In a historic first, astronomers have simultaneously imaged the shadow and jet of the supermassive
Most galaxies harbor a supermassive black hole at their center. While black holes are known for engulfing matter in their immediate vicinity, they can also launch powerful jets of matter that extend beyond the galaxies that they live in. Understanding how black holes create such enormous jets has been a long-standing problem in astronomy. We know that jets are ejected from the region surrounding black holes, says Ru-Sen Lu from the Shanghai Astronomical Observatory in China, but we still do not fully understand how this actually happens. To study this directly we need to observe the origin of the jet as close as possible to the black hole.
The new image published today shows precisely this for the first time: how the base of a jet connects with the matter swirling around a supermassive black hole. The target is the galaxy M87, located 55 million light-years away in our cosmic neighborhood, and home to a black hole 6.5 billion times more massive than the Sun. Previous observations had managed to separately image the region close to the black hole and the jet, but this is the first time both features have been observed together. This new image completes the picture by showing the region around the black hole and the jet at the same time, adds Jae-Young Kim from the Kyungpook National University in South Korea and the Max Planck Institute for Radio Astronomy in Germany.
With the help of ALMA, astronomers have obtained a new image of the supermassive black hole at the center of the M87 galaxy. Credit: ESO
The image was obtained with the GMVA, ALMA, and the GLT, forming a network of radio telescopes around the globe working together as a virtual Earth-sized telescope. Such a large network can discern very small details in the region around M87s black hole.
The new image shows the jet emerging near the black hole, as well as what scientists call the shadow of the black hole. As matter orbits the black hole, it heats up and emits light. The black hole bends and captures some of this light, creating a ring-like structure around the black hole as seen from Earth. The darkness at the center of the ring is the black hole shadow, which was first imaged by the Event Horizon Telescope (EHT) in 2017. Both this new image and the EHT one combine data taken with several radio telescopes worldwide, but the image released today shows radio light emitted at a longer wavelength than the EHT one: 3.5 mm instead of 1.3 mm. At this wavelength, we can see how the jet emerges from the ring of emission around the central supermassive black hole, says Thomas Krichbaum of the Max Planck Institute for Radio Astronomy.
The size of the ring observed by the GMVA network is roughly 50% larger in comparison to the Event Horizon Telescope image. To understand the physical origin of the bigger and thicker ring, we had to use computer simulations to test different scenarios, explains Keiichi Asada from the Academia Sinica in Taiwan. The results suggest the new image reveals more of the material that is falling toward the black hole than what could be observed with the EHT.
This zoom video starts with a view of ALMA and zooms in on the heart of the M87 galaxy, showing successively more detailed observations. The final image shows the shadow of the black hole and a powerful jet expelled from it, together for the first time in the same image. The observations were obtained with telescopes from the Global Millimetre VLBI Array (GMVA), ALMA, of which ESO is a partner, and the Greenland Telescope. Credit: ESO
These new observations of M87s black hole were conducted in 2018 with the GMVA, which consists of 14 radio telescopes in Europe and North America. In addition, two other facilities were linked to the GMVA: the Greenland Telescope and ALMA, of which ESO is a partner. ALMA consists of 66 antennas in the Chilean Atacama desert, and it played a key role in these observations. The data collected by all these telescopes worldwide are combined using a technique called interferometry, which synchronizes the signals taken by each individual facility. But to properly capture the actual shape of an astronomical object its important that the telescopes are spread all over the Earth. The GMVA telescopes are mostly aligned East-to-West, so the addition of ALMA in the Southern hemisphere proved essential to capture this image of the jet and shadow of M87s black hole. Thanks to ALMAs location and sensitivity, we could reveal the black hole shadow and see deeper into the emission of the jet at the same time, explains Lu.
Future observations with this network of telescopes will continue to unravel how supermassive black holes can launch powerful jets. We plan to observe the region around the black hole at the center of M87 at different radio wavelengths to further study the emission of the jet, says Eduardo Ros from the Max Planck Institute for Radio Astronomy. Such simultaneous observations would allow the team to disentangle the complicated processes that happen near the supermassive black hole. The coming years will be exciting, as we will be able to learn more about what happens near one of the most mysterious regions in the Universe, concludes Ros.
- The Korean VLBI Network is now also part of the GMVA, but did not participate in the observations reported here.
