First M87 Event Horizon Telescope Results. IX. Detection of Near-horizon Circular Polarization
Journal article, 2023
Event Horizon Telescope (EHT) observations have revealed a bright ring of emission around the supermassive black hole at the center of the M87 galaxy. EHT images in linear polarization have further identified a coherent spiral pattern around the black hole, produced from ordered magnetic fields threading the emitting plasma. Here we present the first analysis of circular polarization using EHT data, acquired in 2017, which can potentially provide additional insights into the magnetic fields and plasma composition near the black hole. Interferometric closure quantities provide convincing evidence for the presence of circularly polarized emission on event-horizon scales. We produce images of the circular polarization using both traditional and newly developed methods. All methods find a moderate level of resolved circular polarization across the image (〈|v|〉 < 3.7%), consistent with the low image-integrated circular polarization fraction measured by the Atacama Large Millimeter/submillimeter Array (|vint| < 1%). Despite this broad agreement, the methods show substantial variation in the morphology of the circularly polarized emission, indicating that our conclusions are strongly dependent on the imaging assumptions because of the limited baseline coverage, uncertain telescope gain calibration, and weakly polarized signal. We include this upper limit in an updated comparison to general relativistic magnetohydrodynamic simulation models. This analysis reinforces the previously reported preference for magnetically arrested accretion flow models. We find that most simulations naturally produce a low level of circular polarization consistent with our upper limit and that Faraday conversion is likely the dominant production mechanism for circular polarization at 230 GHz in M87*
Author
Kazunori Akiyama
Massachusetts Institute of Technology (MIT)
Antxon Alberdi
Institute of Astrophysics of Andalusia (IAA)
Walter Alef
Max Planck Society
Juan-Carlos Algaba
University of Malaya
Richard Anantua
Harvard University
K. Asada
Academia Sinica
R. Azulay
Max Planck Society
U. Bach
Max Planck Society
A. K. Baczko
Max Planck Society
David Ball
University of Arizona
Mislav Baloković
Yale University
John Barrett
Massachusetts Institute of Technology (MIT)
M. Bauböck
University of Illinois
Bradford A. Benson
Fermi National Accelerator Laboratory
Dan Bintley
East Asian Observatory
Lindy Blackburn
Harvard University
R. Blundell
Harvard-Smithsonian Center for Astrophysics
K. L. Bouman
California Institute of Technology (Caltech)
G. C. Bower
Academia Sinica
Hope Boyce
McGill University
M. Bremer
Institut de Radioastronomie Millimétrique (IRAM)
C. D. Brinkerink
Radboud University
Roger Brissenden
Harvard University
Silke Britzen
Max Planck Society
Avery E. Broderick
Perimeter Institute for Theoretical Physics
D. Broguière
Institut de Radioastronomie Millimétrique (IRAM)
Thomas Bronzwaer
Radboud University
Sandra Bustamente
University of Massachusetts
Do Young Byun
Korea Astronomy and Space Science Institute
J. E. Carlstrom
University of Chicago
Chiara Ceccobello
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
A. Chael
Princeton University
Chi Kwan Chan
University of Arizona
Dominic O. Chang
Harvard University
Koushik Chatterjee
Harvard University
S. Chatterjee
Cornell University
Ming Tang Chen
Academia Sinica
Yongjun Chen
Shanghai Astronomical Observatory
X. P. Cheng
Korea Astronomy and Space Science Institute
I. Cho
Institute of Astrophysics of Andalusia (IAA)
Pierre Christian
Fairfield University
Nicholas S. Conroy
