It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Thursday, April 27, 2023
Astronomers image for the first time a black hole’s shadow together with a powerful jet
VIDEO: ANIMATION SHOWING HOW THE EHT IMAGE OF M87* COMBINES WITH THE IMAGE FROM THE GMVA, WHERE THE CENTRAL BLACK HOLE CAN BE SEEN TOGETHER WITH THE BIRTH OF THE RELATIVISTIC OUTFLOW.view more
CREDIT: IVAN MARTI-VIDAL
"Previously we had seen both the black hole and the jet in separate images, but now we have taken a panoramic picture of the black hole together with its jet at a new wavelength”, says Ru-Sen Lu, from the Shanghai Astronomical Observatory and leader of a Max Planck Research Group at the Chinese Academy of Sciences. The surrounding material is thought to fall into the black hole in a process known as accretion. But no one has ever imaged it directly. "The ring that we have seen before is becoming larger and thicker at 3.5 mm observing wavelength. This shows that the material falling into the black hole produces additional emission that is now observed in the new image. This gives us a more complete view of the physical processes acting near the black hole”, he added.
The participation of ALMA and GLT in the GMVA observations and the resulting increase in resolution and sensitivity of this intercontinental network of telescopes has made it possible to image the ring-like structure in M87 for the first time at the wavelength of 3.5 mm. The diameter of the ring measured by the GMVA is 64 microarcseconds, which corresponds to the size of a small (5-inch/13-cm) selfie ring light as seen by an astronaut on the Moon looking back at Earth. This diameter is 50 percent larger than what was seen in observations by the Event Horizon Telescope at 1.3 mm, in accordance with the expectations for the emission from relativistic plasma in this region.
"With the greatly improved imaging capabilities by adding ALMA and GLT into GMVA observations, we have gained a new perspective. We do indeed see the triple-ridged jet that we knew about from earlier VLBI observations,” says Thomas Krichbaum from the Max Planck Institute for Radio Astronomy (MPIfR) in Bonn. "But now we can see how the jet emerges from the emission ring around the central supermassive black hole and we can measure the ring diameter also at another (longer) wavelength.”
The light from M87 is produced by the interplay between highly energetic electrons and magnetic fields, a phenomenon called synchrotron radiation. The new observations, at a wavelength of 3.5 mm, reveal more details about the location and energy of these electrons. They also tell us something about the nature of the black hole itself: it is not very hungry. It consumes matter at a low rate, converting only a small fraction of it into radiation. Keiichi Asada of Academia Sinica, Institute of Astronomy and Astrophysics explains: "To understand the physical origin of the bigger and thicker ring, we had to use computer simulations to test different scenarios. As a result, we concluded that the larger extent of the ring is associated with the accretion flow.”
Kazuhiro Hada from the National Astronomical Observatory of Japan adds: "We also find something surprising in our data: the radiation from the inner region close to the black hole is broader than we expected. This could mean that there is more than just gas falling in. There could also be a wind blowing out, causing turbulence and chaos around the black hole.”
The quest to learn more about Messier 87 is not over, as further observations and a fleet of powerful telescopes continue to unlock its secrets. “Future observations at millimetre wavelengths will study the time evolution of the M87 black hole and provide a poly-chromatic view of the black hole with multiple colour images in radio light," says Jongho Park of the Korea Astronomy and Space Science Institute.
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 für Radioastronomie (MPIfR), Institut de Radioastronomie Millimétrique (IRAM), Onsala Space Observatory (OSO), Metsähovi Radio Observatory (MRO), Yebes, the Korean VLBI Network (KVN), the Green Bank Telescope (GBT) and the Very Long Baseline Array (VLBA).
ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.
The Greenland Telescope (GLT) retrofit, rebuild, and operation are led by the Academia Sinica, Institute of Astronomy and Astrophysics (ASIAA) and the Smithsonian Astrophysical Observatory (SAO).
The Green Bank Observatory (GBT) and the National Radio Astronomy Observatory (VLBA) are major facilities of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.
The data were correlated at the Max Planck Institute for Radio Astronomy (MPIfR), which also operates the Global Millimeter-VLBI Array (GMVA).
