近日，中科院上海天文台的路如森研究员与合作者取得了一项新进展，他们发现了连接黑洞和喷流的M87中的环状吸积结构。相关成果已于2023年4月26日在国际权威学术期刊《自然》上发表。

该研究报道了2018年以3.5毫米波长获得的M87图像，首次展现出紧凑的射电核的空间分辨。高分辨率成像揭示了一个由8.4^+0.5_-1.1个Schwarzschild半径构成的环状结构，直径比在1.3毫米时观测到的环结构大50%以上，且在3.5毫米处的外沿也更加宽广。这一更大、更厚的环状结构表明吸积流的吸收效应对辐射的贡献十分重要，而不仅仅是引力透镜效应的环状辐射。图像还显示出边缘明亮的喷流与黑洞的吸积流相连，而在黑洞附近，喷流发射区的辐射剖面比预期的黑洞驱动喷流的剖面更加宽广，这表明吸积流周围可能存在与之相关的风。

据了解，近邻射电星系M87是研究黑洞吸积和喷流形成的主要研究对象。2017年，事件视界望远镜以1.3毫米波长观测到M87，并检测到一个环状结构，被解释为中心黑洞周围的引力透镜辐射。

附：英文原文

Title: A ring-like accretion structure in M87 connecting its black hole and jet

Author: Lu, Ru-Sen, Asada, Keiichi, Krichbaum, Thomas P., Park, Jongho, Tazaki, Fumie, Pu, Hung-Yi, Nakamura, Masanori, Lobanov, Andrei, Hada, Kazuhiro, Akiyama, Kazunori, Kim, Jae-Young, Marti-Vidal, Ivan, Gmez, Jos L., Kawashima, Tomohisa, Yuan, Feng, Ros, Eduardo, Alef, Walter, Britzen, Silke, Bremer, Michael, Broderick, Avery E., Doi, Akihiro, Giovannini, Gabriele, Giroletti, Marcello, Ho, Paul T. P., Honma, Mareki, Hughes, David H., Inoue, Makoto, Jiang, Wu, Kino, Motoki, Koyama, Shoko, Lindqvist, Michael, Liu, Jun, Marscher, Alan P., Matsushita, Satoki, Nagai, Hiroshi, Rottmann, Helge, Savolainen, Tuomas, Schuster, Karl-Friedrich, Shen, Zhi-Qiang, de Vicente, Pablo, Walker, R. Craig, Yang, Hai, Zensus, J. Anton, Algaba, Juan Carlos, Allardi, Alexander, Bach, Uwe, Berthold, Ryan, Bintley, Dan, Byun, Do-Young, Casadio, Carolina, Chang, Shu-Hao, Chang, Chih-Cheng, Chang, Song-Chu, Chen, Chung-Chen, Chen, Ming-Tang, Chilson, Ryan, Chuter, Tim C., Conway, John, Crew, Geoffrey B., Dempsey, Jessica T.

Issue&Volume: 2023-04-26

Abstract: The nearby radio galaxy M87 is a prime target for studying black hole accretion and jet formation1,2. Event Horizon Telescope observations of M87 in 2017, at a wavelength of 1.3mm, revealed a ring-like structure, which was interpreted as gravitationally lensed emission around a central black hole3. Here we report images of M87 obtained in 2018, at a wavelength of 3.5mm, showing that the compact radio core is spatially resolved. High-resolution imaging shows a ring-like structure of 8.4+0.5-1.1

Schwarzschild radii in diameter, approximately 50% larger than that seen at 1.3mm. The outer edge at 3.5mm is also larger than that at 1.3mm. This larger and thicker ring indicates a substantial contribution from the accretion flow with absorption effects, in addition to the gravitationally lensed ring-like emission. The images show that the edge-brightened jet connects to the accretion flow of the black hole. Close to the black hole, the emission profile of the jet-launching region is wider than the expected profile of a black-hole-driven jet, suggesting the possible presence of a wind associated with the accretion flow.

DOI: 10.1038/s41586-023-05843-w

Source: https://www.nature.com/articles/s41586-023-05843-w