Exploring a primordial solution for early black holes detected with the JWST

The James Webb Space Telescope (JWST) has unearthed black holes as massive as 10^6. 2-8. 1M_ at redshifts of z 8. 5-10. 6 with many systems showing unexpectedly high black hole to stellar mass ratios >=30%, posing a crucial challenge for theoretical models. Using analytic calculations, we explore the combination of astrophysical seeding mechanisms and Eddington accretion rates that can explain the observed objects. We then appeal to cosmological primordial black hole (PBH) seeds and show how these present an alternative path for "seeding" early structures and their baryonic contents. Assuming seeding (via astrophysical means) at a redshift of z ₒ₄₄₃=25 and continuous accretion, all of the black holes studied here can either be explained through super-Eddington accretion (at an Eddington fraction of f ₄₃₃<= 2. 1) onto low-mass (100M_) seeds or Eddington-limited accretion onto high-mass (10⁵ M_) seeds. The upper limit, where we assume a primordial origin for all of these black holes, yields a continuous primordial black hole mass function (between 10^-5. 25 and 10^3. 75 M_) and a fractional PBH value <= 10^-12, in good agreement with observational constraints. Starting at the redshift of matter-radiation equality (z 3400), we show how PBH-driven structure formation can reproduce the observed stellar and black hole masses for two of the highest redshift black holes (UHZ1 and GHZ9 at z 10. 3) with the same parameters governing star formation, black hole accretion and their feedbacks. Exploring a wide swathe of model parameter space for GHZ9, we find black hole-to-stellar mass ratios ranging between 0. 1-1. 86 i. e. in some cases (of high supernova feedback), the black hole grows to be more massive than its host halo, presenting an attractive alternative to seeding these puzzling early systems.