Disk Truncation Triggers Relativistic Jet Launching of a Highly Accreting Supermassive Black Hole
Year: 2026
Type: article
Abstract: Relativistic jets are among the most energetic phenomena in the Universe and influence galaxy evolution through energetic feedback, yet the physical connection between accretion flows and jet launching remains unresolved. Jet production is widely attributed to the Blandford–Znajek mechanism, which extracts black hole rotational energy via large-scale magnetic fields sustained by an accretion flow. Although this mechanism is observationally well supported for hot, geometrically thick accretion flows, highly accreting environments with strong jets present a paradox, as they are typically dominated by cold, geometrically thin disks incapable of sustaining large-scale magnetic fields. Here, we report coordinated X-ray microcalorimeter spectroscopy achieved by X-ray Imaging and Spectroscopy Mission (XRISM) and millimeter–radio interferometric observations by Global Millimeter Very Long Baseline Interferometry (VLBI) Array (GMVA), Very Long Baseline Array (VLBA), and East Asian VLBI Network (EAVN) of the broad-line radio galaxy 3C 120. High-resolution X-ray spectroscopy reveals a relativistically broadened Fe K α line, indicating that the cold, geometrically thin disk is truncated at ∼20 R g ( R g is the gravitational radius), with the inner region replaced by a hot, geometrically thick flow. Concurrently, radio imaging indicates that jet profile extrapolation toward the black hole horizon yields a radius comparable to or even narrower than the disk truncation radius. These results demonstrate that, even at high accretion rates, jet launching is linked to a hot inner flow, possibly via the Blandford–Znajek process, providing evidence for a universal disk–jet connection via geometric transition.
Institutions: Tohoku University, Nagoya City University, National Astronomical Observatory of Japan, University of Miyazaki, The University of Osaka, Shibaura Institute of Technology, National Institute of Technology, Ichinoseki College, Yonsei University, Korea Astronomy and Space Science Institute, Kyungpook National University, National Taiwan University, Hiroshima University, Kyoto University
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,400
Funders: National Science Foundation, National Aeronautics and Space Administration, National Geographic Society, Kagoshima University, Daiko Foundation, National Astronomical Research Institute of Thailand, Academia Sinica, Kyungpook National University, Korea Astronomy and Space Science Institute, National Research Foundation of Korea, National Astronomical Observatory of Japan, Nagoya City University, Smithsonian Astrophysical Observatory, Japan Society for the Promotion of Science
Awards: G1806242956, Time Variations of Radiation Spectrum and Polarization in Black Hole Accretion Flows Supported by Azimuthal Magnetic Fields, Elucidating the origin of heavy elements by a space-based gamma-ray detector using liquid argon, G3920734589, X線精密分光による活動銀河核の円盤風の理解, AGN X-ray Microcalorimeter Spectroscopy and Multi-wavelength Monitor Measuring Supermassive Black Hole Spin, Spin measurement of supermassive black holes and verification of rotational-energy extraction mechanism via magnetic field, 現代天文学の粋を集めた観測で迫るブラックホール周囲の高温プラズマ, Probing jet formation and diversity of supermassive black holes with next-generation international millimeter radio interferometry networks, G6834019471, Unveiling the Driving Mechanisms of AGN Jets through the Synergy of High-Resolution X-ray Spectroscopy and Millimeter-Wave Imaging, Collaborative Research: RI:Small: Use-Inspired RL for Many-Agent Contexts: Co-opetition, Partial Observability, and Dynamic Types
OpenAlex ID: W7214172106