Harvard-Smithsonian Center for Astrophysics
John Conway
Chalmers, Space, Earth and Environment, Onsala Space Observatory
James M. Cordes
Cornell University
Thomas M. Crawford
University of Chicago
G. Crew
Massachusetts Institute of Technology (MIT)
Alejandro Cruz-Osorio
Universidad Nacional Autónoma de México
Yuzhu Cui
Zhejiang Lab
Rohan Dahale
Institute of Astrophysics of Andalusia (IAA)
Jordy Davelaar
Radboud University
Mariafelicia De Laurentis
Goethe University Frankfurt
R. P. Deane
University of Witwatersrand
Jessica Dempsey
East Asian Observatory
Gregory Desvignes
Max Planck Society
Jason Dexter
JILA
Vedant Dhruv
University of Illinois
S. Doeleman
Harvard University
Sean Dougal
University of Arizona
Sergio A. Dzib
Max Planck Society
Ralph P. Eatough
Max Planck Society
Razieh Emami
Harvard-Smithsonian Center for Astrophysics
H.D. Falcke
Radboud University
Joseph R. Farah
Las Cumbres Observatory Global Telescope Network
V. Fish
Massachusetts Institute of Technology (MIT)
E. Fomalont
National Radio Astronomy Observatory
H. Alyson Ford
University of Arizona
Marianna Foschi
Institute of Astrophysics of Andalusia (IAA)
R. Fraga-Encinas
Radboud University
William T. Freeman
Massachusetts Institute of Technology (MIT)
P. Friberg
East Asian Observatory
Christian M. Fromm
Max Planck Society
Antonio Fuentes
Institute of Astrophysics of Andalusia (IAA)
Peter Galison
Harvard University
Charles F. Gammie
University of Illinois
Roberto Garcia
Institut de Radioastronomie Millimétrique (IRAM)
Olivier Gentaz
Institut de Radioastronomie Millimétrique (IRAM)
Boris Georgiev
Perimeter Institute for Theoretical Physics
C. Goddi
University of Sao Paulo (USP)
R. Gold
University of Southern Denmark
Arturo I. Gómez-Ruiz
National Institute of Astrophysics, Optics and Electronics
J. L. Gomez
Institute of Astrophysics of Andalusia (IAA)
Minfeng Gu
Shanghai Astronomical Observatory
M. Gurwell
Harvard-Smithsonian Center for Astrophysics
K. Hada
National Astronomical Observatory of Japan
Daryl Haggard
McGill University
Kari Haworth
Harvard-Smithsonian Center for Astrophysics
Michael H. Hecht
Massachusetts Institute of Technology (MIT)
R. Hesper
University of Groningen
Dirk Heumann
University of Arizona
Luis C. Ho
Beijing University of Technology
P. T. P. Ho
Academia Sinica
Mareki Honma
National Astronomical Observatory of Japan
Chih Wei L. Huang
Academia Sinica
Lei Huang
Shanghai Astronomical Observatory
D. Hughes
National Institute of Astrophysics, Optics and Electronics
Shiro Ikeda
National Astronomical Observatory of Japan
C.M. Violette Impellizzeri
National Radio Astronomy Observatory
Makoto Inoue
Academia Sinica
S. Issaoun
Harvard-Smithsonian Center for Astrophysics
David J. James
ASTRAVEO
Buell T. Jannuzi
University of Arizona
Michael Janssen
Max Planck Society
Britton Jeter
Academia Sinica
Wu Jiang
Shanghai Astronomical Observatory
Alejandra Jimenez-Rosales
Radboud University
Michael D. Johnson
Harvard University
S.G. Jorstad
Boston University
Abhishek V. Joshi
University of Illinois
Taehyun Jung
Korea Astronomy and Space Science Institute
Mansour Karami
Perimeter Institute for Theoretical Physics
R. Karuppusamy
Max Planck Society
Tomohisa Kawashima
University of Tokyo
G. Keating
Harvard-Smithsonian Center for Astrophysics
M. M. Kettenis
Joint Institute for VLBI in Europe (JIVE)
Dong-Jin Kim
Max Planck Society
Jae-Young Kim
Max Planck Society
Jongsoo Kim
Korea Astronomy and Space Science Institute
Junhan Kim
California Institute of Technology (Caltech)
M. Kino
National Astronomical Observatory of Japan
Jun Yi Koay
Academia Sinica
Prashant Kocherlakota
Goethe University Frankfurt
Yutaro Kofuji
