SKA - VLBI view of AGN jets in the early Universe
C. Spingola, M. Mezcua, Y. Liu, S. Frey, S. Belladitta, T. An, M. Giroletti, A. Caccianiga, A. Moretti, L. Ighina, T. Sbarrato, G. Migliori, D. Dallacasa, L. I. Gurvits, K. É. Gabányi, K. Perger, Z. Paragi, R. D. Baldi, E. Bañados, G. Bernardi, M. Bondi, E. De Rubeis, F. D'Ammando, F. De Gasperin, I. Delvecchio, F. Vito, K. Rubinur, M. Krezinger, R. Lico, E. Momjian, M. Orienti, J. Hodgson, C. Stanghellini, A. Wang, M. Latif, H. Cao
astro-ph.GA, astro-ph.HE
Submitted: 2026-06-26
Comments: Published in Advancing Astrophysics with the SKA II (AASKAII), 2026 (arXiv:2606.20366). Report-no:AASKAII/Spingola01. Advancing Astrophysics with the SKA II (AASKAII) outlines the transformative scientific advances that will be enabled by the SKA telescopes
License: http://creativecommons.org/licenses/by-nc-sa/4.0/
The gist: Active Galactic Nuclei (AGN) are among the brightest sources in the Universe, and those that are also jetted are uniquely valuable at the earliest epochs, because their relativistic outflows can
Terminology
Abstract
Active Galactic Nuclei (AGN) are among the brightest sources in the Universe, and those that are also jetted are uniquely valuable at the earliest epochs, because their relativistic outflows can regulate the gas supply of their host galaxies, potentially affecting both early star formation and the rapid growth of supermassive black holes (SMBHs). Their compact, high-brightness-temperature radio cores provide the sharpest beacons for very long baseline interferometry (VLBI), enabling direct constraints on Doppler boosting, jet duty cycles, and jet - environment coupling at extreme redshifts. In this White Paper, we discuss how the SKA-VLBI will provide sub- mu Jy sensitivity together with milliarcsecond (mas) angular resolution to image and characterise jetted AGN at z>6 across SKA-Mid and SKA-Low frequencies. These observations can directly test SMBHs (>10 6 M) formation/evolution models (including jet-assisted super-Eddington phases) and infer the geometry of the Universe, directly probing the cosmological framework at high precision. Synergies with current and next-generation multi-band facilities will also be crucial to fully understand their host galaxies and their environment, providing an unprecedented panchromatic knowledge of the first jetted AGN.
Sources
- Time-domain Radio-loudness of Active Galactic Nuclei: Intermittency, Memory, and Jet Escape
- Euclid. I. Overview of the Euclid mission
- Revisiting the angular size-redshift cosmological test with milliarcsecond radio structures in active galactic nuclei
- The ``angular size - redshift'' relation for compact radio structures in quasars and radio galaxies
- Star cluster ecology III: Runaway collisions in young compact star clusters
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