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

  title={First M87 Event Horizon Telescope Results. II. Array and Instrumentation},
  author={Kazunori Akiyama and Antxon Alberdi and Walter Alef and Keiichi Asada and Rebecca Azulay and Anne-Kathrin Baczko and David Ball and Mislav Balokovi{\'c} and John Barrett and Dan Bintley and Lindy L. Blackburn and Wilfred Boland and Katherine L. Bouman and Geoffrey C. Bower and Michael Bremer and Christiaan D. Brinkerink and Roger Brissenden and Silke Britzen and Avery E. Broderick and Dominique Broguiere and Thomas Bronzwaer and Do-young Byun and John E. Carlstrom and Andrew Chael and Chi-kwan Chan and Shami Chatterjee and Koushik Chatterjee and Ming-Tang Chen and Yongjun Chen and Ilje Cho and Pierre Christian and John Conway and James M. Cordes and Geoffrey B. Crew and Yuzhu Cui and Jordy Davelaar and Mariafelicia De Laurentis and Roger Deane and Jessica Dempsey and Gregory Desvignes and Jason Dexter and Sheperd S. Doeleman and Ralph P. Eatough and Heino Falcke and Vincent L. Fish and Edward B. Fomalont and Raquel Fraga-Encinas and Per Friberg and Christian M. Fromm and Jos{\'e} L. G{\'o}mez and Peter Galison and Charles F. Gammie and Roberto Garc{\'i}a and Olivier Gentaz and Boris Georgiev and Ciriaco Goddi and Roman Gold and Minfeng Gu and Mark A. Gurwell and Kazuhiro Hada and Michael H. Hecht and Ronald Hesper and Luis C. Ho and Paul T. P. Ho and Mareki Honma and Chih-Wei L. Huang and Lei Huang and David H. Hughes and Shiro Ikeda and Makoto Inoue and Sara Issaoun and David J. James and Buell T. Jannuzi and Michael Janssen and Britton Jeter and Wu Jiang and Michael D. Johnson and Svetlana G. Jorstad and Taehyun Jung and Mansour Karami and Ramesh Karuppusamy and Tomohisa Kawashima and Garrett K. Keating and Mark Kettenis and Jae-Young Kim and Junhan Kim and Jongsoo Kim and Motoki Kino and Jun Yi Koay and Patrick M. Koch and Shoko Koyama and Michael Kramer and Carsten Kramer and Thomas P. Krichbaum and C. Y. Kuo and Tod R. Lauer and Sang-Sung Lee and Yan-Rong Li and Zhiyuan Li and Michael Lindqvist and Kuo Liu and Elisabetta Liuzzo and W. Lo and Andrei P. Lobanov and Laurent Loinard and Colin J. Lonsdale and Ru-Sen Lu and Nicholas R. MacDonald and Jirong Mao and Sera B. Markoff and Daniel P. Marrone and Alan P. Marscher and Iv{\'a}n Mart{\'i}-Vidal and Satoki Matsushita and Lynn D. Matthews and Lia Medeiros and Karl M. Menten and Yosuke Mizuno and Izumi Mizuno and James M. Moran and Kotaro Moriyama and Monika A. Mościbrodzka and Cornelia M{\"u}ller and Hiroshi Nagai and Neil M. Nagar and Masanori Nakamura and Ramesh Narayan and Gopal Narayanan and Iniyan Natarajan and Roberto Neri and Chunchong Ni and Aristeidis Noutsos and Hiroki Okino and H{\'e}ctor Olivares and Gisela N. Ortiz-L{\'e}on and Tomoaki Oyama and F. Ozel and Daniel C. M. Palumbo and Nimesh A. Patel and Ue-li Pen and Dominic W. Pesce and Vincent Pi{\'e}tu and Richard L. Plambeck and Aleksandar PopStefanija and Oliver Porth and Ben S. Prather and Jorge A. Preciado-L{\'o}pez and Dimitrios Psaltis and Hung-Yi Pu and Venkatessh Ramakrishnan and Ramprasad Rao and Mark G. Rawlings and Alexander W. Raymond and Luciano Rezzolla and Bart Ripperda and Freek Roelofs and Alan E. E. Rogers and Eduardo Ros and Mel Rose and Arash Roshanineshat and Helge Rottmann and Alan L. Roy and Chester A. Ruszczyk and Benjamin R. Ryan and Kazi L. J. Rygl and Salvador S{\'a}nchez and David S{\'a}nchez-Arguelles and Mahito Sasada and Tuomas Savolainen and F. P. Schloerb and Karl