@misc{10481/108147,
year = {2025},
month = {11},
url = {https://hdl.handle.net/10481/108147},
abstract = {We present a systematic search for broad-line active galactic nuclei (AGNs) in the ALPINE–CRISTAL–JWST sample of 18
star-forming galaxies (M > 109.5 M) at redshifts z = 4.4–5.7. Using James Webb Space Telescope (JWST)/NIRSpec IFU, we
identify seven AGN candidatesthrough the detection of broad H α emission linesfrom 33 aperture spectra centred on photometric
peaks. These candidates include one highly robust AGN detection with full width at half-maximum (FWHM) ∼2800 km s−1
and six showing broad components with FWHM ∼ 600–1600 km s−1, with two in a merger system. We highlight that only
broad-line detection is effective since these candidates uniformly lie within narrow emission-line ratio diagnostic diagrams where
star-forming galaxies and AGNs overlap. The broad-line AGN fraction ranges from 5.9 per cent to 33 per cent, depending on the
robustness of the candidates. Assuming that the majority are AGNs, the relatively high AGN fraction is likely due to targeting
high-mass galaxies, where simulations demonstrate that broad-line detection is more feasible. Their black hole masses range
from 106 to 107.5 M with 0.1  Lbol/LEdd  1. Counter to previous JWST studies at high redshift that found overmassive black
holes relative to their host galaxies, our candidates lie close to or below the local MBH–M scaling relations, thus demonstrating
the effect of selection biases. This study provides new insights into AGN–host galaxy co-evolution at high redshift by identifying
faint broad-line AGNs in galaxy samples, highlighting the importance of considering mass-dependent selection biases and the
likelihood of a large population of AGNs being undermassive and just now being tapped by JWST.},
organization = {China Scholarship Council (Nº 20230634000)},
organization = {ERC – European Research Council (ERC Advanced Grant 695671 ‘QUENCH’)},
organization = {ANID - FONDECYT (Nº 1252054; 1221846; 21221511)},
publisher = {Oxford University Press},
keywords = {Methods: data analysis},
keywords = {Galaxies: active},
keywords = {Galaxies: evolution},
title = {The ALPINE–CRISTAL–JWST survey: revealing less massive black holes in high-redshift galaxies},
doi = {10.1093/mnras/staf1709},
author = {The ALPINE-CRISTAL-JWST Collaboration and Relaño Pastor, Mónica},
}