| Title: |
Too many or too massive? Investigating the high- z demography of active SMBHs from JWST |
| Authors: |
Roberts, Daniel; Shankar, Francesco; Cammelli, Vieri; Fontanot, Fabio; Trinca, Alessandro; Bisigello, Laura; Bonta, Elena Dalla; Fu, Hao; Gilli, Roberto; Grazian, Andrea; Graziani, Luca; Lapi, Andrea; Menci, Nicola; Scholtz, Jan; Varadarajan, Karthik Mahesh |
| Publisher Information: |
Oxford University Press (OUP) |
| Publication Year: |
2026 |
| Collection: |
University of Central Lancashire: CLOK - Central Lancashire Online Knowledge |
| Subject Terms: |
F500 - Astronomy |
| Description: |
Recent JWST observations have unveiled a numerous population of low-luminosity active galactic nuclei (AGN) at 4 ≲ z ≲ 10, with space densities roughly an order of magnitude above pre-JWST estimates, and many of these AGN have masses orders of magnitude above the local black hole mass–stellar mass (MBH − M⋆) scaling relations. We investigate the consistency of these observations within a data-driven framework that links the galaxy stellar mass function to the supermassive black hole (SMBH) mass function and AGN luminosity functions using different MBH − M⋆ relations and the observed Eddington-ratio distribution. By comparing our predictions against observed AGN luminosity functions at z ∼ 5.5 we find that observations can be reproduced either by highly-elevated MBH − M⋆ relations paired with low duty cycles (fAGN ∼ 0.08), or moderate relations with higher duty cycles (fAGN ∼ 0.5). Through the Sołtan argument, we find that MBH − M⋆ relations that are modestly above the local relation for AGN produce consistency between multiple tracers of the SMBH demography at z ∼ 5.5, while more extreme normalisations would require a weakly-evolving luminosity function at z ≥ 5.5. Continuity-equation modelling shows that initially high MBH − M⋆ relations predict a strong two-phase evolutionary scenario and very steep low-mass SMBH mass functions in tension with several current estimates, while more moderate relations generate local SMBH mass functions in better agreement with present determinations and near-constant scaling relations. Our results favour a scenario where SMBHs at z ∼ 5 on average lie modestly above local AGN scaling relations, with elevated but physically plausible duty cycles. Future wide-field clustering and demographic studies will help break the remaining degeneracies between SMBH scaling relations and AGN duty cycles at early cosmic times. |
| Document Type: |
article in journal/newspaper |
| File Description: |
application/pdf |
| Language: |
English |
| ISSN: |
0035-8711 |
| Relation: |
https://knowledge.lancashire.ac.uk/id/eprint/58279/1/58279%20Roberts%20et%20al.%20VOR.pdf; Roberts, Daniel orcid iconorcid:0009-0009-7662-0445 , Shankar, Francesco orcid iconorcid:0000-0001-8973-5051 , Cammelli, Vieri, Fontanot, Fabio orcid iconorcid:0000-0003-4744-0188 , Trinca, Alessandro orcid iconorcid:0000-0002-1899-4360 , Bisigello, Laura orcid iconorcid:0000-0003-0492-4924 , Bonta, Elena Dalla, Fu, Hao orcid iconorcid:0009-0002-8051-1056 , Gilli, Roberto et al (2026) Too many or too massive? Investigating the high- z demography of active SMBHs from JWST. Monthly Notices of the Royal Astronomical Society, 546 (4). ISSN 0035-8711 |
| DOI: |
10.1093/mnras%2Fstag223 |
| DOI: |
10.1093/mnras/stag223 |
| Availability: |
https://knowledge.lancashire.ac.uk/id/eprint/58279/; https://doi.org/10.1093/mnras%2Fstag223; https://doi.org/10.1093/mnras/stag223; https://knowledge.lancashire.ac.uk/id/eprint/58279/1/58279%20Roberts%20et%20al.%20VOR.pdf |
| Rights: |
cc_by_4 |
| Accession Number: |
edsbas.52377D5C |
| Database: |
BASE |