The research team comprises Ru-Sen Lu, Keiichi Asada, Thomas P. Krichbaum, Jongho Park, Fumie Tazaki, Hung-Yi Pu, Masanori Nakamura, Andrei P. Lobanov, Kazuhiro Hada, Kazunori Akiyama, Jae-Young Kim, Iván Martí-Vidal, José L. Gómez, Tomohisa Kawashima, Feng Yuan, Eduardo Ros, Walter Alef, Silke Britzen, Michael Bremer, Avery Broderick, Akihiro Doi, Gabriele Giovannini, Marcello Giroletti, Paul Ho, Mareki Honma, David Hughes, Makoto Inoue, Wu Jiang, Motoki Kino, Shoko Koyama, Michael Lindqvist, Jun Liu, Alan 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 Chuter, John Conway, Geoffrey Crew, Jessica Dempsey, Sven Dornbusch, Aaron Faber, Per Friberg, Javier González-García, Miguel Gómez-Garrido, Chih-Chiang Han, Kuo-Chang Han, Yutaka Hasegawa, Ruben Herrero-Illana, Yau-De Huang, Chih-Wei Huang, Violette C.M. Impellizzeri, Homin Jiang, Hao Jinchi, Taehyun Jung, Juha Kallunki, Petri Kirves, Kimihiro Kimura, Jun Yi Koay, Patrick Koch, Carsten Kramer, Alexander Kraus, Derek Kubo, Cheng-Yu Kuo, Chao-Te Li, Chun-Che Lin, Ching-Tang Liu, Kuan-Yu Liu, Wen-Ping Lo, Li-Ming Lu, Nicholas R. MacDonald, Pierre Martin-Cocher, Hugo Messias, Zheng Meyer-Zhao, Anthony Minter, Dhanya Nair, Hiroaki Nishioka, Timothy Norton, George Nystrom, Hideo Ogawa, Peter Oshiro, Nimesh Patel, Ue-Li Pen, Yurii Pidopryhora, Nicolas Pradel, Philippe Raffin, Ramprasad Rao, Ignacio Ruiz, Salvador Sánchez, Paul Shaw, William Snow, T. K. Sridharan, Ranjani Srinivasan, Belén Tercero, Pablo Torne, Efthalia Traianou, Jan Wagner, Craig Walther, Ta-Shun Wei, Jun Yang, and Chen-Yu Yu.
IMAGE: ARTIST’S CONCEPTION SHOWS A CLOSE-UP VIEW OF THE ACCRETION FLOW AND THE JET EMERGING FROM THE BLACK HOLE REGION IN MESSIER 87view more
CREDIT: SOPHIA DAGNELLO, NRAO/AUI/NSF
An international team of scientists led by Dr. LU Rusen from the Shanghai Astronomical Observatory (SHAO) of the Chinese Academy of Sciences has used new millimeter-wavelength observations to produce an image that shows, for the first time, both the ring-like accretion structure around a black hole, where matter falls into the black hole, and the black hole's associated powerful relativistic jet. The source of the images was the central black hole of the prominent radio galaxy Messier 87.
The image underlines for the first time the connection between the accretion flow near the central supermassive black hole and the origin of the jet. The new observations were obtained with the Global Millimeter VLBI Array (GMVA), complemented by the phased Atacama Large Millimeter/submillimeter Array (ALMA) and the Greenland Telescope (GLT). The addition of these two observatories has greatly enhanced the imaging capabilities of the GMVA.
"Previously, we had seen both the black hole and the jet in separate images, but now we have taken a panoramic picture of the black hole together with its jet at a new wavelength," said Dr. LU.
The surrounding material is thought to fall into the black hole in a process known as accretion. But no one had ever imaged it directly.
According to LU, the ring that was seen before was becoming larger and thicker at the 3.5 mm observing wavelength. "This shows that the material falling into the black hole produces additional emission that is now observed in the new image. This gives us a more complete view of the physical processes acting near the black hole," said LU.
