Origin of the ring ellipticity in the black hole images of M87
Artikel i vetenskaplig tidskrift, 2025
We investigate the origin of the elliptical ring structure observed in the images of the supermassive black hole M87∗, aiming to disentangle contributions from gravitational, astrophysical, and imaging effects. Leveraging the enhanced capabilities of the Event Horizon Telescope (EHT)’s 2018 array, including improved (u, v)-coverage from the Greenland Telescope, we measured the ring’s ellipticity using five independent imaging methods, obtaining a consistent average value of τ = 0.08+−000302 with a position angle of ξ = 50.1−+7662 degrees. To interpret this measurement, we compared it to general relativistic magnetohydrodynamic (GRMHD) simulations spanning a wide range of physical parameters including the thermal or nonthermal electron distribution function, spins, and ion-to-electron temperature ratios in both low- and high-density regions. We find no statistically significant correlation between spin and ellipticity in GRMHD images. Instead, we identify a correlation between ellipticity and the fraction of non-ring emission, particularly in nonthermal models and models with higher jet emission. These results indicate that the ellipticity measured from the M87∗ emission structure is consistent with that expected from simulations of turbulent accretion flows around black holes, where it is dominated by astrophysical effects rather than gravitational ones. Future high-resolution imaging, including space very long baseline interferometry and long-term monitoring, will be essential to isolate gravitational signatures from astrophysical effects.
gravitation
accretion, accretion disks
galaxies: active
black hole physics
Författare
Rohan Dahale
Consejo Superior de Investigaciones Científicas (CSIC)
I. Cho
Korea Astronomy and Space Science Institute
Yonsei University
Consejo Superior de Investigaciones Científicas (CSIC)
Kotaro Moriyama
National Astronomical Observatory of Japan
Consejo Superior de Investigaciones Científicas (CSIC)
K. Wiik
Tuorla Observatory
Turun Yliopisto
Aalto-Yliopisto
Paul Tiede
Harvard-Smithsonian Center for Astrophysics
Harvard University
J. L. Gomez
Consejo Superior de Investigaciones Científicas (CSIC)
Chi Kwan Chan
University of Arizona
R. Gold
Institut für Theoretische Physik Heidelberg
Universität Heidelberg
Syddansk Universitet
Vadim Y. Bernshteyn
University of Arizona
Marianna Foschi
Consejo Superior de Investigaciones Científicas (CSIC)
Britton Jeter
Academia Sinica
Hung-Yi Pu
Academia Sinica
National Taiwan Normal University
Boris Georgiev
University of Arizona
Abhishek V. Joshi
The Grainger College of Engineering
Alejandro Cruz-Osorio
Johann Wolfgang Goethe Universität Frankfurt am Main
Universidad Nacional Autónoma de México
Iniyan Natarajan
Harvard University
Harvard-Smithsonian Center for Astrophysics
Avery E. Broderick
University of Waterloo
Perimeter Institute for Theoretical Physics
León David Sosapanta Salas
Anton Pannekoek Institute for Astronomy
Koushik Chatterjee
University of Maryland
Kazunori Akiyama
Massachusetts Institute of Technology (MIT)
Harvard University
National Astronomical Observatory of Japan
E. Albentosa-Ruiz
Universitat de Valencia
Antxon Alberdi
Consejo Superior de Investigaciones Científicas (CSIC)
Walter Alef
Max-Planck-Gesellschaft
Juan-Carlos Algaba
University of Malaya
Richard Anantua
Rice University
University of Texas
Harvard-Smithsonian Center for Astrophysics
Harvard University
K. Asada
Academia Sinica
R. Azulay
Universitat de Valencia
Max-Planck-Gesellschaft
U. Bach
Max-Planck-Gesellschaft
A. K. Baczko
Max-Planck-Gesellschaft
David Ball
University of Arizona
Mislav Baloković
Yale University
Bidisha Bandyopadhyay
Universidad de Concepción
John Barrett
Massachusetts Institute of Technology (MIT)
M. Bauböck
The Grainger College of Engineering
Bradford A. Benson
Fermi National Accelerator Laboratory
University of Chicago
Dan Bintley
James Clerk Maxwell Telescope
East Asian Observatory
Lindy Blackburn
Harvard-Smithsonian Center for Astrophysics
Harvard University
R. Blundell
Harvard-Smithsonian Center for Astrophysics
K. L. Bouman
