Tracing AGN-Galaxy Co-Evolution with UV Line-Selected Obscured AGN

Luigi Barchiesi; Lucia Marchetti; Mattia Vaccari; Cristian Vignali; Francesca Pozzi; Isabella Prandoni; Roberto Gilli; Marco Mignoli; Jose Afonso; Veeresh Singh; Catherine Hale; Ian Heywood; Matt Jarvis; Imogen Whittam

arXiv · 2511.19602

Tracing AGN-Galaxy Co-Evolution with UV Line-Selected Obscured AGN

Luigi Barchiesi·Lucia Marchetti·Mattia Vaccari·Cristian Vignali·Francesca Pozzi·Isabella Prandoni·Roberto Gilli·Marco Mignoli·Jose Afonso·Veeresh Singh·Catherine Hale·Ian Heywood·Matt Jarvis·Imogen Whittam

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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.

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Luigi Barchiesi, Lucia Marchetti, Mattia Vaccari, Cristian Vignali, Francesca Pozzi, Isabella Prandoni, Roberto Gilli, Marco Mignoli, Jose Afonso, Veeresh Singh, Catherine Hale, Ian Heywood, Matt Jarvis, Imogen Whittam. 2025-11-24. Tracing AGN-Galaxy Co-Evolution with UV Line-Selected Obscured AGN. https://arxiv.org/abs/2511.19602

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