JADES – the Rosetta stone of <i>JWST</i>-discovered AGN: deciphering the intriguing nature of early AGN

ABSTRACT JWST has discovered a large population of active galactic nuclei (AGN) at high redshift, which are weak in the X-rays. Here we present the NIRSpec spectrum of the most extreme of these objects, GN-28074, an AGN at $z=2.26$ with prominent hydrogen and He i broad lines, and with the highest limit on the bolometric to X-ray luminosity ratio among all spectroscopically confirmed AGN in GOODS. This source is also characterized by a mid-IR excess, likely associated with the AGN torus’ hot dust. The high bolometric luminosity and moderate redshift of this AGN allow us to explore its properties more in depth relative to other JWST-discovered AGN. The NIRSpec spectrum reveals prominent, slightly blueshifted absorption of H$\alpha$, H$\beta$, and He i $\lambda$10830. The Balmer absorption lines require gas with densities of $n_{\rm H}\gt 10^8~{\rm cm}^{-3}$, consistent with clouds in the broad-line region (BLR). This finding suggests that part of the X-ray weakness is due to high (Compton-thick) X-ray absorption by clouds in the BLR, or in its outer regions. GN-28074 is also extremely radio-weak. The radio weakness can also be explained in terms of absorption, as the inferred density of the BLR clouds makes them attenuate the radio emission through free–free absorption. Alternatively, the nuclear magnetic field may be underdeveloped, resulting both in intrinsically weak radio emission and lack of hot corona, hence intrinsic X-ray weakness. Finally, we show that recently proposed scenarios, invoking hyper-dense outflows or Raman scattering to explain the broad H$\alpha$, are ruled out.

Authors

Institutions

Publication Details

Journal
Monthly Notices of the Royal Astronomical Society
Published
2024-10-16
DOI
https://doi.org/10.1093/mnras/stae2367
Citations
57
Primary Topic
Gamma-ray bursts and supernovae
Type
article
Field-Weighted Citation Impact
18.90

Funders

Controls
|||
ALL TIME
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
article

JADES – the Rosetta stone of JWST-discovered AGN: deciphering the intriguing nature of early AGN

Francesco D’Eugenio, Joris Witstok, G. Risaliti, Santiago Arribas et al.
57 citations
Monthly Notices of the Royal Astronomical Society
Gamma-ray bursts and supernovae
18.90
article

JADES – the Rosetta stone of JWST-discovered AGN: deciphering the intriguing nature of early AGN

Francesco D’Eugenio, Joris Witstok, G. Risaliti, Santiago Arribas, Michele Perna, R. Maiolino, I. Prandoni, A. C. Fabian, Giovanni Mazzolari, Stefano Carniani, Kevin Hainline, Ignas Juodžbalis, Sandro Tacchella, Chris J. Willott, Pablo G. Pérez‐González, Xihan Ji, S. Charlot, Christina C. Williams, Hannah Übler, Jan Scholtz, Emma Curtis-Lake, R. Gilli, Andrew J. Bunker, Brant E. Robertson, Anna de Graaff, Eleonora Parlanti
article en
57 citations

Abstract

ABSTRACT JWST has discovered a large population of active galactic nuclei (AGN) at high redshift, which are weak in the X-rays. Here we present the NIRSpec spectrum of the most extreme of these objects, GN-28074, an AGN at $z=2.26$ with prominent hydrogen and He i broad lines, and with the highest limit on the bolometric to X-ray luminosity ratio among all spectroscopically confirmed AGN in GOODS. This source is also characterized by a mid-IR excess, likely associated with the AGN torus’ hot dust. The high bolometric luminosity and moderate redshift of this AGN allow us to explore its properties more in depth relative to other JWST-discovered AGN. The NIRSpec spectrum reveals prominent, slightly blueshifted absorption of H$\alpha$, H$\beta$, and He i $\lambda$10830. The Balmer absorption lines require gas with densities of $n_{\rm H}\gt 10^8~{\rm cm}^{-3}$, consistent with clouds in the broad-line region (BLR). This finding suggests that part of the X-ray weakness is due to high (Compton-thick) X-ray absorption by clouds in the BLR, or in its outer regions. GN-28074 is also extremely radio-weak. The radio weakness can also be explained in terms of absorption, as the inferred density of the BLR clouds makes them attenuate the radio emission through free–free absorption. Alternatively, the nuclear magnetic field may be underdeveloped, resulting both in intrinsically weak radio emission and lack of hot corona, hence intrinsic X-ray weakness. Finally, we show that recently proposed scenarios, invoking hyper-dense outflows or Raman scattering to explain the broad H$\alpha$, are ruled out.

Monthly Notices of the Royal Astronomical SocietyVol. 535(1)
Herzberg Institute of Astrophysics (CA), Centre National de la Recherche Scientifique (FR), University of Arizona (US), University of Hertfordshire (GB), Scuola Normale Superiore (IT), University of California, Santa Cruz (US), University of Cambridge (GB), Arcetri Astrophysical Observatory (IT), Institut d'Astrophysique de Paris (FR), Sorbonne Université (FR), University of Oxford (GB), Bridge University (SS), Max Planck Institute for Astronomy (DE), Istituto di Radioastronomia di Bologna (IT), Institute of Astronomy (RU), Centro de Astrobiología (ES), NSF NOIRLab (US), Osservatorio di Astrofisica e Scienza dello Spazio, University of Florence (IT), University College London (GB), University of Bologna (IT)
Kavli Foundation, UK Research and Innovation, Isaac Newton Trust, Science and Technology Facilities Council, H2020 European Research Council
Openalex Percentile: Top 0%
Gamma-ray bursts and supernovae
18.90
DOIOpen Access PDFOpenAlex
AI Navigator

Ask Laika to Summarize, Analyze, and Connect papers live on the map.

Summarize Papers & Methodologies

Extract key findings, datasets, and comparative methods across publications.

Benchmark Rankings & Visual Analytics

Rank top research institutions, authors, funders, topics, and journals by Field-Weighted Citation Impact (FWCI) and paper volume with instant charts.

Connect Distant Disciplines

Bridge topological clusters on the map to find hidden collaborative intersections.