2026ApJ..1000L..19Z

The James Webb Space Telescope (JWST) has recently identified A2744-QSO1 as a compact, metal-poor, black hole (BH)-dominated galaxy at z ≃ 7. This system exhibits an extreme black-hole-to-stellar mass ratio and unusually low metallicity, posing significant challenges to BH seeding models. Motivated by these discoveries, we perform high-resolution cosmological simulations with a massive primordial black hole (PBH; M_BH = 5 × 10⁷M_⊙) seed, incorporating for the first time a fully coupled treatment of PBH accretion, BH feedback, and Population III/II star formation and stellar feedback. Although PBHs accelerate structure formation through the seed effect, the associated strong thermal feedback from the accretion delays the onset of star formation to z ≲ 10, producing short, bursty episodes throughout the subsequent evolution. PBH-driven outflows expel enriched gas from the nucleus, while sustained inflows from the intergalactic medium continuously replenish pristine material. This feedback-regulated cycle naturally yields low accretion rates (${\dot{m}}_{\mathrm{BH}}/{\dot{m}}_{\mathrm{edd}}\sim 1 \% -10 \% $), subsolar metallicities (Z/Z_⊙ ≲ 10^–2), and extreme M_BH/M_⋆ ratios during both the initial star-forming phase and the subsequent quenching phases, in excellent agreement with JWST observations. Our results demonstrate that massive PBHs offer a viable pathway for forming the most extreme high-redshift systems, providing a physically motivated explanation for the extraordinary properties of A2744-QSO1, as a subclass of the broader population of JWST-discovered “little red dots.”