accretion of Black Holes in Early Nuclear Bursts Gives Birth to Little Red Dots

Abstract In a recent paper, Chen et al. developed a framework for modeling the seeding and growth of supermassive black holes (BHs) in the context of ΛCDM cosmogony. Here, we use a set of physically motivated criteria to select a population of predicted BHs and link them to little red dots (LRDs) discovered by JWST. We show that the LRD population at high redshift ( z ) emerges naturally from a subset of BHs with super-Eddington accretion during nuclear bursts. The model suggests that the observed LRDs are the “tip of the iceberg” of a much larger population of less luminous BHs in the same subset. The model makes specific predictions for the LRD population, such as the mass distributions of their BHs and host galaxies/halos, and the piece-wise redshift evolution of their number density. The cosmological context of the model also allows us to link the observed LRD population to their progenitors (their BH seeds) and lower- z descendant BHs, galaxies, and halos. Most LRDs at z ∼ 5 are seeded at z ≳ 20 through direct-collapse BHs or pair-instability supernovae from Pop-III stars and have grown to M BH ≈ 10 5 –10 7 M ⊙ through nuclear bursts by their observed redshift. LRDs are predicted to have diverse descendants, ranging from compact dwarf galaxies to brightest cluster galaxies (BCGs) at z = 0. These predictions are consistent with current observations and can be further tested. The success of this model indicates that the results presented here provide a robust foundation for building detailed models of the LRD population.