A ring-like accretion structure in M87 connecting its black hole and jet
Authors: 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 , Gómez José 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. , Dornbusch Sven , Faber Aaron , Friberg Per , García Javier González , Garrido Miguel Gómez , Han Chih-Chiang , Han Kuo-Chang , Hasegawa Yutaka , Herrero-Illana Ruben , Huang Yau-De , Huang Chih-Wei L. , Impellizzeri Violette , Jiang Homin , Jinchi Hao , Jung Taehyun , Kallunki Juha , Kirves Petri , Kimura Kimihiro , Koay Jun Yi , Koch Patrick M. , Kramer Carsten , Kraus Alex , Kubo Derek , Kuo Cheng-Yu , Li Chao-Te , Lin Lupin Chun-Che , Liu Ching-Tang , Liu Kuan-Yu , Lo Wen-Ping , Lu Li-Ming , MacDonald Nicholas , Martin-Cocher Pierre , Messias Hugo , Meyer-Zhao Zheng , Minter Anthony , Nair Dhanya G. , Nishioka Hiroaki , Norton Timothy J. , Nystrom George , Ogawa Hideo , Oshiro Peter , Patel Nimesh A. , Pen Ue-Li , Pidopryhora Yurii , Pradel Nicolas , Raffin Philippe A. , Rao Ramprasad , Ruiz Ignacio , Sanchez Salvador , Shaw Paul , Snow William , Sridharan T. K. , Srinivasan Ranjani , Tercero Belén , Torne Pablo , Traianou Efthalia , Wagner Jan , Walther Craig , Wei Ta-Shun , Yang Jun , Yu Chen-Yu 
Published: April 2023

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 1.3 mm, 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 3.5 mm, showing that the compact radio core is spatially resolved. High-resolution imaging shows a ring-like structure of $${8.4}_{-1.1}^{+0.5}$$

8.4

−
1.1

+
0.5

Schwarzschild radii in diameter, approximately 50% larger than that seen at 1.3 mm. The outer edge at 3.5 mm is also larger than that at 1.3 mm. 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.