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First M87 Event Horizon Telescope Results. II. Array and Instrumentation

The Astrophysical Journal Letters · 2019 · Vol. 875(1) · pp. L2–L2

Kazunori Akiyama✉(Woodwell Climate Research Center)A. Alberdi(Instituto de Astrofísica de Andalucía)W. Alef(Max Planck Institute for Radio Astronomy)Keiichi Asada(Institute of Astronomy and Astrophysics, Academia Sinica)Rebecca Azulay(Universitat de València)Anne-Kathrin Baczko(Max Planck Institute for Radio Astronomy)David Ball(University of Arizona)Mislav Baloković(Woodwell Climate Research Center)John Barrett(Massachusetts Institute of Technology)Dan Bintley(East Asian Observatory)Lindy Blackburn(Woodwell Climate Research Center)W. Boland(Nederlandse Onderzoekschool Voor Astronomie)Katherine L. Bouman(California Institute of Technology)Geoffrey C. BowerMichael Bremer(Institut de Radioastronomie Millimétrique)Christiaan D. Brinkerink(Radboud University Nijmegen)Roger Brissenden(Woodwell Climate Research Center)S. Britzen(Max Planck Institute for Radio Astronomy)Avery E. Broderick(University of Waterloo)Dominique Broguière(Institut de Radioastronomie Millimétrique)Thomas Bronzwaer(Radboud University Nijmegen)Do‐Young Byun(Korea Astronomy and Space Science Institute)J. E. Carlstrom(Fermi National Accelerator Laboratory)Andrew Chael(Woodwell Climate Research Center)Chi‐kwan Chan(University of Arizona)Shami Chatterjee(Cornell University)Koushik Chatterjee(University of Amsterdam)Ming‐Tang ChenXiaopeng Cheng(Chinese Academy of Sciences)Ilje Cho(Korea Astronomy and Space Science Institute)Pierre Christian(University of Arizona)J. E. Conway(Chalmers University of Technology)J. M. Cordes(Cornell University)G. Crew(Massachusetts Institute of Technology)Yuzhu Cui(The Graduate University for Advanced Studies, SOKENDAI)Jordy Davelaar(Radboud University Nijmegen)Mariafelicia De Laurentis(Goethe University Frankfurt)Roger Deane(Rhodes University)Jessica Dempsey(East Asian Observatory)G. Desvignes(Max Planck Institute for Radio Astronomy)Jason Dexter(Max Planck Institute for Extraterrestrial Physics)Sheperd S. Doeleman(Woodwell Climate Research Center)Ralph P. Eatough(Max Planck Institute for Radio Astronomy)H. Falcke(Radboud University Nijmegen)Vincent L. Fish(Massachusetts Institute of Technology)Ed Fomalont(National Radio Astronomy Observatory)Raquel Fraga-Encinas(Radboud University Nijmegen)Per Friberg(East Asian Observatory)Christian M. Fromm(Goethe University Frankfurt)José L. Gómez(Instituto de Astrofísica de Andalucía)Peter Galison(Woodwell Climate Research Center)Charles F. Gammie(University of Illinois Urbana-Champaign)Roberto García(Institut de Radioastronomie Millimétrique)Olivier Gentaz(Institut de Radioastronomie Millimétrique)Boris Georgiev(University of Waterloo)C. Goddi(Leiden University)Roman Gold(Goethe University Frankfurt)Minfeng Gu(Chinese Academy of Sciences)Mark Gurwell(Center for Astrophysics Harvard & Smithsonian)Kazuhiro Hada(The Graduate University for Advanced Studies, SOKENDAI)M. H. Hecht(Massachusetts Institute of Technology)Ronald Hesper(University of Groningen)Luis C. Ho(Peking University)Paul T. P. Ho(Institute of Astronomy and Astrophysics, Academia Sinica)Mareki Honma(The Graduate University for Advanced Studies, SOKENDAI)Chih-Wei L. Huang(Institute of Astronomy and Astrophysics, Academia Sinica)Lei 磊 Huang 黄(Chinese Academy of Sciences)D. H. Hughes(National Institute of Astrophysics, Optics and Electronics)Shiro Ikeda(Kavli Institute for the Physics and