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

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 , 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 , 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 , Dominic O. Chang

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

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 A* data exhibit variability that exceeds what can be explained by the uncertainties in the data or by the effects of interstellar scattering. The magnitude of this variability can be a substantial fraction of the correlated flux density, reaching ~100% on some baselines. Through an exploration of simple geometric source models, we demonstrate that ring-like morphologies provide better fits to the Sgr A* data than do other morphologies with comparable complexity. We develop two strategies for fitting static geometric ring models to the time-variable Sgr A* data; one strategy fits models to short segments of data over which the source is static and averages these independent fits, while the other fits models to the full data set using a parametric model for the structural variability power spectrum around the average source structure. Both geometric modeling and image-domain feature extraction techniques determine the ring diameter to be 51.8 ± 2.3 μas (68% credible intervals), with the ring thickness constrained to have an FWHM between ~30% and 50% of the ring diameter. To bring the diameter measurements to a common physical scale, we calibrate them using synthetic data generated from GRMHD simulations. This calibration constrains the angular size of the gravitational radius to be ${4.8}_{-0.7}^{+1.4}$ μas, which we combine with an independent distance measurement from maser parallaxes to determine the mass of Sgr A* to be ${4.0}_{-0.6}^{+1.1}\times {10}^{6}$ M _⊙.

Mots clés: Black holes

Domaines: Planète et Univers [physics]; Astrophysique [astro-ph]

Kazunori Akiyama, Antxon Alberdi, Walter Alef, Juan Carlos Algaba, Richard Anantua, et al.. First Sagittarius A* Event Horizon Telescope Results. IV. Variability, Morphology, and Black Hole Mass. The Astrophysical journal letters, 2022, 930, ⟨10.3847/2041-8213/ac6736⟩. ⟨insu-03713314⟩