First Sagittarius A* Event Horizon Telescope Results. VI. Testing the Black Hole Metric
Journal article, 2022
Astrophysical black holes are expected to be described by the Kerr metric. This is the only stationary, vacuum, axisymmetric metric, without electromagnetic charge, that satisfies Einstein's equations and does not have pathologies outside of the event horizon. We present new constraints on potential deviations from the Kerr prediction based on 2017 EHT observations of Sagittarius A* (Sgr A*). We calibrate the relationship between the geometrically defined black hole shadow and the observed size of the ring-like images using a library that includes both Kerr and non-Kerr simulations. We use the exquisite prior constraints on the mass-to-distance ratio for Sgr A* to show that the observed image size is within similar to 10% of the Kerr predictions. We use these bounds to constrain metrics that are parametrically different from Kerr, as well as the charges of several known spacetimes. To consider alternatives to the presence of an event horizon, we explore the possibility that Sgr A* is a compact object with a surface that either absorbs and thermally reemits incident radiation or partially reflects it. Using the observed image size and the broadband spectrum of Sgr A*, we conclude that a thermal surface can be ruled out and a fully reflective one is unlikely. We compare our results to the broader landscape of gravitational tests. Together with the bounds found for stellar-mass black holes and the M87 black hole, our observations provide further support that the external spacetimes of all black holes are described by the Kerr metric, independent of their mass.
Author
Kazunori Akiyama
Antxon Alberdi
Walter Alef
Juan Carlos Algaba
Richard Anantua
Keiichi Asada
Rebecca Azulay
Uwe Bach
Anne-Kathrin Baczko
David Ball
Mislav Balokovic
John Barrett
Michi Baubock
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 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
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 Garcia
Olivier Gentaz
Boris Georgiev
Ciriaco Goddi
Roman Gold
Gomez-Ruiz
Jose L. Gomez
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 Jimenez-Rosales
Michael D. Johnson
Svetlana Jorstad
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
Ivan Marti-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 Muller
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
Joseph Neilsen
Roberto Neri
Chunchong Ni
Aristeidis Noutsos
Michael A. Nowak
Junghwan Oh
Hiroki Okino
Hector Olivares
Gisela N. Ortiz-Leon
Tomoaki Oyama
Feryal Ozel
Daniel C. M. Palumbo
Georgios Filippos Paraschos
Jongho Park
Harriet Parsons
Nimesh Patel
Ue-Li Pen
Dominic W. Pesce
Vincent Pietu
Richard Plambeck
Aleksandar PopStefanija
Oliver Porth
Felix M. Potzl
Ben Prather
Jorge A. Preciado-Lopez
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-Canizales
Arash Roshanineshat
Helge Rottmann
Alan L. Roy
Ignacio Ruiz
Chet Ruszczyk
Kazi L. J. Rygl
Salvador Sanchez
David Sanchez-Arguelles
Miguel Sanchez-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
Andre Young
Ken Young
Ziri Younsi
Feng Yuan
Ye-Fei Yuan
J. Anton Zensus
Shuo Zhang
Guang-Yao Zhao
Shan-Shan Zhao
Astrophysical Journal Letters
2041-8205 (ISSN) 2041-8213 (eISSN)
Vol. 930 2 L17Subject Categories (SSIF 2011)
Astronomy, Astrophysics and Cosmology
Other Physics Topics
Radiology, Nuclear Medicine and Medical Imaging
DOI
10.3847/2041-8213/ac6756