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

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Autori principali: Trinca, Alessandro, Lupi, Alessandro, Haardt, Francesco, Madau, Piero
Natura: Preprint
Pubblicazione: 2026
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author Trinca, Alessandro
Lupi, Alessandro
Haardt, Francesco
Madau, Piero
author_facet Trinca, Alessandro
Lupi, Alessandro
Haardt, Francesco
Madau, Piero
contents 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 MCMC 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 ($\sim 10^{6}$-$10^{7} M_{\odot}$) black holes accreting at $f_{\rm Edd} \gg 1$. The latter solution is strongly preferred for nearly all objects and returns masses consistent with, or lower than, local $M_{\rm BH}$-$M_{\star}$ 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 BLR geometry combine to mimic overmassive black holes at $z \gtrsim 6$.
format Preprint
id arxiv_https___arxiv_org_abs_2602_22305
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle You can't see me: Super-Eddington growth hindering X-ray detection in high-z broad-line active galactic nuclei
Trinca, Alessandro
Lupi, Alessandro
Haardt, Francesco
Madau, Piero
Astrophysics of Galaxies
High Energy Astrophysical Phenomena
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 MCMC 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 ($\sim 10^{6}$-$10^{7} M_{\odot}$) black holes accreting at $f_{\rm Edd} \gg 1$. The latter solution is strongly preferred for nearly all objects and returns masses consistent with, or lower than, local $M_{\rm BH}$-$M_{\star}$ 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 BLR geometry combine to mimic overmassive black holes at $z \gtrsim 6$.
title You can't see me: Super-Eddington growth hindering X-ray detection in high-z broad-line active galactic nuclei
topic Astrophysics of Galaxies
High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2602.22305