The participation of ALMA and GLT in the GMVA observations and the resulting increase in resolution and sensitivity of this intercontinental network of telescopes has made it possible to image the ring-like structure in M87 for the first time at the 3.5 mm wavelength. The diameter of the ring measured by the GMVA is 64 microarcseconds, which corresponds to the size of a small (5-inch/13-cm) selfie ring light on Earth as seen by an astronaut on the Moon. This diameter is 50 percent larger than what was seen in observations by the Event Horizon Telescope at 1.3 mm, in accordance with expectations for the emission from relativistic plasma in this region.
"With the greatly improved imaging capabilities by adding ALMA and GLT into GMVA observations, we have gained a new perspective. We do indeed see the triple-ridged jet that we knew about from earlier VLBI observations," said Thomas Krichbaum of the Max Planck Institute for Radio Astronomy (MPIfR) in Bonn. "But now we can see how the jet emerges from the emission ring around the central supermassive black hole and we can measure the ring diameter also at another (longer) wavelength."
The light from M87 is produced by the interplay between highly energetic electrons and magnetic fields, a phenomenon called synchrotron radiation. The new observations, at a wavelength of 3.5 mm, reveal more details about the location and energy of these electrons. They also tell us something about the nature of the black hole itself: It is not very hungry. It consumes matter at a low rate, converting only a small fraction of it into radiation.
According to Keiichi Asada from the Institute of Astronomy and Astrophysics of Academia Sinica, "To understand the physical origin of the bigger and thicker ring, we had to use computer simulations to test different scenarios. As a result, we concluded that the larger extent of the ring is associated with the accretion flow."
Kazuhiro Hada from the National Astronomical Observatory of Japan noted that the team also found something "surprising" in their data. "The radiation from the inner region close to the black hole is broader than we expected. This could mean that there is more than just gas falling in. There could also be a wind blowing out, causing turbulence and chaos around the black hole," said Hada.
The quest to learn more about Messier 87 is not over, as further observations and a fleet of powerful telescopes continue to unlock its secrets. "Future observations at millimeter wavelengths will study the time evolution of the M87 black hole and provide a polychromatic view of the black hole with multiple color images in radio light," said Jongho Park of the Korea Astronomy and Space Science Institute.
Millimeter-VLBI image of the jet and the black hole in Messier 87, obtained with the GMVA array plus ALMA and the Greenland Telescope
CREDIT
LU Rusen, SHAO; E. Ros, MPIfR; and S. Dagnello, NRAO/AUI/NSF
Map of the radio telescopes used to image Messier 87 at 3.5 millimeters in the 2018 Global Millimeter VLBI Array (GMVA) campaign
CREDIT
Helge Rottmann, MPIfR
How the Messier 87 black hole and jet image was captured
VIDEO: METSÄHOVI RADIO TELESCOPE, LOCATED IN THE FORESTS OUTSIDE GREATER HELSINKI IN FINLAND, IS ONE OF THE TELESCOPES USED TO TAKE THE FIRST IMAGE OF THE M87 BLACK HOLE TOGETHER WITH ITS POWERFUL JET. THE IMAGE IS FORMED FROM MEASUREMENTS GATHERED AT 3.5MM RADIO WAVELENGTH BY A NETWORK OF RADIO TELESCOPES AROUND THE WORLD. THE RESULTS WERE PUBLISHED IN NATURE ON 26 APRIL 2023.view more
In 2017, astronomers captured the first image of a black hole by coordinating radio dishes around the world to act as a single, planet-sized telescope. The synchronized network, known collectively as the Event Horizon Telescope (EHT), focused in on M87*, the black hole at the center of the nearby Messier 87 galaxy. The telescope’s laser-focused resolution revealed a very thin glowing ring around a dark center, representing the first visual of a black hole’s shadow.
Astronomers have now refocused their view to capture a new layer of M87*. The team, including scientists at MIT’s Haystack Observatory, has harnessed another global web of observatories — the Global millimeter VLBI Array (GMVA) — to capture a more zoomed-out view of the black hole.
