Tracing AGN-Galaxy Co-Evolution with UV Line-Selected Obscured AGN
Abstract
Understanding black hole-galaxy co-evolution and the role of AGN feedback requires complete AGN samples, including heavily obscured systems. In this work, we present the first UV line-selected ([Nev]3426 and CIV1549) sample of obscured AGN with full X-ray-to-radio coverage, assembled by combining data from the Chandra COSMOS Legacy survey, the COSMOS2020 catalogue, IR photometry from XID+, and radio observations from the VLA and MIGHTEE surveys. Using CIGALE to perform spectral energy distribution (SED) fitting, we analyse 184 obscured AGN at 0.6 < z < 1.2 and 1.5 < z < 3.1, enabling detailed measurements of AGN and host galaxy properties, and direct comparison with SIMBA hydrodynamical simulations. We find that X-ray and radio data are essential for accurate SED fits, with the radio band proving critical when X-ray detections are missing or in cases of poor IR coverage. Comparisons with matched non-active galaxies and simulations suggest that the [NeV]-selected sources are in a pre-quenching stage, while the CIV-selected ones are likely quenched by AGN activity. Our results indicate that [NeV] and CIV selections target galaxies in a transient phase of their co-evolution, characterised by intense, obscured accretion, and pave the way for future extensions with upcoming large area high-z spectroscopic surveys.
Keywords
Cite
@article{arxiv.2511.19602,
title = {Tracing AGN-Galaxy Co-Evolution with UV Line-Selected Obscured AGN},
author = {Luigi Barchiesi and Lucia Marchetti and Mattia Vaccari and Cristian Vignali and Francesca Pozzi and Isabella Prandoni and Roberto Gilli and Marco Mignoli and Jose Afonso and Veeresh Singh and Catherine Hale and Ian Heywood and Matt Jarvis and Imogen Whittam},
journal= {arXiv preprint arXiv:2511.19602},
year = {2025}
}
Comments
Accepted for publication in MNRAS, 20 pages, 14 figures