A Comprehensive JWST/NIRSpec Census of Broad-Line Active Galactic Nuclei: Faint, Tiny, but Highly Accreting Sources in the Remote Universe

Fuente: arXiv
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Main Authors: Baccus, Caroline, Xu, Xinfeng
Format: Preprint
Published: 2025
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author Baccus, Caroline
Xu, Xinfeng
author_facet Baccus, Caroline
Xu, Xinfeng
contents We present a sample of 252 broad-line Active Galactic Nuclei (BLAGNs), incorporating 171 newly identified sources, spanning a redshift interval from $z$ = 0.8 to 7.2. We have analyzed spectroscopic data from the NIRSpec instrument aboard the James Webb Space Telescope, using the G140H, G140M, G235H, G235M, G395H, and G395M gratings to survey N $\sim$ 80,000 galaxies for BLAGNs. Through emission-line fitting, using a sum of Gaussian models for {H$α$}, {H$β$}, [N II] $λ\lambda6548, 6584$, and [O III] $ λ\lambda4959, 5007$, we separate AGN broad-line components from narrow-line emission. We find the detection rate of BLAGNs to be relatively consistent across our redshift range. Compared to typical low-$z$ AGNs ($z$ $\lesssim$ 1), the high-$z$ BLAGNs are systematically fainter and less massive, yet they accrete more efficiently, with most showing Eddington ratios between 0.1 and 1.0. This confirms the rapid black hole growth during the early cosmic epochs. The detection of faint, low-mass BLAGNs at high redshift also helps bridge the observational gap between local supermassive black holes and remote luminous quasars, providing a more complete view of black hole-galaxy coevolution across cosmic time.
format Preprint
id arxiv_https___arxiv_org_abs_2512_03281
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A Comprehensive JWST/NIRSpec Census of Broad-Line Active Galactic Nuclei: Faint, Tiny, but Highly Accreting Sources in the Remote Universe
Baccus, Caroline
Xu, Xinfeng
Astrophysics of Galaxies
We present a sample of 252 broad-line Active Galactic Nuclei (BLAGNs), incorporating 171 newly identified sources, spanning a redshift interval from $z$ = 0.8 to 7.2. We have analyzed spectroscopic data from the NIRSpec instrument aboard the James Webb Space Telescope, using the G140H, G140M, G235H, G235M, G395H, and G395M gratings to survey N $\sim$ 80,000 galaxies for BLAGNs. Through emission-line fitting, using a sum of Gaussian models for {H$α$}, {H$β$}, [N II] $λ\lambda6548, 6584$, and [O III] $ λ\lambda4959, 5007$, we separate AGN broad-line components from narrow-line emission. We find the detection rate of BLAGNs to be relatively consistent across our redshift range. Compared to typical low-$z$ AGNs ($z$ $\lesssim$ 1), the high-$z$ BLAGNs are systematically fainter and less massive, yet they accrete more efficiently, with most showing Eddington ratios between 0.1 and 1.0. This confirms the rapid black hole growth during the early cosmic epochs. The detection of faint, low-mass BLAGNs at high redshift also helps bridge the observational gap between local supermassive black holes and remote luminous quasars, providing a more complete view of black hole-galaxy coevolution across cosmic time.
title A Comprehensive JWST/NIRSpec Census of Broad-Line Active Galactic Nuclei: Faint, Tiny, but Highly Accreting Sources in the Remote Universe
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2512.03281