The new images, taken one year after the EHT’s initial observations, reveal a thicker, fluffier ring that is 50 percent larger than the ring that was first reported. This larger ring is a reflection of the telescope array’s resolution, which was tuned to pick up more of the super-hot, glowing plasma surrounding the black hole.
For the first time, scientists could see that part of the black hole’s ring consists of plasma from a surrounding accretion disk — a swirling pancake of white-hot electrons that the team estimates is being heated to hundreds of billions of Kelvin as the plasma streams into the black hole at close to the speed of light.
The images also reveal plasma trailing out from the central ring, which scientists believe to be part of a relativistic jet blasting out from the black hole. The scientists tracked these emissions back toward the black hole and observed for the first time that the base of the jet appears to connect to the central ring.
“This is the first image where we are able to pin down where the ring is, relative to the powerful jet escaping out of the central black hole,” says Kazunori Akiyama, a research scientist at MIT’s Haystack Observatory, who developed the imaging software used to visualize the black hole. “Now we can start to address questions such as how particles are accelerated and heated, and many other mysteries around the black hole, more deeply.”
Akiyama is part of an international team of astronomers who present the new images, along with their analysis, in a paper that will appear in Nature.
An expanded eye
To capture images of M87*, astronomers used a technique in radio astronomy known as very-long-baseline interferometry, or VLBI. When a radio signal passes by Earth, such as from a black hole’s plasma emissions, radio dishes around the world can pick up the signal. Scientists can then determine the time at which each dish registers the signal, and the distance between dishes, and combine this information in a way that the same signal is seen by every dish simultaneously as one very large, planet-scale telescope.
When each radio telescope is dialed to a specific frequency, the array as a whole can focus in on a particular feature of the radio signal. The EHT’s network was tuned to 1.3 millimeters — a resolution equivalent to seeing a grain of rice in California, from Massachusetts. At this resolution, astronomers could see past most of the plasma surrounding M87* and image the thinnest ring, thereby accentuating the black hole’s shadow.
In contrast, the GMVA network works at a slightly lower resolution of 3 millimeters. With this focus, the array could resolve a pumpkin seed, rather than a grain of rice. The network itself consists of about a dozen radio telescopes scattered around the United States and Europe, mostly located along the east-west axis of the Earth. To make a truly planet-sized telescope able to capture a far-off radio signal from M87*, astronomers had to expand the array’s “eye” to the north and south.
To do so, the team involved two additional radio observatories: the Greenland Telescope to the north, and the Atacama Large Millimeter/submillimeter Array (ALMA) to the south. ALMA is an array of 66 radio dishes located in Chile’s Atacama Desert. MIT Haystack scientists, led by research scientist Lynn Matthews, worked to phase, or synchronize, ALMA’s dishes to work as one powerful and essential part of the GMVA network.
“Having these two telescopes [as part of] the global array resulted in a boost in angular resolution by a factor of four in the north-south direction,” Matthews says. “This greatly improves the level of detail we can see. And in this case, a consequence was a dramatic leap in our understanding of the physics operating near the black hole at the center of the M87 galaxy.”
Tuning in
On April 14 and 15 of 2018, astronomers coordinated the telescopes of the GMVA, along with the Greenland and ALMA observatories, to record radio emissions at a wavelength of 3 millimeters, arriving from the direction of the M87 galaxy. Scientists then used several imaging-processing algorithms, including the Sparse Modeling Imaging Library for Interferometry (SMILI) — an imaging software package developed by Akiyama — to process the GMVA’s observations into visual images.
The resulting pictures reveal more plasma surrounding the black hole, in the form of a larger, fluffier ring. The astronomers could also spot plasma trailing up and out from the central glowing ring.
“The exciting thing is, we still see a shadow feature of the black hole, but we also start to see a more extended jet,” Akiyama says. “For plasma to emit light at this wavelength, it has to be very heated, such that each particle in the plasma travels almost at the speed of light. So particles are accelerated to relativistic speeds. And we see that in the case of M87, this jet is extending and traveling across a really large scale.”
