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

Kazunori Akiyama , Antxon Alberdi , Walter Alef , Juan Carlos Algaba , Richard Anantua , Keiichi Asada , Rebecca Azulay , Uwe Bach , Anne-Kathrin Baczko , David Ball , Mislav Baloković , John Barrett , Michi Bauböck , Bradford A. Benson , Dan Bintley , Lindy Blackburn , Raymond Blundell , Katherine L. Bouman , Geoffrey C. Bower , Hope Boyce , Michael Bremer , Christiaan D. Brinkerink , Roger Brissenden , Silke Britzen , Avery E. Broderick , Dominique Broguiere , Thomas Bronzwaer , Sandra Bustamante , Do-Young Byun , John E. Carlstrom , Chiara Ceccobello , Andrew Chael , Chi-Kwan Chan , Koushik Chatterjee , Shami Chatterjee , Ming-Tang Chen , Yongjun Chen , Xiaopeng Cheng , Ilje Cho , Pierre Christian , Nicholas S. Conroy , John E. Conway , James M. Cordes , Thomas M. Crawford , Geoffrey B. Crew , Alejandro Cruz-Osorio , Yuzhu Cui , Jordy Davelaar , Mariafelicia de Laurentis , Roger Deane , Jessica Dempsey , Gregory Desvignes (1) , Jason Dexter , Vedant Dhruv , Sheperd S. Doeleman , Sean Dougal , Sergio A. Dzib , Ralph P. Eatough , Razieh Emami , Heino Falcke , Joseph Farah , Vincent L. Fish , Ed Fomalont , H. Alyson Ford , Raquel Fraga-Encinas , William T. Freeman , Per Friberg , Christian M. Fromm , Antonio Fuentes , Peter Galison , Charles F. Gammie , Roberto García , Olivier Gentaz , Boris Georgiev , Ciriaco Goddi , Roman Gold , Arturo I. Gómez-Ruiz , José L. Gómez , Minfeng Gu , Mark Gurwell , Kazuhiro Hada , Daryl Haggard , Kari Haworth , Michael H. Hecht , Ronald Hesper , Dirk Heumann , Luis C. Ho , Paul Ho , Mareki Honma , Chih-Wei L. Huang , Lei Huang , David H. Hughes , Shiro Ikeda , C. M. Violette Impellizzeri , Makoto Inoue , Sara Issaoun , David J. James , Buell T. Jannuzi , Michael Janssen , Britton Jeter , Wu Jiang , Alejandra Jiménez-Rosales , Michael D. Johnson , Svetlana Jorstad , Abhishek V. Joshi , Taehyun Jung , Mansour Karami , Ramesh Karuppusamy , Tomohisa Kawashima , Garrett K. Keating , Mark Kettenis , Dong-Jin Kim , Jae-Young Kim , Jongsoo Kim , Junhan Kim , Motoki Kino , Jun Yi Koay , Prashant Kocherlakota , Yutaro Kofuji , Patrick M. Koch , Shoko Koyama , Carsten Kramer , Michael Kramer , Thomas P. Krichbaum , Cheng-Yu Kuo , Noemi La Bella , Tod R. Lauer , Daeyoung Lee , Sang-Sung Lee , Po Kin Leung , Aviad Levis , Zhiyuan Li , Rocco Lico , Greg Lindahl , Michael Lindqvist , Mikhail Lisakov , Jun Liu , Kuo Liu , Elisabetta Liuzzo , Wen-Ping Lo , Andrei P. Lobanov , Laurent Loinard , Colin J. Lonsdale , Ru-Sen Lu , Jirong Mao , Nicola Marchili , Sera Markoff , Daniel P. Marrone , Alan P. Marscher , Iván Martí-Vidal , Satoki Matsushita , Lynn D. Matthews , Lia Medeiros , Karl M. Menten , Daniel Michalik , Izumi Mizuno , Yosuke Mizuno , James M. Moran , Kotaro Moriyama , Monika Moscibrodzka , Cornelia Müller , Alejandro Mus , Gibwa Musoke , Ioannis Myserlis , Andrew Nadolski , Hiroshi Nagai , Neil M. Nagar , Masanori Nakamura , Ramesh Narayan , Gopal Narayanan , Iniyan Natarajan , Antonios Nathanail , Santiago Navarro Fuentes , Joey Neilsen , Roberto Neri , Chunchong Ni , Aristeidis Noutsos , Michael A. Nowak , Junghwan Oh , Hiroki Okino , Héctor Olivares , Gisela N. Ortiz-León , Tomoaki Oyama , Feryal Özel , Daniel C. M. Palumbo , Georgios Filippos Paraschos , Jongho Park , Harriet Parsons , Nimesh Patel , Ue-Li Pen , Dominic W. Pesce , Vincent Piétu , Richard Plambeck , Aleksandar Popstefanija , Oliver Porth , Felix M. Pötzl , Ben Prather , Jorge A. Preciado-López , Dimitrios Psaltis , Hung-Yi Pu , Venkatessh Ramakrishnan , Ramprasad Rao , Mark G. Rawlings , Alexander W. Raymond , Luciano Rezzolla , Angelo Ricarte , Bart Ripperda , Freek Roelofs , Alan Rogers , Eduardo Ros , Cristina Romero-Cañizales , Arash Roshanineshat , Helge Rottmann , Alan L. Roy , Ignacio Ruiz , Chet Ruszczyk , Kazi L. J. Rygl , Salvador Sánchez , David Sánchez-Argüelles , Miguel Sánchez-Portal , Mahito Sasada , Kaushik Satapathy , Tuomas Savolainen , F. Peter Schloerb , Jonathan Schonfeld , Karl-Friedrich Schuster , Lijing Shao , Zhiqiang Shen , Des Small , Bong Won Sohn , Jason Soohoo , Kamal Souccar , He Sun , Fumie Tazaki , Alexandra J. Tetarenko , Paul Tiede , Remo P. J. Tilanus , Michael Titus , Pablo Torne , Efthalia Traianou , Tyler Trent , Sascha Trippe , Matthew Turk , Ilse van Bemmel , Huib Jan van Langevelde , Daniel R. van Rossum , Jesse Vos , Jan Wagner , Derek Ward-Thompson , John Wardle , Jonathan Weintroub , Norbert Wex , Robert Wharton , Maciek Wielgus , Kaj Wiik , Gunther Witzel , Michael F. Wondrak , George N. Wong , Qingwen Wu , Paul Yamaguchi , Doosoo Yoon , André Young , Ken Young , Ziri Younsi , Feng Yuan , Ye-Fei Yuan , J. Anton Zensus , Shuo Zhang , Guang-Yao Zhao , Shan-Shan Zhao , Claudio Agurto , Alexander Allardi , Rodrigo Amestica , Juan Pablo Araneda , Oriel Arriagada , Jennie L. Berghuis , Alessandra Bertarini , Ryan Berthold , Jay Blanchard , Ken Brown , Mauricio Cárdenas , Michael Cantzler , Patricio Caro , Edgar Castillo-Domínguez , Tin Lok Chan , Chih-Cheng Chang , Dominic O. Chang , Shu-Hao Chang , Song-Chu Chang , Chung-Chen Chen , Ryan Chilson , Tim C. Chuter , Miroslaw Ciechanowicz , Edgar Colin-Beltran , Iain M. Coulson , Joseph Crowley , Nathalie Degenaar , Sven Dornbusch , Carlos A. Durán , Wendeline B. Everett , Aaron Faber , Karl Forster , Miriam M. Fuchs , David M. Gale , Gertie Geertsema , Edouard González , Dave Graham , Frédéric Gueth , Nils W. Halverson , Chih-Chiang Han , Kuo-Chang Han , Yutaka Hasegawa , José Luis Hernández-Rebollar , Cristian Herrera , Ruben Herrero-Illana , Stefan Heyminck , Akihiko Hirota , James Hoge , Shelbi R. Hostler Schimpf , Ryan E. Howie , Yau-De Huang , Homin Jiang , Hao Jinchi , David John , Kimihiro Kimura , Thomas Klein , Derek Kubo , John Kuroda , Caleb Kwon , Richard Lacasse , Robert Laing , Erik M. Leitch , Chao-Te Li , Ching-Tang Liu , Kuan-Yu Liu , Lupin C. -C. Lin , Li-Ming Lu , Felipe Mac-Auliffe , Pierre Martin-Cocher , Callie Matulonis , John K. Maute , Hugo Messias , Zheng Meyer-Zhao , Alfredo Montaña , Francisco Montenegro-Montes , William Montgomerie , Marcos Emir Moreno Nolasco , Dirk Muders , Hiroaki Nishioka , Timothy J. Norton , George Nystrom , Hideo Ogawa , Rodrigo Olivares , Peter Oshiro , Juan Pablo Pérez-Beaupuits , Rodrigo Parra , Neil M. Phillips , Michael Poirier , Nicolas Pradel , Richard Qiu , Philippe A. Raffin , Alexandra S. Rahlin , Jorge Ramírez , Sean Ressler , Mark Reynolds , Iván Rodríguez-Montoya , Alejandro F. Saez-Madain , Jorge Santana , Paul Shaw , Leslie E. Shirkey , Kevin M. Silva , William Snow , Don Sousa , T. K. Sridharan , William Stahm , Anthony A. Stark , John Test , Karl Torstensson , Paulina Venegas , Craig Walther , Ta-Shun Wei , Chris White , Gundolf Wieching , Rudy Wijnands , Jan G. A. Wouterloot , Chen-Yu Yu , Wei Yu , Milagros Zeballos