Mathematics of the Universe)Makoto Inoue(Institute of Astronomy and Astrophysics, Academia Sinica)Sara Issaoun(Radboud University Nijmegen)D. J. James(Woodwell Climate Research Center)Buell T. Jannuzi(University of Arizona)Michaël Janssen(Radboud University Nijmegen)Britton Jeter(University of Waterloo)Wu Jiang(Shanghai Astronomical Observatory)Michael D. Johnson(Woodwell Climate Research Center)Svetlana G. Jorstad(Boston University)Taehyun Jung(Korea Astronomy and Space Science Institute)Mansour Karami(University of Waterloo)R. Karuppusamy(Max Planck Institute for Radio Astronomy)Tomohisa Kawashima(National Astronomical Observatory of Japan)Garrett K. Keating(Center for Astrophysics Harvard & Smithsonian)Mark Kettenis(Joint Institute for VLBI ERIC)Jae-Young Kim(Max Planck Institute for Radio Astronomy)Junhan Kim(University of Arizona)Jongsoo Kim(Korea Astronomy and Space Science Institute)Motoki Kino(Kogakuin University)Jun Yi Koay(Institute of Astronomy and Astrophysics, Academia Sinica)Patrick M. Koch(Institute of Astronomy and Astrophysics, Academia Sinica)Shoko Koyama(Institute of Astronomy and Astrophysics, Academia Sinica)M. Krämer(Max Planck Institute for Radio Astronomy)C. Krämer(Institut de Radioastronomie Millimétrique)T. P. Krichbaum(Max Planck Institute for Radio Astronomy)Cheng‐Yu Kuo(National Sun Yat-sen University)Tod R. Lauer(Kitt Peak National Observatory)Sang-Sung Lee(Korea Astronomy and Space Science Institute)Yan-Rong Li(Chinese Academy of Sciences)Zhiyuan 志远 Li 李(Nanjing University)M. Lindqvist(Chalmers University of Technology)Kuo Liu(Max Planck Institute for Radio Astronomy)Elisabetta Liuzzo(Istituto di Radioastronomia di Bologna)Wen-Ping Lo(Institute of Astronomy and Astrophysics, Academia Sinica)A. P. Lobanov(Max Planck Institute for Radio Astronomy)Laurent Loinard(Universidad Nacional Autónoma de México)C. J. Lonsdale(Massachusetts Institute of Technology)Ru-Sen Lu(Shanghai Astronomical Observatory)Nicholas R. MacDonald(Max Planck Institute for Radio Astronomy)Jirong 基荣 Mao 毛(Chinese Academy of Sciences)Sera Markoff(University of Amsterdam)Daniel P. Marrone(University of Arizona)Alan P. Marscher(Boston University)I. Martí‐Vidal(Yebes Observatory)Satoki Matsushita(Institute of Astronomy and Astrophysics, Academia Sinica)Lynn D. Matthews(Massachusetts Institute of Technology)Lia Medeiros(University of Arizona)K. M. Menten(Max Planck Institute for Radio Astronomy)Yosuke Mizuno(Goethe University Frankfurt)Izumi Mizuno(East Asian Observatory)J. M. Moran(Woodwell Climate Research Center)Kotaro Moriyama(National Astronomical Observatory of Japan)Monika Mościbrodzka(Radboud University Nijmegen)Cornelia Müller(Radboud University Nijmegen)Hiroshi Nagai(The Graduate University for Advanced Studies, SOKENDAI)Neil M. Nagar(University of Concepción)Masanori Nakamura(Institute of Astronomy and Astrophysics, Academia Sinica)Ramesh Narayan(Woodwell Climate Research Center)Gopal Narayanan(University of Massachusetts Amherst)Iniyan Natarajan(Rhodes University)R. Neri(Institut de Radioastronomie Millimétrique)Chunchong Ni(University of Waterloo)A. Noutsos(Max Planck Institute for Radio Astronomy)Hiroki Okino(National Astronomical Observatory of Japan)Héctor Olivares(Goethe University Frankfurt)Gisela N. Ortiz-León(Max Planck Institute for Radio Astronomy)Tomoaki Oyama(National Astronomical Observatory of Japan)Feryal Özel(University of Arizona)Daniel C. M. Palumbo(Woodwell Climate Research Center)Nimesh Patel(Center for Astrophysics Harvard & Smithsonian)Ue‐Li Pen(Canadian