JADES: nitrogen enhancement in high-redshift broad-line active galactic nuclei
ABSTRACT The unexpectedly high nitrogen-to-oxygen (N/O) ratios observed in high-redshift (z) galaxies have challenged our understanding of early star formation. Notably, many of these nitrogen-rich galaxies show signatures of active galactic nuclei (AGNs), suggesting a possible connection between black hole formation and nitrogen enrichment. To explore this connection, we analyse stacked spectra of $z=4{\!-\!}7$ broad-line and narrow-line AGNs using deep Near Infrared Spectrograph data from the JWST Advanced Deep Extragalactic Survey. We identify a significant N iii] quintuplet and a high electron density (${\sim} 10^{4}$ cm$^{-3}$) only in the broad-line AGN stack, indicating nitrogen-rich ($\log (\mathrm{N/C})\simeq 0.5$, $\log (\mathrm{N/O})>-0.6$) and dense gas similar to the high-z nitrogen-rich galaxies. Our findings suggest that dense nuclear star formation may trap nitrogen-rich gas in proto-globular clusters, in line with the high N/O observed in local globular clusters; associated runaway stellar collisions could produce intermediate-mass black hole seeds, as predicted by some models and simulations, whose accretion results into AGN signatures. These findings support scenarios connecting the early black hole seeding and growth to merging processes within and between proto-globular clusters in primeval galaxies.
Authors
- Nimisha Kumari (ORCID: https://orcid.org/0000-0002-5320-2568)
- Francesco D’Eugenio (ORCID: https://orcid.org/0000-0003-2388-8172)
- Joris Witstok (ORCID: https://orcid.org/0000-0002-7595-121X)
- Zhiyuan Ji (ORCID: https://orcid.org/0000-0001-7673-2257)
- A. Feltre (ORCID: https://orcid.org/0000-0001-6865-2871)
- R. Maiolino (ORCID: https://orcid.org/0000-0002-4985-3819)
- Stefano Carniani (ORCID: https://orcid.org/0000-0002-6719-380X)
- Ignas Juodžbalis (ORCID: https://orcid.org/0009-0003-7423-8660)
- Jan Scholtz
- Chris J. Willott (ORCID: https://orcid.org/0000-0002-4201-7367)
- Xihan Ji (ORCID: https://orcid.org/0000-0002-1660-9502)
- S. Charlot (ORCID: https://orcid.org/0000-0003-3458-2275)
- Mirko Curti (ORCID: https://orcid.org/0000-0002-2678-2560)
- Pierluigi Rinaldi (ORCID: https://orcid.org/0000-0002-5104-8245)
- Hannah Übler (ORCID: https://orcid.org/0000-0003-4891-0794)
- Emma Curtis-Lake (ORCID: https://orcid.org/0000-0002-9551-0534)
- Andrew J. Bunker (ORCID: https://orcid.org/0000-0002-8651-9879)
- Brant E. Robertson (ORCID: https://orcid.org/0000-0002-4271-0364)
- Yuki Isobe (ORCID: https://orcid.org/0000-0001-7730-8634)
Institutions
- Herzberg Institute of Astrophysics (CA)
- University of Copenhagen (DK)
- Centre National de la Recherche Scientifique (FR)
- Space Telescope Science Institute (US)
- European Southern Observatory (DE)
- University of Arizona (US)
- University of Hertfordshire (GB)
- Waseda University (JP)
- 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)
- Max Planck Institute for Extraterrestrial Physics (DE)
- DAWN Center for Independent Living (US)
- University College London (GB)
Publication Details
- Journal
- Monthly Notices of the Royal Astronomical Society Letters
- Published
- 2025-05-15
- DOI
- https://doi.org/10.1093/mnrasl/slaf056
- Citations
- 14
- Primary Topic
- Astrophysics and Star Formation Studies
- Type
- article
- Field-Weighted Citation Impact
- 16.17
Funders
- National Science Foundation
- National Aeronautics and Space Administration
- University of California, Santa Cruz
- Space Telescope Science Institute
- UK Research and Innovation
- European Commission
- National Research Foundation
- Danmarks Grundforskningsfond
- Science and Technology Facilities Council
- Japan Society for the Promotion of Science