1 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics

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 2017 using a global interferometric array of eight telescopes operating at a wavelength of λ = 1.3 mm. The EHT data resolve a compact emission region with intrahour variability. A variety of imaging and modeling analyses all support an image that is dominated by a bright, thick ring with a diameter of 51.8 ± 2.3 μas (68% credible interval). The ring has modest azimuthal brightness asymmetry and a comparatively dim interior. Using a large suite of numerical simulations, we demonstrate that the EHT images of Sgr A* are consistent with the expected appearance of a Kerr black hole with mass ~4 × 10⁶ M _⊙, which is inferred to exist at this location based on previous infrared observations of individual stellar orbits, as well as maser proper-motion studies. Our model comparisons disfavor scenarios where the black hole is viewed at high inclination (i > 50°), as well as nonspinning black holes and those with retrograde accretion disks. Our results provide direct evidence for the presence of a supermassive black hole at the center of the Milky Way, and for the first time we connect the predictions from dynamical measurements of stellar orbits on scales of 10³-10⁵ gravitational radii to event-horizon-scale images and variability. Furthermore, a comparison with the EHT results for the supermassive black hole M87* shows consistency with the predictions of general relativity spanning over three orders of magnitude in central mass.

Keywords: Black holes; Kerr black holes; Rotating black holes; Heterodyne interferometry; Galactic center

Domains: Sciences of the Universe [physics]; Astrophysics [astro-ph]

Kazunori Akiyama, Antxon Alberdi, Walter Alef, Juan Carlos Algaba, Richard Anantua, et al.. First Sagittarius A* Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole in the Center of the Milky Way. The Astrophysical Journal Letters, 2022, 930, ⟨10.3847/2041-8213/ac6674⟩. ⟨insu-03713319⟩