Institute for Advanced Research)Dominic W. Pesce(Woodwell Climate Research Center)Vincent Piétu(Institut de Radioastronomie Millimétrique)R. L. Plambeck(University of California, Berkeley)Aleksandar PopStefanija(University of Massachusetts Amherst)Oliver Porth(Goethe University Frankfurt)Ben Prather(University of Illinois Urbana-Champaign)Jorge A. Preciado-López(Perimeter Institute)Dimitrios Psaltis(University of Arizona)Hung-Yi Pu(Perimeter Institute)Venkatessh Ramakrishnan(University of Concepción)Ramprasad RaoMark G. Rawlings(East Asian Observatory)Alexander W. Raymond(Woodwell Climate Research Center)Luciano Rezzolla(Goethe University Frankfurt)Bart Ripperda(Goethe University Frankfurt)Freek Roelofs(Radboud University Nijmegen)A. E. E. Rogers(Massachusetts Institute of Technology)E. Ros(Max Planck Institute for Radio Astronomy)Mel Rose(University of Arizona)Arash Roshanineshat(University of Arizona)Helge Rottmann(Max Planck Institute for Radio Astronomy)A. L. Roy(Max Planck Institute for Radio Astronomy)Chet Ruszczyk(Massachusetts Institute of Technology)Benjamin R. Ryan(Los Alamos National Laboratory)K. L. J. Rygl(Istituto di Radioastronomia di Bologna)Salvador Sánchez(Instituto de Radioastronomía Milimétrica)David Sánchez-Argüelles(National Institute of Astrophysics, Optics and Electronics)Mahito Sasada(Hiroshima University)T. Savolainen(Max Planck Institute for Radio Astronomy)F. Peter Schloerb(University of Massachusetts Amherst)K. Schüster(Institut de Radioastronomie Millimétrique)Lijing Shao(Peking University)Zhi-Qiang Shen(Chinese Academy of Sciences)Des Small(Joint Institute for VLBI ERIC)Bong Won Sohn(Yonsei University)Jason Soohoo(Massachusetts Institute of Technology)Fumie Tazaki(National Astronomical Observatory of Japan)Paul Tiede(University of Waterloo)R. P. J. Tilanus(Leiden University)Michael S. Titus(Massachusetts Institute of Technology)Kenji Toma(Tohoku University)Pablo Torné(Instituto de Radioastronomía Milimétrica)Tyler Trent(University of Arizona)Sascha Trippe(Seoul National University)Shuichiro Tsuda(National Astronomical Observatory of Japan)Ilse van Bemmel(Joint Institute for VLBI ERIC)Huib Jan van Langevelde(Leiden University)Daniel R. van Rossum(Radboud University Nijmegen)Jan Wagner(Max Planck Institute for Radio Astronomy)J. F. C. Wardle(Brandeis University)Jonathan Weintroub(Woodwell Climate Research Center)Norbert Wex(Max Planck Institute for Radio Astronomy)Robert Wharton(Max Planck Institute for Radio Astronomy)Maciek Wielgus(Woodwell Climate Research Center)George N. Wong(University of Illinois Urbana-Champaign)Qingwen 庆文 Wu 吴(Huazhong University of Science and Technology)André Young(Radboud University Nijmegen)Ken Young(Center for Astrophysics Harvard & Smithsonian)Ziri Younsi(Goethe University Frankfurt)Feng 峰 Yuan 袁(Shanghai Astronomical Observatory)Ye-Fei 业飞 Yuan 袁(University of Science and Technology of China)J. A. Zensus(Max Planck Institute for Radio Astronomy)Guang-Yao Zhao(Korea Astronomy and Space Science Institute)Shan-Shan Zhao(Radboud University Nijmegen)Ziyan Zhu(Harvard University)Juan Carlos Algaba(Institute of Astronomy and Astrophysics, Academia Sinica)Alexander Allardi(University of Vermont)Rodrigo Amestica(National Radio Astronomy Observatory)U. Bach(Max Planck Institute for Radio Astronomy)Christopher Beaudoin(Massachusetts Institute of Technology)B. A. Benson(Fermi National Accelerator Laboratory)Ryan Berthold(East Asian Observatory)J. Blanchard(University of Concepción)R. Blundell(Center for Astrophysics