The astronomers hope to pin down more properties of the black hole’s plasma, such as its temperature profile and composition. For this, they plan to tune the EHT and GMVA to new resolutions. By observing M87* at multiple wavelengths, they can then construct a layered picture, and a more detailed understanding of black holes and the jets they generate.
“If something major happens in the world, you might tune in to both AM and FM to assemble a ‘complete picture’ of the event,” says Geoffrey Crews, a Haystack research scientist who works to support ALMA and the EHT. “This is no different. You might think of the EHT M87* image being made in FM, and this result coming from AM. Both tell a story, and together it is a better story.”
###
Written by Jennifer Chu, MIT News Office
JOURNAL
Nature
ARTICLE TITLE
“A ring-like accretion structure in M87 connecting its black hole and jet”
First direct image of a black hole expelling a powerful jet
IMAGE: THIS IMAGE SHOWS THE JET AND SHADOW OF THE BLACK HOLE AT THE CENTRE OF THE M87 GALAXY TOGETHER FOR THE FIRST TIME. THE OBSERVATIONS WERE OBTAINED WITH TELESCOPES FROM THE GLOBAL MILLIMETRE VLBI ARRAY (GMVA), THE ATACAMA LARGE MILLIMETER/SUBMILLIMETER ARRAY (ALMA), OF WHICH ESO IS A PARTNER, AND THE GREENLAND TELESCOPE. THIS IMAGE GIVES SCIENTISTS THE CONTEXT NEEDED TO UNDERSTAND HOW THE POWERFUL JET IS FORMED. THE NEW OBSERVATIONS ALSO REVEALED THAT THE BLACK HOLE’S RING, SHOWN HERE IN THE INSET, IS 50% LARGER THAN THE RING OBSERVED AT SHORTER RADIO WAVELENGTHS BY THE EVENT HORIZON TELESCOPE (EHT). THIS SUGGESTS THAT IN THE NEW IMAGE WE SEE MORE OF THE MATERIAL THAT IS FALLING TOWARDS THE BLACK HOLE THAN WHAT WE COULD SEE WITH THE EHT.view more
CREDIT: R.-S. LU (SHAO), E. ROS (MPIFR), S. DAGNELLO (NRAO/AUI/NSF)
For the first time, astronomers have observed, in the same image, the shadow of the black hole at the centre of the galaxy Messier 87 (M87) and the powerful jet expelled from it. The observations were done in 2018 with telescopes from the Global Millimetre VLBI Array (GMVA), the Atacama Large Millimeter/submillimeter Array (ALMA), of which ESO is a partner, and the Greenland Telescope (GLT). Thanks to this new image, astronomers can better understand how black holes can launch such energetic jets.
Most galaxies harbour a supermassive black hole at their centre. 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 neighbourhood, 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.
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 M87’s 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 centre 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 towards the black hole than what could be observed with the EHT.
These new observations of M87’s black hole were conducted in 2018 with the GMVA, which consists of 14 radio-telescopes in Europe and North America [1]. 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 synchronises the signals taken by each individual facility. But to properly capture the actual shape of an astronomical object it’s 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 M87’s black hole. “Thanks to ALMA’s 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 centre 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.
Notes
[1] The Korean VLBI Network is now also part of the GMVA, but did not participate in the observations reported here.
