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

Understand

The James Webb Space Telescope (JWST) has unearthed black holes as massive as $10^{6.2-8.1}M_\odot$ at redshifts of $z \sim 8.5-10.6$ 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 {\it astrophysical} seeding mechanisms and Eddington accretion rates that can explain the observed objects.
• We then appeal to {\it 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 $z_{\rm seed}=25$ and continuous accretion, all of the black holes studied here can either be explained through super-Eddington accretion (at an Eddington fraction of $f_{\rm Edd}<= 2.1 $) onto low-mass ($100M_\odot$) seeds or Eddington-limited accretion onto high-mass ($10^5 M_\odot$) seeds.