Researchers using the Event Horizon Telescope have significantly advanced our understanding of the supermassive black hole at the center of M87, revealing new details about its rotation and the turbulent gas surrounding it.
By comparing observations from 2017 and 2018, they have confirmed predictions and deepened insights into the dynamic environment of black holes, paving the way for future discoveries with ongoing analysis of more recent data.
Black Hole Dynamics
Using observations from 2017 and 2018, the Event Horizon Telescope (EHT) Collaboration has provided new insights into the supermassive black hole at the center of the galaxy Messier 87, known as M87*. This study takes black hole research a step further by analyzing data over multiple years and utilizing a greatly expanded image simulation library, which now includes over 120,000 additional images.
The research confirms that M87*’s rotational axis is pointed away from Earth and highlights the role of turbulence in the black hole’s accretion disk — the swirling gas surrounding it. This turbulence is key to understanding why the brightest part of the black hole’s ring appeared to shift between 2017 and 2018. These findings, published in Astronomy & Astrophysics, represent a significant advancement in our understanding of black hole behavior and dynamics.
Six years after releasing the first-ever image of a black hole, the EHT team continues to refine their analysis of M87*, offering fresh perspectives on the plasma surrounding the event horizon. By combining observations from different years, researchers are uncovering new details about the complex environment near black holes, shedding light on their ever-evolving nature.
Advances in Theoretical Understanding
This research represents a significant leap forward in our understanding of the extreme processes governing black holes and their environments, providing fresh theoretical insights into some of the universe’s most mysterious phenomena.
“The black hole accretion environment is turbulent and dynamic. Since we can treat the 2017 and 2018 observations as independent measurements, we can constrain the black hole’s surroundings with a new perspective,” says Hung-Yi Pu, assistant professor at National Taiwan Normal University. “This work highlights the transformative potential of observing the black hole environment evolving in time.”
Validation of Predictions and Future Outlook
The 2018 observations confirm the presence of the luminous ring first captured in 2017, with a diameter of approximately 43 microarcseconds—consistent with theoretical predictions for the shadow of a 6.5-billion-solar-mass black hole. Notably, the brightest region of the ring has shifted 30 degrees counter-clockwise.
“The shift in the brightest region is a natural consequence of turbulence in the accretion disk around the black hole,” explains Abhishek Joshi, PhD candidate at the University of Illinois Urbana-Champaign. “In our original theoretical interpretation of the 2017 observations, we predicted that the brightest region would most likely shift in the counterclockwise direction. We are very happy to see that the observations in 2018 confirmed this prediction!”
Deepening Understanding with Enhanced Data
The fact that the ring remains brightest on the bottom tells us a lot about the orientation of the black hole spin. Bidisha Bandyopadhyay, a Postdoctoral Fellow from Universidad de Concepción adds: “The location of the brightest region in 2018 also reinforces our previous interpretation of the black hole’s orientation from the 2017 observations: the black hole’s rotational axis is pointing away from Earth!”
Using a newly developed and extensive library of super-computer-generated images — three times larger than the library used for interpreting the 2017 observations — the team evaluated accretion models with data from both the 2017 and 2018 observations.
“When gas spirals into a black hole from afar, it can either flow in the same direction the black hole is rotating or in the opposite direction. We found that the latter case is more likely to match the multi-year observations thanks to their relatively higher turbulent variability,” explains León Sosapanta Salas, a PhD candidate at the University of Amsterdam. “Analysis of the EHT data for M87 from later years (2021 and 2022) is already underway and promises to provide even more robust statistical constraints and deeper insights into the nature of the turbulent flow surrounding the black hole of M87.”