F. Schuster and Lijing Shao and Zhi-qiang Shen and Des Small and Bong Won Sohn and Jason SooHoo and Fumie Tazaki and Paul Tiede and Remo P. J. Tilanus and Michael Titus and Kenji Toma and Pablo Torne and Tyler Trent and Sascha Trippe and Shuichi Tsuda and Ilse van Bemmel and Huib Jan van Langevelde and Daniel R. van Rossum and Jan Wagner and J. F. C. Wardle and Jonathan Weintroub and Norbert Wex and Robert S. Wharton and Maciek Wielgus and George N. Wong and Qingwen Wu and Andr{\'e} Young and K. H. Young and Ziri Younsi and Fenge Yuan and Ye-Fei Yuan and J. Anton Zensus and Guangyao Zhao and Shan-Shan Zhao and Ziyan Zhu and Juan Carlos Algaba and Alexander Allardi and Rodrigo Amestica and Uwe Bach and Christopher Beaudoin and Bradford A. Benson and Ryan M. Berthold and Jay Blanchard and Raymond Blundell and Sandra Bustamente and Roger J. Cappallo and E. Castillo-Dominguez and Chih-Cheng Chang and Shu-Hao Chang and Song-Chu Chang and Chung-Chen Chen and Ryan Chilson and Timothy C. Chuter and Rodrigo C{\'o}rdova Rosado and Iain M. Coulson and Thomas M. Crawford and Joseph W. Crowley and John David and Mark Derome and Matt Dexter and Sven Dornbusch and Kevin A. Dudevoir and Sergio A. Dzib and Chris Eckert and Neal Erickson and Wendeline B. Everett and Aaron Faber and Joseph R. Farah and Vernon Fath and Thomas W. Folkers and David C. Forbes and Robert W. Freund and Arturo I. G{\'o}mez-Ruiz and David Michel Gale and Feng Gao and Gertie Geertsema and David A. Graham and Christopher H. Greer and Ronald Grosslein and Fr'ed'eric Gueth and Nils W. Halverson and Chih-Chiang Han and Kuo-Chang Han and Jinchi Hao and Yutaka Hasegawa and Jason W. Henning and Antonio Hern{\'a}ndez-G{\'o}mez and Rub{\'e}n Herrero-Illana and Stefan Heyminck and Akihiko Hirota and James Hoge and Yau-De Ted Huang and C. M. Violette Impellizzeri and Homin Jiang and Atish Kamble and Ryan Keisler and Kimihiro Kimura and Yusuke Kono and Derek Y. Kubo and John Kuroda and Richard J. Lacasse and Robert Laing and Erik M. Leitch and Chao-Te Li and Lupin Chun-Che Lin and Ching Tang Liu and Kuan-Yu Liu and Li-Ming Lu and Ralph G. Marson and Pierre L. Martin-Cocher and Kyle D. Massingill and Callie Matulonis and Martin P. McColl and Stephen R. McWhirter and Hugo Messias and Z. Meyer-Zhao and Daniel Michalik and Alfredo Monta{\~n}a and William Montgomerie and Matias Mora-Klein and Dirk Muders and Andrew Nadolski and Santiago Navarro and Chi H. Nguyen and Hiroaki Nishioka and Timothy J. Norton and George U. Nystrom and Hideo Ogawa and Peter Oshiro and Stephen Padin and Harriet Parsons and Scott N. Paine and Juan Pe{\~n}alver and Neil M. Phillips and Michael Poirier and Nicolas Pradel and Rurik A. Primiani and Philippe Raffin and Alexandra S. Rahlin and George P. Reiland and Christophe Risacher and Ignacio Ruiz and Alejandro F. Saez-Madain and Remi Sassella and Pim Schellart and Paul Shaw and Kevin M. Silva and Hotaka Shiokawa and David R. Smith and William Parker Snow and Kamal Souccar and Don Sousa and Sridharan T. K. and Ranjani Srinivasan and William Stahm and Antony A. Stark and K. T. Story and Sjoerd T. Timmer and Laura Vertatschitsch and Craig A. Walther and Tashun Wei and Nathan Whitehorn and Alan R. Whitney and David P. Woody and Jan G. A. Wouterloot and Melvyn C. H. Wright and Paul Yamaguchi and Chen-Yu Yu and Milagros Zeballos and Lucy M Ziurys},
  journal={The Astrophysical Journal Letters},
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 μas, 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… 

