Rapidly growing primordial black holes as seeds of the massive high-redshift JWST Galaxies

Abstract

A group of massive galaxies at redshifts of z ≳ 7 have been recently detected by the James Webb Space Telescope (JWST), which were unexpected to form at such an early time within the standard Big Bang cosmology. In this work, we propose that this puzzle can be explained by the presence of some primordial black holes (PBHs) with a mass of ∼ 1000M_⊙. These PBHs act as seeds for early galaxy formation with masses of ∼ 10⁸–10¹⁰M_⊙ at high redshift, hence accounting for the JWST observations. We use a hierarchical Bayesian inference framework to constrain the PBH mass distribution models, and find that the Lognormal model with the M_c ∼ 750M_⊙ is preferred over other hypotheses. These rapidly growing BHs are expected to have strong radiation and may appear as high-redshift compact objects, similar to those recently discovered by JWST. Although we focused on PBHs in this work, the bound on the initial mass of the seed black holes remains robust even if they were formed through astrophysical channels.