Reference: A ring-like accretion structure in M87 connecting its black hole and jet by Ru-Sen Lu, Keiichi Asada, Thomas P. Krichbaum, Jongho Park, Fumie Tazaki, Hung-Yi Pu, Masanori Nakamura, Andrei Lobanov, Kazuhiro Hada, Kazunori Akiyama, Jae-Young Kim, Ivan Marti-Vidal, Jos L. Gmez, Tomohisa Kawashima, Feng Yuan, Eduardo Ros, Walter Alef, Silke Britzen, Michael Bremer, Avery E. Broderick, Akihiro Doi, Gabriele Giovannini, Marcello Giroletti, Paul T. P. Ho, Mareki Honma, David H. Hughes, Makoto Inoue, Wu Jiang, Motoki Kino, Shoko Koyama, Michael Lindqvist, Jun Liu, Alan P. Marscher, Satoki Matsushita, Hiroshi Nagai, Helge Rottmann, Tuomas Savolainen, Karl-Friedrich Schuster, Zhi-Qiang Shen, Pablo de Vicente, R. Craig Walker, Hai Yang, J. Anton Zensus, Juan Carlos Algaba, Alexander Allardi, Uwe Bach, Ryan Berthold, Dan Bintley, Do-Young Byun, Carolina Casadio, Shu-Hao Chang, Chih-Cheng Chang, Song-Chu Chang, Chung-Chen Chen, Ming-Tang Chen, Ryan Chilson, Tim C. Chuter, John Conway, Geoffrey B. Crew, Jessica T. Dempsey, Sven Dornbusch, Aaron Faber, Per Friberg, Javier Gonzlez Garca, Miguel Gmez Garrido, Chih-Chiang Han, Kuo-Chang Han, Yutaka Hasegawa, Ruben Herrero-Illana, Yau-De Huang, Chih-Wei L. Huang, Violette Impellizzeri, Homin Jiang, Hao Jinchi, Taehyun Jung, Juha Kallunki, Petri Kirves, Kimihiro Kimura, Jun Yi Koay, Patrick M. Koch, Carsten Kramer, Alex Kraus, Derek Kubo, Cheng-Yu Kuo, Chao-Te Li, Lupin Chun-Che Lin, Ching-Tang Liu, Kuan-Yu Liu, Wen-Ping Lo, Li-Ming Lu, Nicholas MacDonald, Pierre Martin-Cocher, Hugo Messias, Zheng Meyer-Zhao, Anthony Minter, Dhanya G. Nair, Hiroaki Nishioka, Timothy J. Norton, George Nystrom, Hideo Ogawa, Peter Oshiro, Nimesh A. Patel, Ue-Li Pen, Yurii Pidopryhora, Nicolas Pradel, Philippe A. Raffin, Ramprasad Rao, Ignacio Ruiz, Salvador Sanchez, Paul Shaw, William Snow, T. K. Sridharan, Ranjani Srinivasan, Beln Tercero, Pablo Torne, Efthalia Traianou, Jan Wagner, Craig Walther, Ta-Shun Wei, Jun Yang and Chen-Yu Yu, 26 April 2023, Nature.
This research has made use of data obtained with the Global Millimeter VLBI Array (GMVA), which consists of telescopes operated by the Max-Planck-Institut fr Radioastronomie (MPIfR), Institut de Radioastronomie Millimtrique (IRAM), Onsala Space Observatory (OSO), Metshovi Radio Observatory (MRO), Yebes, the Korean VLBI Network (KVN), the Green Bank Telescope (GBT) and the Very Long Baseline Array (VLBA).
The team is composed of Ru-Sen Lu (Shanghai Astronomical Observatory, Peoples Republic of China [Shanghai]; Key Laboratory of Radio Astronomy, Peoples Republic of China [KLoRA]; Max-Planck-Institut fr Radioastronomie, Germany [MPIfR]), Keiichi Asada (Institute of Astronomy and Astrophysics, Academia Sinica, Taiwan, ROC [IoAaA]), Thomas P. Krichbaum (MPIfR), Jongho Park (IoAaA; Korea Astronomy and Space Science Institute, Republic of Korea [KAaSSI]), Fumie Tazaki (Simulation Technology Development Department, Tokyo Electron Technology Solutions Ltd., Japan; Mizusawa VLBI Observatory, National Astronomical Observatory of Japan, Japan [Mizusawa]), Hung-Yi Pu (Department of Physics, National Taiwan Normal University, Taiwan, ROC; IoAaA; Center of Astronomy and Gravitation, National Taiwan Normal University, Taiwan, ROC), Masanori Nakamura (National Institute of Technology, Hachinohe College, Japan; IoAaA), Andrei Lobanov (MPIfR), Kazuhiro Hada (Mizusawa; Department of Astronomical Science, The Graduate University for Advanced Studies, Japan), Kazunori Akiyama (Black Hole Initiative at Harvard University, USA; Massachusetts Institute of Technology Haystack Observatory, USA [Haystack]; National Astronomical Observatory of Japan, Japan [NAOoJ]), Jae-Young Kim (Department of Astronomy and Atmospheric Sciences, Kyungpook National University, Republic of Korea; KAaSSI; MPIfR), Ivan Marti-Vidal (Departament dAstronomia i Astrofsica, Universitat de Valncia, Spain; Observatori Astronmic, Universitat de Valncia, Spain), Jose L. Gomez (Instituto de Astrofsica de Andaluca-CSIC, Spain [IAA]), Tomohisa Kawashima (Institute for Cosmic Ray Research, The University of Tokyo, Japan), Feng Yuan (Shanghai; Key Laboratory for Research in Galaxies and Cosmology, Chinese Academy of Sciences, Peoples Republic of China; School of Astronomy and Space Sciences, University of Chinese Academy of Sciences, Peoples Republic of China [SoAaSS]), Eduardo Ros (MPIfR), Walter Alef (MPIfR), Silke Britzen (MPIfR), Michael Bremer (Institut de Radioastronomie Millimtrique, France [IRAMF]), Avery E. Broderick (Department of Physics and Astronomy,