Explore Further:
Reference: “The persistent shadow of the supermassive black hole of M87 – II. Model comparisons and theoretical interpretations” by Kazunori Akiyama, Ezequiel Albentosa-Ruíz, Antxon Alberdi, Walter Alef, Juan Carlos Algaba, Richard Anantua, Keiichi Asada, Rebecca Azulay, Uwe Bach, Anne-Kathrin Baczko, David Ball, Mislav Baloković, Bidisha Bandyopadhyay, John Barrett, Michi Bauböck, Bradford A. Benson, Dan Bintley, Lindy Blackburn, Raymond Blundell, Katherine L. Bouman, Geoffrey C. Bower, Michael Bremer, Roger Brissenden, Silke Britzen, Avery E. Broderick, Dominique Broguiere, Thomas Bronzwaer, Sandra Bustamante, John E. Carlstrom, Andrew Chael, Chi-kwan Chan, Dominic O. Chang, Koushik Chatterjee, Shami Chatterjee, Ming-Tang Chen, Yongjun Chen, Xiaopeng Cheng, Ilje Cho, Pierre Christian, Nicholas S. Conroy, John E. Conway, Thomas M. Crawford, Geoffrey B. Crew, Alejandro Cruz-Osorio, Yuzhu Cui, Brandon Curd, Rohan Dahale, Jordy Davelaar, Mariafelicia De Laurentis, Roger Deane, Jessica Dempsey, Gregory Desvignes, Jason Dexter, Vedant Dhruv, Indu K. Dihingia, Sheperd S. Doeleman, Sergio A. Dzib, Ralph P. Eatough, Razieh Emami, Heino Falcke, Joseph Farah, Vincent L. Fish, Edward Fomalont, H. Alyson Ford, Marianna Foschi, Raquel Fraga-Encinas, William T. Freeman, Per Friberg, Christian M. Fromm, Antonio Fuentes, Peter Galison, Charles F. Gammie, Roberto García, Olivier Gentaz, Boris Georgiev, Ciriaco Goddi, Roman Gold, Arturo I. Gómez-Ruiz, José L. Gómez, Minfeng Gu, Mark Gurwell, Kazuhiro Hada, Daryl Haggard, Ronald Hesper, Dirk Heumann, Luis C. Ho, Paul Ho, Mareki Honma, Chih-Wei L. Huang, Lei Huang, David H. Hughes, Shiro Ikeda, C. M. Violette Impellizzeri, Makoto Inoue, Sara Issaoun, David J. James, Buell T. Jannuzi, Michael Janssen, Britton Jeter, Wu Jiang, Alejandra Jiménez-Rosales, Michael D. Johnson, Svetlana Jorstad, Adam C. Jones, Abhishek V. Joshi, Taehyun Jung, Ramesh Karuppusamy, Tomohisa Kawashima, Garrett K. Keating, Mark Kettenis, Dong-Jin Kim, Jae-Young Kim, Jongsoo Kim, Junhan Kim, Motoki Kino, Jun Yi Koay, Prashant Kocherlakota, Yutaro Kofuji, Patrick M. Koch, Shoko Koyama, Carsten Kramer, Joana A. Kramer, Michael Kramer, Thomas P. Krichbaum, Cheng-Yu Kuo, Noemi La Bella, Sang-Sung Lee, Aviad Levis, Zhiyuan Li, Rocco Lico, Greg Lindahl, Michael Lindqvist, Mikhail Lisakov, Jun Liu, Kuo Liu, Elisabetta Liuzzo, Wen-Ping Lo, Andrei P. Lobanov, Laurent Loinard, Colin J. Lonsdale, Amy E. Lowitz, Ru-Sen Lu, Nicholas R. MacDonald, Jirong Mao, Nicola Marchili, Sera Markoff, Daniel P. Marrone, Alan P. Marscher, Iván Martí-Vidal, Satoki Matsushita, Lynn D. Matthews, Lia Medeiros, Karl M. Menten, Izumi Mizuno, Yosuke Mizuno, Joshua Montgomery, James M. Moran, Kotaro Moriyama, Monika Moscibrodzka, Wanga Mulaudzi, Cornelia Müller, Hendrik Müller, Alejandro Mus, Gibwa Musoke, Ioannis Myserlis, Hiroshi Nagai, Neil M. Nagar, Dhanya G. Nair, Masanori Nakamura, Gopal Narayanan, Iniyan Natarajan, Antonios Nathanail, Santiago Navarro Fuentes, Joey Neilsen, Chunchong Ni, Michael A. Nowak, Junghwan Oh, Hiroki Okino, Héctor Raúl Olivares Sánchez, Tomoaki Oyama, Feryal Özel, Daniel C. M. Palumbo, Georgios Filippos Paraschos, Jongho Park, Harriet Parsons, Nimesh Patel, Ue-Li Pen, Dominic W. Pesce, Vincent Piétu, Aleksandar