The SKA-VLBI Perspective on Radio-Quiet AGN

Francesca Panessa; Tao An; James Petley; Ailing Wang; Ranieri Diego Baldi; Ehud Behar; Emmanuel Bempong-Manful; Gabriele Bruni; Ning Chang; Sina Chen; Lang Cui; Filippo D'Ammando; Marcello Giroletti; Magdalena Kunert-Bajraszewska; Sibasish Laha; Ari Laor; Ian McHardy; Eileen Meyer; Monica Orienti; Miguel Pérez-Torres; Isabella Prandoni; Claudio Ricci; David R. A. Williams-Baldwin; Zsolt Paragi

arXiv · 2606.30307

The SKA-VLBI Perspective on Radio-Quiet AGN

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Abstract

The accretion-ejection mechanism in Active Galactic Nuclei (AGN) remains a central open problem in astrophysics, tied to the role of AGN feedback in galaxy formation and evolution. Radio-quiet AGN dominate the observed AGN population. Lacking luminous jets, their radio emission traces a rich set of processes spanning the host galaxy kpc scales down to the vicinity of the supermassive black hole: star formation, AGN-driven winds and shocks, free-free emission from photo-ionized gas, low-power jets, and coronal activity close to the inner accretion disk. The Square Kilometre Array (SKA) will probe these processes across a wide frequency range with unprecedented sensitivity, wide-field survey capability, and, critically, high-resolution VLBI imaging. Flux, spectral, and polarization monitoring will constrain dynamics and environmental coupling, while mapping nuclear regions on sub-pc to kpc scales will disentangle compact cores from host emission, resolving the diversity of radio activity across accretion regimes and jet powers from the local Universe to the cosmic dawn. At the full AA4 deployment, the SKA-MID phased into global VLBI arrays will deliver sub-milliarcsecond imaging and $\mu$Jy sensitivity over 0.35--15\,GHz, enabling the first population-level census of radio-quiet AGN nuclei. Earlier AA$\ast$ operations will support pilot studies of the brightest nearby systems.

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Francesca Panessa, Tao An, James Petley, Ailing Wang, Ranieri Diego Baldi, Ehud Behar, Emmanuel Bempong-Manful, Gabriele Bruni, Ning Chang, Sina Chen, Lang Cui, Filippo D'Ammando, Marcello Giroletti, Magdalena Kunert-Bajraszewska, Sibasish Laha, Ari Laor, Ian McHardy, Eileen Meyer, Monica Orienti, Miguel Pérez-Torres, Isabella Prandoni, Claudio Ricci, David R. A. Williams-Baldwin, Zsolt Paragi. 2026-06-29. The SKA-VLBI Perspective on Radio-Quiet AGN. https://arxiv.org/abs/2606.30307

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