More information
This research was presented in the paper "A ring-like accretion structure in M87 connecting its black hole and jet" to appear in Nature (doi: 10.1038/s41586-023-05843-w)
The team is composed of Ru-Sen Lu (Shanghai Astronomical Observatory, People’s Republic of China [Shanghai]; Key Laboratory of Radio Astronomy, People’s Republic of China [KLoRA]; Max-Planck-Institut für 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 d’Astronomia i Astrofísica, Universitat de València, Spain; Observatori Astronòmic, Universitat de València, Spain), Jose L. Gomez (Instituto de Astrofísica de Andalucía-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, People’s Republic of China; School of Astronomy and Space Sciences, University of Chinese Academy of Sciences, People’s Republic of China [SoAaSS]), Eduardo Ros (MPIfR), Walter Alef (MPIfR), Silke Britzen (MPIfR), Michael Bremer (Institut de Radioastronomie Millimétrique, France [IRAMF]), Avery E. Broderick (Department of Physics and Astronomy, University of Waterloo, Canada [Waterloo]; Waterloo Centre for Astrophysics, University of Waterloo, Canada; Perimeter Institute for Theoretical Physics, Canada), Akihiro Doi (The Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Japan; Department of Space and Astronautical Science, SOKENDAI, Japan [SOKENDAI]), Gabriele Giovannini (Dipartimento di Fisica e Astronomia, Università di Bologna, Italy; Istituto di Radio Astronomia, INAF, Bologna, Italy [INAF]), Marcello Giroletti (INAF), Paul T. P. Ho (IoAaA), Mareki Honma (Mizusawa; Hachinohe; Department of Astronomy, The University of Tokyo, Japan), David H. Hughes (Instituto Nacional de Astrofísica, Mexico), Makoto Inoue (IoAaA), Wu Jiang (Shanghai), Motoki Kino (NAOoJ; Kogakuin University of Technology and Engineering, Japan), Shoko Koyama (Niigata University, Japan; IoAaA), Michael Lindqvist (Department of Space, Earth and Environment, Chalmers University of Technology, Sweden [Chalmers]), Jun Liu (MPIfR), Alan P. Marscher (Institute for Astrophysical Research, Boston University, USA), Satoki Matsushita (IoAaA), Hiroshi Nagai (NAOoJ; SOKENDAI), Helge Rottmann (MPIfR), Tuomas Savolainen (Department of Electronics and Nanoengineering, Aalto University, Finland; Metsähovi Radio Observatory, Finland [Metsähovi]; MPIfR), Karl-Friedrich Schuster (IRAMF), Zhi-Qiang Shen (Shanghai; KLoRA), Pablo de Vicente (Observatorio de Yebes, Spain [Yebes]), R. Craig Walker (National Radio Astronomy Observatory, Socorro, USA), Hai Yang (Shanghai; SoAaSS), J. Anton Zensus (MPIfR), Juan Carlos Algaba (Department of Physics, Universiti Malaya, Malaysia), Alexander Allardi (University of Vermont, USA), Uwe Bach (MPIfR), Ryan Berthold (East Asian Observatory, USA [EAO]), Dan Bintley (EAO), Do-Young Byun (KAaSSI; University of Science and Technology, Daejeon, Republic of Korea), Carolina Casadio (Institute of Astrophysics, Heraklion, Greece; Department of Physics, University of Crete, Greece), Shu-Hao Chang (IoAaA), Chih-Cheng Chang (National Chung-Shan Institute of Science and Technology, Taiwan, ROC [Chung-Shan]), Song-Chu Chang (Chung-Shan), Chung-Chen Chen (IoAaA), Ming-Tang Chen (Institute of Astronomy and Astrophysics, Academia Sinica, USA [IAAAS]), Ryan Chilson (IAAAS), Tim C. Chuter (EAO), John Conway (Chalmers), Geoffrey B. Crew (Haystack), Jessica T. Dempsey (EAO; Astron, The Netherlands [Astron]), Sven Dornbusch (MPIfR), Aaron Faber (Western University, Canada), Per Friberg (EAO), Javier González García (Yebes), Miguel Gómez Garrido (Yebes), Chih-Chiang Han (IoAaA), Kuo-Chang Han (System Development Center, National Chung-Shan Institute of Science and Technology, Taiwan, ROC), Yutaka Hasegawa (Osaka Metropolitan University, Japan [Osaka]), Ruben Herrero-Illana (European Southern Observatory, Chile), Yau-De Huang (IoAaA), Chih-Wei L. Huang (IoAaA), Violette Impellizzeri (Leiden Observatory, the Netherlands; National Radio Astronomy Observatory, Charlottesville, USA [NRAOC]), Homin Jiang (IoAaA), Hao Jinchi (Electronic Systems Research