First Sagittarius A* Event Horizon Telescope Results. II. EHT and Multiwavelength Observations, Data Processing, and Calibration

@article{Collaboration2022FirstSA,
  title={First Sagittarius A* Event Horizon Telescope Results. II. EHT and Multiwavelength Observations, Data Processing, and Calibration},
  author={Event Horizon Telescope Collaboration and Kazunori Akiyama and Antxon Alberdi and Walter Alef and Juan Carlos Algaba and Richard Anantua and Keiichi Asada and Rebecca Azulay and Uwe Bach and Anne-Kathrin Baczko and David Ball and Mislav Balokovi{\'c} and John Barrett and Michi Baub{\"o}ck and Bradford A. Benson and Dan Bintley and Lindy L. Blackburn and Raymond Blundell and Katherine L. Bouman and Geoff C. Bower and Hope Boyce and Michael Bremer and Christiaan D. Brinkerink and Roger Brissenden and Silke Britzen and Avery E. Broderick and Dominique Broguiere and Thomas Bronzwaer and Sandra Bustamante and Do-young Byun and John E. Carlstrom and Chiara Ceccobello and Andrew Chael and Chi-kwan Chan and Koushik Chatterjee and Shami Chatterjee and Ming-Tang Chen and Yongjun 永 军 Chen 陈 and Xiaopeng Cheng and Ilje Cho and Pierre Christian and Nicholas S. Conroy and John E. Conway and James M. Cordes and Thomas M. Crawford and Geoffrey B. Crew and Alejandro Cruz-Osorio and Yuzhu 玉竹 Cui 崔 and Jordy Davelaar and Mariafelicia De Laurentis and Roger Deane and Jessica Dempsey and Gregory Desvignes and Jason Dexter and Vedant Dhruv and Sheperd S. Doeleman and Sean Dougal and Sergio A. Dzib and Ralph P. Eatough and Razieh Emami and Heino Falcke and Joseph R. Farah and Vincent L. Fish and Edward B. Fomalont and Heather A. Ford and Raquel Fraga-Encinas and William T. Freeman and Per Friberg and Christian M. Fromm and Antonio Fuentes 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 Arturo I. G{\'o}mez-Ruiz and Jos{\'e} L. G{\'o}mez and Minfeng 敏峰 Gu 顾 and Mark A. Gurwell and Kazuhiro Hada and Daryl Haggard and Kari Haworth and Michael H. Hecht and Ronald Hesper and Dirk Heumann and Luis C. 子山 Ho 何 and Paul T. P. Ho and Mareki Honma and Chih-Wei L. Huang and Lei 磊 Huang 黄 and David H. Hughes and Shiro Ikeda and C. M. Violette Impellizzeri and Makoto Inoue and Sara Issaoun and David J. James and Buell T. Jannuzi and Michael Janssen and Britton Jeter and Wu 悟 Jiang 江 and Alejandra Jim{\'e}nez-Rosales and Michael D. Johnson and Svetlana G. Jorstad and Abhishek V. Joshi and Taehyun Jung and Mansour Karami and Ramesh Karuppusamy and Tomohisa Kawashima and Garrett K. Keating and Mark Kettenis and Dong-Jin Kim and Jae-Young Kim and Jongsoo Kim and Junhan Kim and Motoki Kino and Jun Yi Koay and Prashant Kocherlakota and Yutaro Kofuji and Patrick M. Koch and Shoko Koyama and Carsten Kramer and Michael Kramer and Thomas P. Krichbaum and C. Y. Kuo and Noemi La Bella and Tod R. Lauer and Daeyoung Lee and Sang-Sung Lee and Po Kin Leung and Aviad Levis and Zhiyuan 志远 Li 李 and Rocco Lico and Greg Lindahl and Michael Lindqvist and Mikhail M. Lisakov and Jun 俊 Liu 刘 and Kuo Liu and Elisabetta Liuzzo and Wen-Ping Lo and Andrei P. Lobanov and Laurent Loinard and Colin J. Lonsdale and Ru-Sen 如森 Lu 路 and Jirong 基荣 Mao 毛 and Nicola Marchili 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 Daniel Michalik and Izumi Mizuno and Yosuke Mizuno and James M. Moran and Kotaro Moriyama and Monika Mościbrodzka and Cornelia M{\"u}ller and Alejandro Mus and Gibwa Musoke and Ioannis Myserlis and Andrew Nadolski and Hiroshi Nagai and Neil M. Nagar and Masanori Nakamura and Ramesh Narayan and Gopal Narayanan and Iniyan Natarajan and Antonios Nathanail and Santiago Navarro Fuentes and Joey Neilsen and Roberto Neri and Chunchong Ni and Aristeidis Noutsos and Michael A. Nowak and Junghwan Oh and Hiroki Okino and H{\'e}ctor Olivares and Gisela N. Ortiz-L{\'e}on and Tomoaki Oyama and Feryal {\"O}zel and Daniel C. M. Palumbo and Georgios Filippos Paraschos and Jongho Park and Harriet Parsons and Nimesh 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 Felix M. P{\"o}tzl 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 Angelo Ricarte and Bart Ripperda and Freek Roelofs and Alan E. E. Rogers and Eduardo Ros and Cristina Romero-Ca{\~n}izales and Arash Roshanineshat and Helge Rottmann and Alan L. Roy and Ignacio Ruiz and Chester A. Ruszczyk and Kazi L. J. Rygl and Salvador S{\'a}nchez and David S{\'a}nchez-Arg{\"u}elles and Miguel S{\'a}nchez-Portal and Mahito Sasada and Kaushik Satapathy and Tuomas Savolainen and F. P. Schloerb and Jonathan Schonfeld and Karl F. Schuster and Lijing Shao and Zhiqiang 志强 Shen 沈 and Des Small and Bong Won Sohn and Jason SooHoo and Kamal Souccar and He 赫 Sun 孙 and Fumie Tazaki and Alexandra J. Tetarenko and Paul Tiede and Remo P. J. Tilanus and Michael Titus and Pablo Torne and Efthalia Traianou and Tyler Trent and Sascha Trippe and Matthew A. Turk and I. M. van Bemmel and Huib Jan van Langevelde and Daniel R. van Rossum and Jesse Vos and Jan Wagner and Derek Ward-Thompson and J. F. C. Wardle and Jonathan Weintroub and Norbert Wex and Robert S. Wharton and Maciek Wielgus and Kaj Wiik and Gunther Witzel and Michael F. Wondrak and George N. Wong and Qingwen 庆文 Wu 吴 and Paul Yamaguchi and Doosoo Yoon and Andr{\'e} Young and K. H. Young and Ziri Younsi and Feng 峰 Yuan 袁 and Ye-Fei 业 飞 Yuan 袁 and J. Anton Zensus and Shuo Zhang and Guangyao Zhao and Shan-Shan 杉杉 Zhao 赵 and Claudio Agurto and Juan Pablo Araneda and Oriel Arriagada and Alessandra Bertarini and Ryan M. Berthold and Jay Blanchard and Kent Masterson Brown and Mauricio C{\'a}rdenas and Michael Cantzler and Patricio Caro and Timothy C. Chuter and Mirosław Ciechanowicz and Iain M. Coulson and Joseph W. Crowley and Nathalie Degenaar and Sven Dornbusch and Carlos A. Dur{\'a}n and Karl Forster and Gertie Geertsema and Edouard Gonz{\'a}lez and Dave Graham and Fr'ed'eric Gueth and Chih-Chiang Han and Cristian Herrera and Rub{\'e}n Herrero-Illana and Stefan Heyminck and James Hoge and Yau-De Ted Huang and Homin Jiang and David John and Thomas Klein and Derek Y. Kubo and John Kuroda and Caleb Kwon and Robert Laing and Ching Tang Liu and Kuan-Yu Liu and Felipe Mac-Auliffe and Pierre L. Martin-Cocher and Callie Matulonis and Hugo Messias and Z. Meyer-Zhao and Francisco Montenegro-Montes and William Montgomerie and Dirk Muders and Hiroaki Nishioka and Timothy J. Norton and Rodrigo Olivares and J-P Perez-Beaupuits and Rodrigo Parra and Michael Poirier and Nicolas Pradel and Philippe Raffin and Jorge Ram{\'i}rez and Mark T. Reynolds and Alejandro F. Saez-Madain and Jorge Santana and Kevin M. Silva and Don Sousa and William Stahm and Karl J. E. Torstensson and Paulina Venegas and Craig A. Walther and Gundolf Wieching and Rudy Wijnands and Jan G. A. Wouterloot},
  journal={The Astrophysical Journal Letters},
  year={2022},
  volume={930}
}
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 campaign. The observations were carried out with eight facilities at six locations across the globe. Novel calibration methods are employed to account for Sgr A*'s flux variability. The majority of the 1.3 mm emission arises from horizon scales, where intrinsic structural source variability is… 
37 Citations