California Institute of Technology (Caltech)
G. C. Bower
Academia Sinica
University of Hawaii
M. Bremer
Institut de Radioastronomie Millimétrique (IRAM)
Roger Brissenden
Harvard-Smithsonian Center for Astrophysics
Harvard University
Silke Britzen
Max-Planck-Gesellschaft
D. Broguière
Institut de Radioastronomie Millimétrique (IRAM)
Thomas Bronzwaer
Radboud Universiteit
Sandra Bustamente
University of Massachusetts
Douglas Ferreira Carlos
Universidade de Sao Paulo (USP)
J. E. Carlstrom
University of Chicago
The Enrico Fermi Institute
A. Chael
Princeton University
Dominic O. Chang
Harvard University
Harvard-Smithsonian Center for Astrophysics
S. Chatterjee
Cornell University
Ming Tang Chen
Academia Sinica
Yongjun Chen
Chinese Academy of Sciences
X. P. Cheng
Korea Astronomy and Space Science Institute
Pierre Christian
WattTime
Nicholas S. Conroy
Harvard-Smithsonian Center for Astrophysics
University of Illinois
John Conway
Chalmers, Rymd-, geo- och miljövetenskap, Onsala rymdobservatorium
Thomas M. Crawford
University of Chicago
G. Crew
Massachusetts Institute of Technology (MIT)
Yuzhu Cui
Shanghai Jiao Tong University
Zhejiang Lab
Brandon Curd
Harvard University
University of Texas
Harvard-Smithsonian Center for Astrophysics
Jordy Davelaar
Princeton University
Mariafelicia De Laurentis
Universita degli Studi di Napoli Federico II
Istituto Nazionale di Fisica Nucleare
R. P. Deane
Rhodes University
Universiteit van Pretoria
University of Witwatersrand
Jessica Dempsey
James Clerk Maxwell Telescope
Netherlands Institute for Radio Astronomy (ASTRON)
East Asian Observatory
Gregory Desvignes
Max-Planck-Gesellschaft
Observatoire de Paris
Jason Dexter
JILA
Vedant Dhruv
The Grainger College of Engineering
Indu K. Dihingia
Shanghai Jiao Tong University
S. Doeleman
Harvard University
Harvard-Smithsonian Center for Astrophysics
Sergio A. Dzib
Max-Planck-Gesellschaft
Ralph P. Eatough
Chinese Academy of Sciences
Max-Planck-Gesellschaft
Razieh Emami
Harvard-Smithsonian Center for Astrophysics
H.D. Falcke
Radboud Universiteit
Joseph R. Farah
Las Cumbres Observatory Global Telescope Network
University of California
V. Fish
Massachusetts Institute of Technology (MIT)
E. Fomalont
National Radio Astronomy Observatory
H.D. Falcke
University of Arizona
R. Fraga-Encinas
Radboud Universiteit
William T. Freeman
Massachusetts Institute of Technology (MIT)
Google Inc.
P. Friberg
James Clerk Maxwell Telescope
East Asian Observatory
Christian M. Fromm
Max-Planck-Gesellschaft
Julius-Maximilians Universität Würzburg
Johann Wolfgang Goethe Universität Frankfurt am Main
Antonio Fuentes
Consejo Superior de Investigaciones Científicas (CSIC)
Peter Galison
Harvard University
Charles F. Gammie
The Grainger College of Engineering
University of Illinois
Roberto Garcia
Institut de Radioastronomie Millimétrique (IRAM)
Olivier Gentaz
Institut de Radioastronomie Millimétrique (IRAM)
Gertie Geertsema
Royal Netherlands Meteorological Institute
C. Goddi
Istituto Nazionale di Fisica Nucleare
Universita degli Studi di Cagliari
Istituto nazionale di astrofisica (INAF)
Universidade de Sao Paulo (USP)
Arturo I. Gómez-Ruiz
Instituto Nacional de Astrofísica, Óptica y Electrońica
Consejo Nacional de Ciencia y Tecnologia Mexico
Minfeng Gu
Chinese Academy of Sciences
M. Gurwell
Harvard-Smithsonian Center for Astrophysics
K. Hada
National Astronomical Observatory of Japan
Graduate School of Pharmaceutical Sciences
Daryl Haggard
McGill University
R. Hesper
Rijksuniversiteit Groningen
Dirk Heumann
University of Arizona
Luis C. Ho
Beijing University of Technology
P. T. P. Ho
Academia Sinica
James Clerk Maxwell Telescope
East Asian Observatory
Mareki Honma
The Graduate University for Advanced Studies (SOKENDAI)
University of Tokyo
National Astronomical Observatory of Japan
Chih Wei L. Huang
Academia Sinica
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 699 A279RadioNet 4
Europeiska kommissionen (EU) (EC/H2020/730562), 2017-01-01 -- 2020-12-31.
Onsala rymdobservatorium infrastruktur
Vetenskapsrådet (VR) (2017-00648), 2018-01-01 -- 2021-12-31.
Ämneskategorier (SSIF 2025)
Astronomi, astrofysik och kosmologi
DOI
10.1051/0004-6361/202555235