National Astronomical Observatory of Japan
Patrick M. Koch
Academia Sinica
Shoko Koyama
Academia Sinica
C. Kramer
Institut de Radioastronomie Millimétrique (IRAM)
Joana A. Kramer
Max Planck Society
M. Kramer
Max Planck Society
T.P. Krichbaum
Max Planck Society
Greg Lindahl
Academia Sinica
Michael Lindqvist
Radboud University
Tod R. Lauer
National Optical Astronomy Observatory
Daeyoung Lee
University of Illinois
Sang Sung Lee
Korea Astronomy and Space Science Institute
Po Kin Leung
Chinese University of Hong Kong
Aviad Levis
California Institute of Technology (Caltech)
Zhiyuan Li
Nanjing University
R. Lico
Institute of Astrophysics of Andalusia (IAA)
Greg Lindahl
Harvard-Smithsonian Center for Astrophysics
Michael Lindqvist
Chalmers, Space, Earth and Environment, Onsala Space Observatory
Mikhail Lisakov
Max Planck Society
Jun Liu
Max Planck Society
Kuo Liu
Max Planck Society
Elisabetta Liuzzo
Istituto di Radioastronomia
Wen-Ping Lo
Academia Sinica
A. P. Lobanov
Max Planck Society
L. Loinard
Universidad Nacional Autónoma de México
Colin Lonsdale
Massachusetts Institute of Technology (MIT)
Amy E. Lowitz
University of Arizona
R.S. Lu
Max Planck Society
N. R. Macdonald
Max Planck Society
Jirong Mao
Yunnan Observatories
Nicola Marchili
Max Planck Society
S. Markoff
Anton Pannekoek Institute for Astronomy
D. P. Marrone
University of Arizona
A. Marscher
Boston University
Ivan Marti-Vidal
Universitat de Valencia
S. Matsushita
Academia Sinica
Lynn D. Matthews
Massachusetts Institute of Technology (MIT)
Lia Medeiros
Princeton University
K. Menten
Max Planck Society
Daniel Michalik
University of Chicago
Izumi Mizuno
East Asian Observatory
Yosuke Mizuno
Goethe University Frankfurt
James M. Moran
Harvard University
Kotaro Moriyama
Massachusetts Institute of Technology (MIT)
M. Mościbrodzka
Radboud University
Wanga Mulaudzi
Anton Pannekoek Institute for Astronomy
C. Müller
Max Planck Society
Hendrik Müller
Max Planck Society
A. Mus
Universitat de Valencia
Gibwa Musoke
Radboud University
I. Myserlis
Shanghai Jiao Tong University
Andrew Nadolski
University of Illinois
H. Nagai
National Astronomical Observatory of Japan
N. M. Nagar
University of Concepcion
Masanori Nakamura
Academia Sinica
Ramesh Narayan
Harvard University
Gopal Narayanan
University of Massachusetts
Iniyan Natarajan
Harvard University
Antonios Nathanail
Goethe University Frankfurt
Santiago Navarro Fuentes
Institut de Radioastronomie Millimétrique (IRAM)
Joey Neilsen
Villanova University
R. Neri
Institut de Radioastronomie Millimétrique (IRAM)
Chunchong Ni
Perimeter Institute for Theoretical Physics
A. Noutsos
Max Planck Society
Michael A. Nowak
Washington University in St. Louis
Junghwan Oh
Sejong University
Hiroki Okino
National Astronomical Observatory of Japan
Héctor Olivares
Radboud University
G.N. Ortiz-León
Max Planck Society
Tomoaki Oyama
National Astronomical Observatory of Japan
Feryal Özel
Georgia Institute of Technology
Daniel C.M. Palumbo
Harvard University
Georgios Filippos Paraschos
Max Planck Society
Jongho Park
Kyung Hee University
Harriet Parsons
East Asian Observatory
N. Patel
Harvard-Smithsonian Center for Astrophysics
U. L. Pen
Academia Sinica
Dominic W. Pesce
Harvard University
Vincent Piétu
Institut de Radioastronomie Millimétrique (IRAM)
Richard L. Plambeck
University of California
Aleksandar PopStefanija
University of Massachusetts
Oliver Porth
Goethe University Frankfurt
Felix M. Pötzl
Max Planck Society
Ben Prather
University of Illinois
Jorge A. Preciado-López
Perimeter Institute for Theoretical Physics
Dimitrios Psaltis
Georgia Institute of Technology
Hung-Yi Pu
Academia Sinica
Venkatessh Ramakrishnan
University of Concepcion
R. Rao