Division, National Chung-Shan Institute of Science and Technology, Taiwan, ROC), Taehyun Jung (KAaSSI), Juha Kallunki (Metsähovi), Petri Kirves (Metsähovi), Kimihiro Kimura (Japan Aerospace Exploration Agency, Japan), Jun Yi Koay (IoAaA), Patrick M. Koch (IoAaA), Carsten Kramer (IRAMF), Alex Kraus (MPIfR), Derek Kubo (IAAAS), Cheng-Yu Kuo (National Sun Yat-Sen University, Taiwan, ROC), Chao-Te Li (IoAaA), Lupin Chun-Che Lin (Department of Physics, National Cheng Kung University, Taiwan, ROC ), Ching-Tang Liu (IoAaA), Kuan-Yu Liu (IoAaA), Wen-Ping Lo (Department of Physics, National Taiwan University, Taiwan, ROC; IoAaA), Li-Ming Lu (Chung-Shan), Nicholas MacDonald (MPIfR), Pierre Martin-Cocher (IoAaA), Hugo Messias (Joint ALMA Observatory, Chile; Osaka), Zheng Meyer-Zhao (Astron; IoAaA), Anthony Minter (Green Bank Observatory, USA), Dhanya G. Nair (Astronomy Department, Universidad de Concepción, Chile), Hiroaki Nishioka (IoAaA), Timothy J. Norton (Center for Astrophysics | Harvard & Smithsonian, USA [CfA]), George Nystrom (IAAAS), Hideo Ogawa (Osaka), Peter Oshiro (IAAAS), Nimesh A. Patel (CfA), Ue-Li Pen (IoAaA), Yurii Pidopryhora (MPIfR; Argelander-Institut für Astronomie, Universität Bonn, Germany), Nicolas Pradel (IoAaA), Philippe A. Raffin (IAAAS), Ramprasad Rao (CfA), Ignacio Ruiz (Institut de Radioastronomie Millimétrique, Granada, Spain [IRAMS]), Salvador Sanchez (IRAMS), Paul Shaw (IoAaA), William Snow (IAAAS), T. K. Sridharan (NRAOC; CfA), Ranjani Srinivasan (CfA; IoAaA), Belén Tercero (Yebes), Pablo Torne (IRAMS), Thalia Traianou (IAA; MPIfR), Jan Wagner (MPIfR), Craig Walther (EAO), Ta-Shun Wei (IoAaA), Jun Yang (Chalmers), Chen-Yu Yu (IoAaA).
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 für Radioastronomie (MPIfR), Institut de Radioastronomie Millimétrique (IRAM), Onsala Space Observatory (OSO), Metsähovi Radio Observatory (MRO), Yebes, the Korean VLBI Network (KVN), the Green Bank Telescope (GBT) and the Very Long Baseline Array (VLBA).
The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of ESO, the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science and Technology Council (NSTC) in Taiwan and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI). ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.
The Greenland Telescope (GLT) retrofit, rebuild, and operation are led by the Academia Sinica, Institute of Astronomy and Astrophysics (ASIAA) and the Smithsonian Astrophysical Observatory (SAO).
The European Southern Observatory (ESO) enables scientists worldwide to discover the secrets of the Universe for the benefit of all. We design, build and operate world-class observatories on the ground — which astronomers use to tackle exciting questions and spread the fascination of astronomy — and promote international collaboration in astronomy. Established as an intergovernmental organisation in 1962, today ESO is supported by 16 Member States (Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom), along with the host state of Chile and with Australia as a Strategic Partner. ESO’s headquarters and its visitor centre and planetarium, the ESO Supernova, are located close to Munich in Germany, while the Chilean Atacama Desert, a marvellous place with unique conditions to observe the sky, hosts our telescopes. ESO operates three observing sites: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its Very Large Telescope Interferometer, as well as survey telescopes such as VISTA. Also at Paranal ESO will host and operate the Cherenkov Telescope Array South, the world’s largest and most sensitive gamma-ray observatory. Together with international partners, ESO operates ALMA on Chajnantor, a facility that observes the skies in the millimetre and submillimetre range. At Cerro Armazones, near Paranal, we are building “the world’s biggest eye on the sky” — ESO’s Extremely Large Telescope. From our offices in Santiago, Chile we support our operations in the country and engage with Chilean partners and society.
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