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References

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First Sagittarius A* Event Horizon Telescope Results. III. Imaging of the Galactic Center Supermassive Black Hole

We present the first event-horizon-scale images and spatiotemporal analysis of Sgr A* taken with the Event Horizon Telescope in 2017 April at a wavelength of 1.3 mm. Imaging of Sgr A* has been

First Sagittarius A* Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole in the Center of the Milky Way

We present the first Event Horizon Telescope (EHT) observations of Sagittarius A* (Sgr A*), the Galactic center source associated with a supermassive black hole. These observations were conducted in

Millimeter Light Curves of Sagittarius A* Observed during the 2017 Event Horizon Telescope Campaign

The Event Horizon Telescope (EHT) observed the compact radio source, Sagittarius A* (Sgr A*), in the Galactic Center on 2017 April 5–11 in the 1.3 mm wavelength band. At the same time,

First Sagittarius A* Event Horizon Telescope Results. IV. Variability, Morphology, and Black Hole Mass

In this paper we quantify the temporal variability and image morphology of the horizon-scale emission from Sgr A*, as observed by the EHT in 2017 April at a wavelength of 1.3 mm. We find that the Sgr

First Sagittarius A* Event Horizon Telescope Results. V. Testing Astrophysical Models of the Galactic Center Black Hole

In this paper we provide a first physical interpretation for the Event Horizon Telescope's (EHT) 2017 observations of Sgr A*. Our main approach is to compare resolved EHT data at 230 GHz and

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

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

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Context. Radio and mm-wavelength observations of Sagittarius A* (Sgr A*), the radio source associated with the supermassive black hole at the center of our Galaxy, show that it behaves as a partially

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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

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We report the results from recent observations of Sgr A* at short-/submillimeter wavelengths made with the partially finished Submillimeter Array (SMA) on Mauna Kea. A total of 25 epochs of
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