You can’t see me: Super-Eddington growth hindering X-ray detection in high-z broad-line active galactic nuclei

We revisit black hole mass estimates for high-redshift broad-line active galactic nuclei (AGNs) discovered with JWST by jointly analysing their broad emission lines and their systematic non-detections in deep Chandra imaging. Building upon a self-shadowed, super-Eddington accretion framework in which the corona undergoes efficient radiative over-cooling, we couple funnel-dependent Comptonisation physics with slim-disc spectral models and explore the resulting parameter space through a full Markov Chain Monte Carlo inference. Using a recently compiled sample of JWST high-redshift broad-line AGNs, we show that the observed X-ray weakness – manifested as extreme bolometric corrections, suppressed 2−10 keV luminosities, and non-detections in the 0.5−5 keV Chandra band – naturally arises when the corona is confined and radiatively over-cooled inside a narrow super-Eddington funnel. The combined broad line+X-ray analysis yields strongly bimodal posteriors: either very massive, very low-Eddington black holes (physically disfavoured), or a population of low-mass (∼10 6 − 10 7 M ⊙ ) black holes accreting at f Edd ≫ 1. The latter solution is strongly preferred for nearly all objects and returns masses consistent with, or lower than, local M BH − M ★ relations, mitigating the extreme mass ratios implied by single-epoch virial estimators. The predicted intrinsic spectra are redder and exhibit reduced hard-X-ray output but higher bolometric luminosities, implying bolometric corrections larger than those typical of the local AGN population, yet consistent with low-redshift highly accreting counterparts. These results support a picture in which many JWST broad-line AGNs are powered by rapidly growing, super-Eddington black holes whose suppressed coronal emission and self-shadowed broad-line region geometry combine to mimic overmassive black holes at z ≳ 6.