First M87 Event Horizon Telescope Results. III. Data Processing and Calibration

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High resolution imaging of supermassive black holes shadows is a direct way to verify the theory of general relativity at extreme gravity conditions. Very Long Baseline Interferometry (VLBI)

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We present Event Horizon Telescope (EHT) 1.3 mm measurements of the radio source located at the position of the supermassive black hole Sagittarius A* (Sgr A*), collected during the 2017 April 5–11

Millimeter/Submillimeter VLBI with a Next Generation Large Radio Telescope in the Atacama Desert

The proposed next generation Event Horizon Telescope (ngEHT) concept envisions the imaging of various astronomical sources on scales of microarcseconds in unprecedented detail with at least two

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We present the results from a full polarization study carried out with the Atacama Large Millimeter/submillimeter Array (ALMA) during the first Very Long Baseline Interferometry (VLBI) campaign,

First M87 Event Horizon Telescope Results. VIII. Magnetic Field Structure near The Event Horizon

Event Horizon Telescope (EHT) observations at 230 GHz have now imaged polarized emission around the supermassive black hole in M87 on event-horizon scales. This polarized synchrotron radiation probes

First M87 Event Horizon Telescope Results. VII. Polarization of the Ring

In 2017 April, the Event Horizon Telescope (EHT) observed the near-horizon region around the supermassive black hole at the core of the M87 galaxy. These 1.3 mm wavelength observations revealed a

Event Horizon Telescope observations of the jet launching and collimation in Centaurus A

Very-long-baseline interferometry (VLBI) observations of active galactic nuclei at millimetre wavelengths have the power to reveal the launching and initial collimation region of extragalactic radio



First M87 Event Horizon Telescope Results. III. Data Processing and Calibration

We present the calibration and reduction of Event Horizon Telescope (EHT) 1.3 mm radio wavelength observations of the supermassive black hole candidate at the center of the radio galaxy M87 and the

The Event Horizon Telescope: exploring strong gravity and accretion physics

The Event Horizon Telescope (EHT), a global sub-millimeter wavelength very long baseline interferometry array, is now resolving the innermost regions around the supermassive black holes Sgr A* and

A VLBI receiving system for the South Pole Telescope

The Event Horizon Telescope (EHT) is a very-long-baseline interferometry (VLBI) experiment that aims to observe supermassive black holes with an angular resolution that is comparable to the event


The Event Horizon Telescope (EHT) is a project to assemble a Very Long Baseline Interferometry (VLBI) network of millimeter wavelength dishes that can resolve strong field general relativistic

First M87 Event Horizon Telescope Results. V. Physical Origin of the Asymmetric Ring

The Event Horizon Telescope (EHT) has mapped the central compact radio source of the elliptical galaxy M87 at 1.3 mm with unprecedented angular resolution. Here we consider the physical implications

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When surrounded by a transparent emission region, black holes are expected to reveal a dark shadow caused by gravitational light bending and photon capture at the event horizon. To image and study

First M87 Event Horizon Telescope Results. IV. Imaging the Central Supermassive Black Hole

We present the first Event Horizon Telescope (EHT) images of M87, using observations from April 2017 at 1.3 mm wavelength. These images show a prominent ring with a diameter of ∼40 μas, consistent

Radio observations of active galactic nuclei with mm-VLBI

Over the past few decades, our knowledge of jets produced by active galactic nuclei (AGN) has greatly progressed thanks to the development of very-long-baseline interferometry (VLBI). Nevertheless,

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We report results from very long baseline interferometric (VLBI) observations of the supermassive black hole in the Galactic center, Sgr A*, at 1.3 mm (230 GHz). The observations were performed in

R2DBE: A Wideband Digital Backend for the Event Horizon Telescope

The Event Horizon Telescope (EHT) is an earth-size aperture synthesis radio astronomy array capable of making high-resolution measurements of submillimeter emission near the event horizon of