Harvard & Smithsonian)Sandra Bustamente(National Institute of Astrophysics, Optics and Electronics)R. J. Cappallo(Massachusetts Institute of Technology)Edgar Castillo-Domínguez(National Institute of Astrophysics, Optics and Electronics)Chih-Cheng Chang(Institute of Astronomy and Astrophysics, Academia Sinica)Shu-Hao Chang(Institute of Astronomy and Astrophysics, Academia Sinica)Song-Chu Chang(National Chung Shan Institute of Science and Technology)Chung-Chen Chen(Institute of Astronomy and Astrophysics, Academia Sinica)Ryan ChilsonTim C. Chuter(East Asian Observatory)Rodrigo Córdova Rosado(Woodwell Climate Research Center)I. M. Coulson(East Asian Observatory)T. M. Crawford(University of Chicago)Joseph CrowleyJohn David(Instituto de Radioastronomía Milimétrica)M. Derome(Massachusetts Institute of Technology)Matthew R. Dexter(University of California, Berkeley)Sven Dornbusch(Max Planck Institute for Radio Astronomy)Kevin A. DudevoirSergio A. Dzib(Max Planck Institute for Radio Astronomy)Chris Eckert(Massachusetts Institute of Technology)N. R. Erickson(University of Massachusetts Amherst)W. Everett(University of Colorado Boulder)Aaron Faber(Western University)Joseph Farah(Woodwell Climate Research Center)Vernon Fath(University of Massachusetts Amherst)Thomas W. Folkers(University of Arizona)David C. Forbes(University of Arizona)R. Freund(University of Arizona)Arturo I. Gómez-Ruiz(National Institute of Astrophysics, Optics and Electronics)David M. Gale(National Institute of Astrophysics, Optics and Electronics)F. Gao(Shanghai Astronomical Observatory)Gertie Geertsema(Royal Netherlands Meteorological Institute)D. A. Graham(Max Planck Institute for Radio Astronomy)Christopher H. Greer(University of Arizona)Ronald Grosslein(University of Massachusetts Amherst)Frédéric Gueth(Institut de Radioastronomie Millimétrique)N. W. Halverson(University of Colorado Boulder)Chih-Chiang Han(Institute of Astronomy and Astrophysics, Academia Sinica)Kuo-Chang Han(National Chung Shan Institute of Science and Technology)H. Jinchi(National Chung Shan Institute of Science and Technology)Yutaka Hasegawa(Osaka Prefecture University)J. W. Henning(Argonne National Laboratory)A. Hernández-Gómez(Centre National de la Recherche Scientifique)R. Herrero‐Illana(European Southern Observatory)S. Heyminck(Max Planck Institute for Radio Astronomy)Akihiko Hirota(Atacama Large Millimeter Submillimeter Array)James Hoge(East Asian Observatory)Yau-De Huang(Institute of Astronomy and Astrophysics, Academia Sinica)C. M. Violette Impellizzeri(National Radio Astronomy Observatory)Homin Jiang(Institute of Astronomy and Astrophysics, Academia Sinica)A. Kamble(Woodwell Climate Research Center)Ryan Keisler(University of Chicago)Kimihiro Kimura(Osaka Prefecture University)Yusuke Kono(National Astronomical Observatory of Japan)Derek Kubo(East Asian Observatory)John Kuroda(East Asian Observatory)Richard Lacasse(National Radio Astronomy Observatory)Robert A. Laing(SKA Observatory)E. M. Leitch(University of Chicago)Chao-Te Li(Institute of Astronomy and Astrophysics, Academia Sinica)L. C.