Extreme properties of a compact and massive accreting black hole host in the first 500 Myr.

ABSTRACT: Little red dots (LRDs) are a high redshift galaxy population. Despite their high number densities, their nature is still uncertain. Here we present CANUCS-LRD-z8.6, a spectroscopically confirmed little red dot at a spectroscopic redshift of z_spec = 8.6319, hosting an active galactic nucleus. Its spectrum exhibits broad Hβλ4863 Å emission, high-ionization lines (C iv, N iv]), high electron temperature, which are indicative of active galactic nucleus activity, and low metallicity (Z < 0.1-0.2Z_⊙). The inferred black hole mass, MBH=1.0-0.4+0.6×108M⊙ , poses strong constraints on current black hole formation models and simulations. Additionally, its black hole is over-massive relative to its host, deviating from local M_BH - M_* relations, suggesting an

SUBMITTER: Tripodi R 

PROVIDER: S-EPMC12630725 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature