# JADES. The diverse population of infant Black Holes at 4<z<11: merging, tiny, poor, but mighty

**Authors:** Roberto Maiolino, Jan Scholtz, Emma Curtis-Lake, Stefano Carniani, William Baker, Anna de Graaff, Sandro Tacchella, Hannah Übler, Francesco D'Eugenio, Joris Witstok, Mirko Curti, Santiago Arribas, Andrew J. Bunker, Stéphane Charlot, Jacopo Chevallard, Daniel J. Eisenstein, Eiichi Egami, Zhiyuan Ji, Gareth C. Jones, Jianwei Lyu  
**arXiv:** [2308.01230](https://arxiv.org/abs/2308.01230)  
**Date:** 2023-08-02  
**Summary page:** https://www.summarizepaper.com/en/paper/2308.01230v1/

## Key points

- 12 new active galactic nuclei (AGN) at redshifts between 4 and 7 identified in the JADES survey
- Previously known AGN in GN-z11 at a redshift of 10.6 also detected
- AGN detected through Broad Line Region observed in Balmer emission lines
- JADES survey depth and spectral resolutions allow exploration of lower mass regimes
- Some newly discovered AGN show evidence for two broad components of Halpha, suggesting candidate merging black holes
- Inferred masses of black holes range from 8 x 10^7 solar masses to 4 x 10^5 solar masses, probing Direct Collapse Black Hole regime
- Bolometric luminosities range from approximately 10^44 to 10^45 erg/s, indicating accretion rates generally less than half of Eddington rate
- Smaller black holes with masses around 10^6 solar masses tend to accrete at or above their Eddington rates
- Early black holes are over-massive relative to expected based on local M_BH-Mstar relation, but align more closely with local relations based on velocity dispersion or dynamical mass
- AGN located in region typically occupied by star-forming galaxies on BPT excitation-diagnostic diagram, implying they would be missed by standard classification techniques without broad line features in spectra
- Location of AGN on diagram consistent with what is expected for AGN hosted in metal-poor galaxies
- Fraction of broad line AGN with luminosities greater than 10^44 erg/s among galaxies in redshift range 4–6 is approximately 10%
- Suggests contribution from both AGNs and their host galaxies towards reionization process may be higher than previously thought - likely greater than 10%

## Summary

In the JADES survey, 12 new active galactic nuclei (AGN) at redshifts between 4 and 7 have been identified, in addition to the previously known AGN in GN-z11 at a redshift of 10.6. These AGN were detected through the presence of a Broad Line Region observed in the Balmer emission lines. The depth of the JADES survey, combined with three different spectral resolutions, allowed for exploration of lower mass regimes compared to previous studies. Some of these newly discovered AGN exhibit evidence for two broad components of Halpha, suggesting that they could be candidate merging black holes. The inferred masses of these black holes range from 8 x 10^7 solar masses down to 4 x 10^5 solar masses, which interestingly probes the regime expected for Direct Collapse Black Holes. The bolometric luminosities of these AGN range from approximately 10^44 to 10^45 erg/s, indicating accretion rates that are generally less than half of the Eddington rate. However, smaller black holes with masses around 10^6 solar masses tend to accrete at or above their Eddington rates. Comparing these early black holes to their host galaxies' stellar masses reveals that they are over-massive relative to what is expected based on the local M_BH-Mstar relation. However, when considering relations between black hole mass and velocity dispersion or dynamical mass, these early black holes align more closely with the local relations. This suggests that these relations may be more fundamental and universal. On the BPT excitation-diagnostic diagram which is commonly used to classify galaxies based on their ionization sources; these AGN are located in a region typically occupied by star-forming galaxies. This implies that without broad line features in their spectra they would be missed by standard classification techniques. The location of these AGN on this diagram is consistent with what is expected for AGN hosted in metal-poor galaxies. The fraction of broad line AGN with luminosities greater than 10^44 erg/s among galaxies in the redshift range 4–6 is approximately 10%. This suggests that contribution from both AGNs and their host galaxies towards reionization process may be higher than previously thought - likely greater than 10%.