-C. Lin(Institute of Astronomy and Astrophysics, Academia Sinica)Ching-Tang Liu(National Chung Shan Institute of Science and Technology)Kuan-Yu Liu(Institute of Astronomy and Astrophysics, Academia Sinica)Li-Ming Lu(National Chung Shan Institute of Science and Technology)R. G. Marson(National Radio Astronomy Observatory)Pierre Martin-Cocher(Institute of Astronomy and Astrophysics, Academia Sinica)Kyle Massingill(University of Arizona)Callie Matulonis(East Asian Observatory)Martin P. McColl(University of Arizona)Stephen R. McWhirter(Massachusetts Institute of Technology)Hugo Messias(Atacama Large Millimeter Submillimeter Array)Zheng Meyer-Zhao(Institute of Astronomy and Astrophysics, Academia Sinica)Daniel Michalik(University of Chicago)Alfredo Montaña(National Institute of Astrophysics, Optics and Electronics)William Montgomerie(East Asian Observatory)Matias Mora-Klein(National Radio Astronomy Observatory)D. Muders(Max Planck Institute for Radio Astronomy)Andrew Nadolski(University of Illinois Urbana-Champaign)S. Navarro(Instituto de Radioastronomía Milimétrica)Chi H. Nguyen(University of Arizona)Hiroaki Nishioka(Institute of Astronomy and Astrophysics, Academia Sinica)Timothy Norton(Center for Astrophysics Harvard & Smithsonian)George NystromHideo Ogawa(Osaka Prefecture University)Peter OshiroTomoaki Oyama(National Astronomical Observatory of Japan)S. Padin(University of Chicago)Harriet Parsons(East Asian Observatory)Scott Paine(Center for Astrophysics Harvard & Smithsonian)J. Peñalver(Instituto de Radioastronomía Milimétrica)N. Phillips(Atacama Large Millimeter Submillimeter Array)Michael Poirier(Massachusetts Institute of Technology)Nicolas Pradel(Institute of Astronomy and Astrophysics, Academia Sinica)Rurik A. Primiani(Systems and Technology Research (United States))Philippe RaffinA. Rahlin(Fermi National Accelerator Laboratory)George Reiland(University of Arizona)C. Risacher(Institut de Radioastronomie Millimétrique)Ignacio Ruiz(Instituto de Radioastronomía Milimétrica)Alejandro F. Sáez-Madaín(National Radio Astronomy Observatory)Remi Sassella(Institut de Radioastronomie Millimétrique)P. Schellart(Radboud University Nijmegen)Paul Shaw(Institute of Astronomy and Astrophysics, Academia Sinica)Kevin M. Silva(East Asian Observatory)Hotaka Shiokawa(Center for Astrophysics Harvard & Smithsonian)David R. Smith(Georgia Institute of Technology)W. M. SnowKamal Souccar(University of Massachusetts Amherst)Don Sousa(Massachusetts Institute of Technology)T. K. Sridharan(Center for Astrophysics Harvard & Smithsonian)Ranjani SrinivasanWilliam Stahm(East Asian Observatory)A. A. Stark(Center for Astrophysics Harvard & Smithsonian)Kyle Story(Kavli Institute for Particle Astrophysics and Cosmology)Sjoerd T. Timmer(Radboud University Nijmegen)Laura Vertatschitsch(Center for Astrophysics Harvard & Smithsonian)Craig Walther(East Asian Observatory)Ta-Shun Wei(Institute of Astronomy and Astrophysics, Academia Sinica)N. Whitehorn(University of California, Los Angeles)A. R. Whitney(Massachusetts Institute of Technology)D. P. Woody(California Institute of Technology)J. G. A. Wouterloot(East Asian Observatory)Melvin Wright(University of California, Berkeley)Paul Yamaguchi(Center for Astrophysics Harvard & Smithsonian)Chen-Yu Yu(Institute of Astronomy and Astrophysics, Academia Sinica)Milagros Zeballos(National Institute of Astrophysics, Optics and Electronics)L. M. Ziurys(University of Arizona)

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Abstract

