JADES: A large population of obscured, narrow-line active galactic nuclei at high redshift

We present the identification of 41 narrow-line active galactic nuclei (type-2 AGN) candidates in the two deepest observations of the JADES spectroscopic survey with JWST/NIRSpec. The spectral coverage and the depth of our observations allowed us to select narrow-line AGN based on both rest-frame optical and UV emission lines up to z = 10. Due to the metallicity decrease of galaxies, at z > 3, the standard optical diagnostic diagrams (N2-BPT or S2-VO87) become unable to distinguish many AGN from other sources of photoionisation. Therefore, we also used high ionisation lines, such as He II λ 4686, He II λ 1640, [Ne IV ] λ 2422, [Ne V ] λ 3420, and N V λ 1240, also in combination with other UV transitions, to trace the presence of AGN. Out of a parent sample of 209 galaxies, we identified 42 type-2 AGN (although ten of them are tentative), making the fraction of galaxies in JADES hosting type-2 AGN about 20 ± 5%, which does not evolve significantly in the redshift range between 2 and 10. The selected type-2 AGN have estimated bolometric luminosities of 10 41.3 − 44.9 erg s −1 and host-galaxy stellar masses of 10 7.2 − 9.3 M ⊙ . The star formation rates of the selected AGN host galaxies are consistent with those of the star-forming main sequence. The AGN host galaxies at z = 4 − 6 contribute ∼18–30% to the UV luminosity function across different UV luminosity bins, increasing slightly with UV luminosity.

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Publication Details

Journal
Astronomy and Astrophysics
Published
2025-03-26
DOI
https://doi.org/10.1051/0004-6361/202348804
Citations
67
Primary Topic
Galaxies: Formation, Evolution, Phenomena
Type
article
Field-Weighted Citation Impact
77.37

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article

JADES: A large population of obscured, narrow-line active galactic nuclei at high redshift

Nimisha Kumari, Francesco D’Eugenio, Joris Witstok, Zhiyuan Ji et al.
67 citations
Astronomy and Astrophysics
Galaxies: Formation, Evolution, Phenomena
77.37
article

JADES: A large population of obscured, narrow-line active galactic nuclei at high redshift

Nimisha Kumari, Francesco D’Eugenio, Joris Witstok, Zhiyuan Ji, Santiago Arribas, Michele Perna, Fengwu Sun, R. Maiolino, Benjamin D. Johnson, Chiara Circosta, Stefano Carniani, Kevin Hainline, Jacopo Chevallard, Sandro Tacchella, Chris J. Willott, Rachana Bhatawdekar, Xihan Ji, S. Charlot, Mirko Curti, Jianwei Lyu, Christina C. Williams, Jan Scholtz, Tobias J. Looser, Daniel J. Eisenstein, Hannah Übler, Maddie S. Silcock, Emma Curtis-Lake, Christopher N. A. Willmer, William Baker, Kristan Boyett, Andrew J. Bunker, Brant E. Robertson, Marcia Rieke, Michael V. Maseda, Ryan Hausen, Giacomo Venturi, Eleonora Parlanti, Bruno Rodriguez Del
article en
67 citations

Abstract

We present the identification of 41 narrow-line active galactic nuclei (type-2 AGN) candidates in the two deepest observations of the JADES spectroscopic survey with JWST/NIRSpec. The spectral coverage and the depth of our observations allowed us to select narrow-line AGN based on both rest-frame optical and UV emission lines up to z = 10. Due to the metallicity decrease of galaxies, at z > 3, the standard optical diagnostic diagrams (N2-BPT or S2-VO87) become unable to distinguish many AGN from other sources of photoionisation. Therefore, we also used high ionisation lines, such as He II λ 4686, He II λ 1640, [Ne IV ] λ 2422, [Ne V ] λ 3420, and N V λ 1240, also in combination with other UV transitions, to trace the presence of AGN. Out of a parent sample of 209 galaxies, we identified 42 type-2 AGN (although ten of them are tentative), making the fraction of galaxies in JADES hosting type-2 AGN about 20 ± 5%, which does not evolve significantly in the redshift range between 2 and 10. The selected type-2 AGN have estimated bolometric luminosities of 10 41.3 − 44.9 erg s −1 and host-galaxy stellar masses of 10 7.2 − 9.3 M ⊙ . The star formation rates of the selected AGN host galaxies are consistent with those of the star-forming main sequence. The AGN host galaxies at z = 4 − 6 contribute ∼18–30% to the UV luminosity function across different UV luminosity bins, increasing slightly with UV luminosity.

Astronomy and AstrophysicsVol. 697
National Science Foundation, National Aeronautics and Space Administration, American Society for Radiation Oncology, University of California, Santa Cruz, Johns Hopkins University, Dell EMC, UK Research and Innovation, European Commission, Isaac Newton Trust, Ministerio de Ciencia e Innovación, Engineering and Physical Sciences Research Council, Science and Technology Facilities Council, European Research Council, Agencia Estatal de Investigación
Openalex Percentile: Top 0%
Galaxies: Formation, Evolution, Phenomena
77.37
DOIOpen Access PDFOpenAlex
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