PopStefanija, Oliver Porth, Ben Prather, Giacomo Principe, Dimitrios Psaltis, Hung-Yi Pu, Venkatessh Ramakrishnan, Ramprasad Rao, Mark G. Rawlings, Luciano Rezzolla, Angelo Ricarte, Bart Ripperda, Freek Roelofs, Cristina Romero-Cañizales, Eduardo Ros, Arash Roshanineshat, Helge Rottmann, Alan L. Roy, Ignacio Ruiz, Chet Ruszczyk, Kazi L. J. Rygl, Salvador Sánchez, David Sánchez-Argüelles, Miguel Sánchez-Portal, Mahito Sasada, Kaushik Satapathy, Tuomas Savolainen, F. Peter Schloerb, Jonathan Schonfeld, Karl-Friedrich Schuster, Lijing Shao, Zhiqiang Shen, Des Small, Bong Won Sohn, Jason SooHoo, León D. S. Salas, Kamal Souccar, Joshua S. Stanway, He Sun, Fumie Tazaki, Alexandra J. Tetarenko, Paul Tiede, Remo P. J. Tilanus, Michael Titus, Kenji Toma, Pablo Torne, Teresa Toscano, Efthalia Traianou, Tyler Trent, Sascha Trippe, Matthew Turk, Ilse van Bemmel, Huib Jan van Langevelde, Daniel R. van Rossum, Jesse Vos, Jan Wagner, Derek Ward-Thompson, John Wardle, Jasmin E. Washington, Jonathan Weintroub, Robert Wharton, Maciek Wielgus, Kaj Wiik, Gunther Witzel, Michael F. Wondrak, George N. Wong, Qingwen Wu, Nitika Yadlapalli, Paul Yamaguchi, Aristomenis Yfantis, Doosoo Yoon, André Young, Ziri Younsi, Wei Yu, Feng Yuan, Ye-Fei Yuan, J. Anton Zensus, Shuo Zhang, Guang-Yao Zhao and Shan-Shan Zhao, 22 January 2025, Astronomy & Astrophysics.
DOI: 10.1051/0004-6361/202451296
The Event Horizon Telescope (EHT) collaboration is a global effort involving over 400 researchers from across Africa, Asia, Europe, and the Americas. This international team aims to capture the most detailed images of black holes ever seen by creating a virtual telescope the size of Earth. By linking existing telescopes around the world with innovative technology, the EHT has achieved the highest angular resolution ever attained in astronomy, offering unprecedented views of black hole environments.
The EHT network includes several powerful telescopes: ALMA, APEX, the IRAM 30-meter Telescope, the IRAM NOEMA Observatory, the James Clerk Maxwell Telescope (JCMT), the Large Millimeter Telescope (LMT), the Submillimeter Array (SMA), the Submillimeter Telescope (SMT), the South Pole Telescope (SPT), the Kitt Peak Telescope, and the Greenland Telescope (GLT). The collected data were processed at the Max Planck Institute for Radio Astronomy (MPIfR) and the MIT Haystack Observatory, with further analysis carried out by an international team across multiple institutions.
The EHT consortium is composed of 13 leading research institutions that contribute to its success: the Academia Sinica Institute of Astronomy and Astrophysics, the University of Arizona, the University of Chicago, the East Asian Observatory, Goethe University Frankfurt, the Institut de Radioastronomie Millimétrique, the Large Millimeter Telescope, the Max Planck Institute for Radio Astronomy, the MIT Haystack Observatory, the National Astronomical Observatory of Japan, the Perimeter Institute for Theoretical Physics, Radboud University, and the Smithsonian Astrophysical Observatory.
Through this collaborative effort, the EHT continues to push the boundaries of our understanding of black holes, combining cutting-edge technology and global cooperation to explore some of the universe’s most mysterious phenomena.