Abstract The Event Horizon Telescope (EHT) is a very long baseline interferometry (VLBI) array that comprises millimeter- and submillimeter-wavelength telescopes separated by distances comparable to the diameter of the Earth. At a nominal operating wavelength of ∼1.3 mm, EHT angular resolution ( λ / D ) is ∼25 μ as, which is sufficient to resolve nearby supermassive black hole candidates on spatial and temporal scales that correspond to their event horizons. With this capability, the EHT scientific goals are to probe general relativistic effects in the strong-field regime and to study accretion and relativistic jet formation near the black hole boundary. In this Letter we describe the system design of the EHT, detail the technology and instrumentation that enable observations, and provide measures of its performance. Meeting the EHT science objectives has required several key developments that have facilitated the robust extension of the VLBI technique to EHT observing wavelengths and the production of instrumentation that can be deployed on a heterogeneous array of existing telescopes and facilities. To meet sensitivity requirements, high-bandwidth digital systems were developed that process data at rates of 64 gigabit s −1 , exceeding those of currently operating cm-wavelength VLBI arrays by more than an order of magnitude. Associated improvements include the development of phasing systems at array facilities, new receiver installation at several sites, and the deployment of hydrogen maser frequency standards to ensure coherent data capture across the array. These efforts led to the coordination and execution of the first Global EHT observations in 2017 April, and to event-horizon-scale imaging of the supermassive black hole candidate in M87.

Astrophysical Phenomena and Observations Astrophysics and Cosmic Phenomena Pulsars and Gravitational Waves ResearchVery-long-baseline interferometryPhysicsEvent horizonTelescopeHydrogen maserSupermassive black holeMillimeterInstrumentation (computer programming)Angular resolution (graph drawing)Maser

Funding

National Science Foundation
Smithsonian Institution
U.S. Department of Energy
National Aeronautics and Space Administration
John Templeton Foundation
Gordon and Betty Moore Foundation
Massachusetts Institute of Technology
Harvard University
University of Chicago
University of Arizona
Innovation, Science and Economic Development Canada
Compute Canada
Strong
Ministerio de Ciencia, Innovación y Universidades
National Radio Astronomy Observatory
Associated Universities
International Max Planck Research School for Environmental, Cellular and Molecular Microbiology
Government of Canada
Leverhulme Trust
European Commission
National Research Foundation
Department of Science and Technology, Ministry of Science and Technology, India
Ministry of Education, Culture, Sports, Science and Technology
Academia Sinica
Chinese Academy of Sciences
Consejo Nacional de Ciencia y Tecnología
Nederlandse Organisatie voor Wetenschappelijk Onderzoek
Ministerio de Economía y Competitividad
Generalitat Valenciana
Korea Astronomy and Space Science Institute
National Research Foundation of Korea
Max-Planck-Gesellschaft
Vetenskapsrådet
China Scholarship Council
European Southern Observatory
Centre National de la Recherche Scientifique
Universidad Nacional Autónoma de México
National Astronomical Observatory of Japan
Russian Science Foundation
Ministero dello Sviluppo Economico
Recruitment Program of Global Experts
Istituto Nazionale di Fisica Nucleare
Instituto de Astrofísica de Andalucía
Institut Périmètre de physique théorique
Toray Science Foundation
National Nuclear Security Administration
Natural Sciences and Engineering Research Council of Canada
Japan Society for the Promotion of Science
Comisión Nacional de Investigación Científica y Tecnológica
Dirección General de Asuntos del Personal Académico, Universidad Nacional Autónoma de México
National Institutes of Natural Sciences
Office of Polar Programs
Los Alamos National Laboratory