发表机构
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（东北大学; 名古屋市立大学; 日本国立天文台; 宫崎大学; 大阪大学; 芝浦工业大学; 国立工学期仙学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过XRISM和VLBI观测发现，高吸积率黑洞3C120的冷盘在约20引力半径处截断，内部由热流替代，喷流从该热内流区域发射，支持Blandford-Znajek机制，揭示盘-喷流联系的普适几何转变。
AI 中文摘要
相对论性喷流是宇宙中能量最高的现象之一，并通过能量反馈影响星系演化，然而吸积流与喷流发射之间的物理联系仍未得到解决。喷流产生被广泛归因于Blandford-Znajek机制，该机制通过由吸积流维持的大尺度磁场提取黑洞旋转能量。尽管这一机制在观测上得到了热、几何厚吸积流的支持，但具有强喷流的高吸积率环境却构成一个悖论，因为这类环境通常由冷、几何薄盘主导，而几何薄盘无法维持大尺度磁场。在此，我们报告了由X射线成像与光谱任务（XRISM）实现的协调X射线微量热计光谱观测，以及由全球毫米波VLBI阵列（GMVA）、甚长基线阵列（VLBA）和东亚VLBI网络（EAVN）进行的毫米/射电干涉观测，观测目标为宽线射电星系3C120。高分辨率X射线光谱揭示了一条相对论性展宽的Fe-Kα线，表明冷、几何薄盘在约20 R_g（R_g为引力半径）处被截断，内部区域被热、几何厚流取代。同时，射电成像表明，向黑洞视界外推的喷流轮廓所产生的半径与盘截断半径相当甚至更窄。这些结果表明，即使在高吸积率下，喷流发射也与热内流相关，可能通过Blandford-Znajek过程实现，为通过几何转变实现普适的盘-喷流联系提供了证据。
英文摘要
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 VLBI Array (GMVA), Very Long Baseline Array (VLBA), and East Asian VLBI Network (EAVN) on the broad-line radio galaxy 3C120. High-resolution X-ray spectroscopy reveals a relativistically-broadened Fe-K$α$ line, indicating that the cold, geometrically-thin disk is truncated at $\sim 20~R_{\rm g}$ ($R_{\rm g}$ 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.
Comments14 pages, 6 figures, 2 tables, Accepted for publication in the Astrophysical Journal Letters