Harvard-Smithsonian Center for Astrophysics
M.G. Rawlings
East Asian Observatory
Alexander W. Raymond
Harvard University
Luciano Rezzolla
Goethe University Frankfurt
Angelo Ricarte
Harvard University
Bart Ripperda
Perimeter Institute for Theoretical Physics
F. Roelofs
Harvard University
A.E.E. Rogers
Massachusetts Institute of Technology (MIT)
C. Romero-Cañizales
Academia Sinica
Eduardo Ros
Max Planck Society
Arash Roshanineshat
University of Arizona
H. Rottmann
Max Planck Society
A. Roy
Max Planck Society
Ignacio Ruiz
Institut de Radioastronomie Millimétrique (IRAM)
C. Ruszczyk
Massachusetts Institute of Technology (MIT)
Kazi L.J. Rygl
Istituto di Radioastronomia
S. Sanchez
Institut de Radioastronomie Millimétrique (IRAM)
David Sánchez-Arguelles
National Institute of Astrophysics, Optics and Electronics
M. Sánchez Portal
Institut de Radioastronomie Millimétrique (IRAM)
Mahito Sasada
National Astronomical Observatory of Japan
Kaushik Satapathy
University of Arizona
T. Savolainen
Max Planck Society
T. Savolainen
University of Massachusetts
Jonathan Schonfeld
Harvard-Smithsonian Center for Astrophysics
K. Schuster
Institut de Radioastronomie Millimétrique (IRAM)
Lijing Shao
Max Planck Society
Zhi Qiang Shen
Shanghai Astronomical Observatory
Des Small
Joint Institute for VLBI in Europe (JIVE)
B. W. Sohn
Korea Astronomy and Space Science Institute
J. SooHoo
Massachusetts Institute of Technology (MIT)
León David Sosapanta Salas
Anton Pannekoek Institute for Astronomy
Kamal Souccar
University of Massachusetts
He Sun
Beijing University of Technology
Fumie Tazaki
National Astronomical Observatory of Japan
Alexandra J. Tetarenko
University of Lethbridge
Paul Tiede
Harvard University
R. P. J. Tilanus
University of Arizona
M. Titus
Massachusetts Institute of Technology (MIT)
Pablo Torne
Max Planck Society
Teresa Toscano
Institute of Astrophysics of Andalusia (IAA)
E. Traianou
Institute of Astrophysics of Andalusia (IAA)
Tyler Trent
University of Arizona
S. Trippe
Seoul National University
Matthew Turk
University of Illinois
I. van Bemmel
Joint Institute for VLBI in Europe (JIVE)
H. J. van Langevelde
Leiden University
Daniel R. van Rossum
Radboud University
Jesse Vos
Radboud University
Jan Wagner
Max Planck Society
D. Ward-Thompson
University of Central Lancashire
John Wardle
Brandeis University
Jasmin E. Washington
University of Arizona
J. Weintroub
Harvard University
Robert Wharton
Max Planck Society
M. Wielgus
Max Planck Society
K. Wiik
Tuorla Observatory
Gunther Witzel
Max Planck Society
Michael F. Wondrak
Radboud University
George N. Wong
Princeton University
Qingwen Wu
Huazhong University of Science and Technology
Nitika Yadlapalli
California Institute of Technology (Caltech)
Paul Yamaguchi
Harvard-Smithsonian Center for Astrophysics
Aristomenis Yfantis
Radboud University
Doosoo Yoon
Anton Pannekoek Institute for Astronomy
A. Young
Radboud University
K. Young
Harvard-Smithsonian Center for Astrophysics
Ziri Younsi
Goethe University Frankfurt
Wei Yu
Harvard-Smithsonian Center for Astrophysics
Feng Yuan
Shanghai Astronomical Observatory
Ye-Fei Yuan
University of Science and Technology of China
A.J. Zensus
Max Planck Society
Shuo Zhang
Michigan State University
G. Y. Zhao
Institute of Astrophysics of Andalusia (IAA)
Shan-Shan Zhao
Shanghai Astronomical Observatory
Astrophysical Journal Letters
2041-8205 (ISSN) 2041-8213 (eISSN)
Vol. 957 2 L20RadioNet 4
European Commission (EC) (EC/H2020/730562), 2017-01-01 -- 2020-12-31.
Onsala space observatory infrastructure
Swedish Research Council (VR) (2017-00648), 2018-01-01 -- 2021-12-31.
Subject Categories
Astronomy, Astrophysics and Cosmology
DOI
10.3847/2041-8213/acff70