The Polarized Image of a Synchrotron-emitting Ring of Gas Orbiting a Black Hole

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Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2021-05-01
Department
Harvard University
University of Colorado Boulder
University of Illinois at Urbana-Champaign
Princeton University
CSIC
Max Planck Institute for Radio Astronomy
University of Malaya
Academia Sinica - Institute of Astronomy and Astrophysics
University of Arizona
Massachusetts Institute of Technology
United States Department of Energy
East Asian Observatory
Nederlandse Onderzoekschool voor Astronomie (NOVA)
McGill University
Institut de Radio Astronomie Millimétrique
Radboud University Nijmegen
Perimeter Institute for Theoretical Physics
Korea Astronomy and Space Science Institute
University of Chicago
Cornell Center for Astrophysics and Planetary Science
University of Amsterdam
CAS - Shanghai Astronomical Observatory
Fairfield University
Chalmers University of Technology
Goethe University Frankfurt
National Astronomical Observatory of Japan
University of the Witwatersrand
Observatoire de Paris
National Radio Astronomy Observatory
University of Waterloo
Instituto Nacional de Astrofisica Optica y Electronica
University of Groningen
Peking University
Boston University
The University of Tokyo
Joint Institute for VLBI in Europe
National Optical Astronomy Observatory
California Institute of Technology
CAS - Institute of High Energy Physics
Nanjing University
INAF - Istituto di Radioastronomia
Instituto de Radioastronomía y Astrofísica
CAS - National Astronomical Observatories
Universidad de Valencia
Universidad de Concepción
Villanova University
Washington University St. Louis
University of California Berkeley
University of Massachusetts
Simons Foundation
IRAM
Anne Lähteenmäki Group
Tohoku University
Seoul National University
University of Central Lancashire
Brandeis University
Huazhong University of Science and Technology
University of Science and Technology of China
Department of Electronics and Nanoengineering
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Mcode
Degree programme
Language
en
Pages
26
Series
Astrophysical Journal, Volume 912, issue 1
Abstract
Synchrotron radiation from hot gas near a black hole results in a polarized image. The image polarization is determined by effects including the orientation of the magnetic field in the emitting region, relativistic motion of the gas, strong gravitational lensing by the black hole, and parallel transport in the curved spacetime. We explore these effects using a simple model of an axisymmetric, equatorial accretion disk around a Schwarzschild black hole. By using an approximate expression for the null geodesics derived by Beloborodov and conservation of the Walker-Penrose constant, we provide analytic estimates for the image polarization. We test this model using currently favored general relativistic magnetohydrodynamic simulations of M87∗, using ring parameters given by the simulations. For a subset of these with modest Faraday effects, we show that the ring model broadly reproduces the polarimetric image morphology. Our model also predicts the polarization evolution for compact flaring regions, such as those observed from Sgr A∗ with GRAVITY. With suitably chosen parameters, our simple model can reproduce the EVPA pattern and relative polarized intensity in Event Horizon Telescope images of M87∗. Under the physically motivated assumption that the magnetic field trails the fluid velocity, this comparison is consistent with the clockwise rotation inferred from total intensity images.
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Publisher Copyright: © 2021 The Author(s). Published by the American Astronomical Society.. Copyright: Copyright 2021 Elsevier B.V., All rights reserved. | openaire: EC/H2020/730562/EU//RadioNet
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Narayan , R , Palumbo , D C M , Johnson , M D , Gelles , Z , Himwich , E , Chang , D O , Ricarte , A , Dexter , J , Gammie , C F , Chael , A A , Akiyama , K , Alberdi , A , Alef , W , Algaba , J C , Anantua , R , Asada , K , Azulay , R , Baczko , A K , Ball , D , Baloković , M , Barrett , J , Benson , B A , Bintley , D , Blackburn , L , Blundell , R , Boland , W , Bouman , K L , Bower , G C , Boyce , H , Bremer , M , Brinkerink , C D , Brissenden , R , Britzen , S , Broderick , A E , Broguiere , D , Bronzwaer , T , Byun , D Y , Carlstrom , J E , Chan , C K , Chatterjee , S , Chatterjee , K , Chen , M T , Chen , Y , Chesler , P M , Cho , I , Christian , P , Conway , J E , Cordes , J M , Crawford , T M , Crew , G B , Cruz-Osorio , A , Cui , Y , Davelaar , J , De Laurentis , M , Deane , R , Dempsey , J , Desvignes , G , Doeleman , S S , Eatough , R P , Falcke , H , Farah , J , Fish , V L , Fomalont , E , Ford , H A , Fraga-Encinas , R , Friberg , P , Fromm , C M , Fuentes , A , Galison , P , García , R , Gentaz , O , Georgiev , B , Goddi , C , Gold , R , Gómez , J L , Gómez-Ruiz , A I , Gu , M , Gurwell , M , Hada , K , Haggard , D , Hecht , M H , Hesper , R , Ho , L C , Ho , P , Honma , M , Huang , C W L , Huang , L , Hughes , D H , Ikeda , S , Inoue , M , Issaoun , S , James , D J , Jannuzi , B T , Janssen , M , Jeter , B , Jiang , W , Jimenez-Rosales , A , Jorstad , S , Jung , T , Karami , M , Karuppusamy , R , Kawashima , T , Keating , G K , Kettenis , M , Kim , D J , Kim , J Y , Kim , J , Kim , J , Kino , M , Koay , J Y , Kofuji , Y , Koch , P M , Koyama , S , Kramer , M , Kramer , C , Krichbaum , T P , Kuo , C Y , Lauer , T R , Lee , S S , Levis , A , Li , Y R , Li , Z , Lindqvist , M , Lico , R , Lindahl , G , Liu , J , Liu , K , Liuzzo , E , Lo , W P , Lobanov , A P , Loinard , L , Lonsdale , C , Lu , R S , Macdonald , N R , Mao , J , Marchili , N , Markoff , S , Marrone , D P , Marscher , A P , Martí-Vidal , I , Matsushita , S , Matthews , L D , Medeiros , L , Menten , K M , Mizuno , I , Mizuno , Y , Moran , J M , Moriyama , K , Moscibrodzka , M , Müller , C , Musoke , G , Mejías , A M , Nagai , H , Nagar , N M , Nakamura , M , Natarajan , I , Nathanail , A , Neilsen , J , Neri , R , Ni , C , Noutsos , A , Nowak , M A , Okino , H , Olivares , H , Ortiz-León , G N , Oyama , T , Özel , F , Park , J , Patel , N , Pen , U L , Pesce , D W , Piétu , V , Plambeck , R , Popstefanija , A , Porth , O , Pötzl , F M , Prather , B , Preciado-López , J A , Psaltis , D , Pu , H Y , Ramakrishnan , V , Rao , R , Rawlings , M G , Raymond , A W , Rezzolla , L , Ripperda , B , Roelofs , F , Rogers , A , Ros , E , Rose , M , Roshanineshat , A , Rottmann , H , Roy , A L , Ruszczyk , C , Rygl , K L J , Sánchez , S , Sánchez-Arguelles , D , Sasada , M , Savolainen , T , Schloerb , F P , Schuster , K F , Shao , L , Shen , Z , Small , D , Sohn , B W , Soohoo , J , Sun , H , Tazaki , F , Tetarenko , A J , Tiede , P , Tilanus , R P J , Titus , M , Toma , K , Torne , P , Trent , T , Traianou , E , Trippe , S , Van Bemmel , I , Van Langevelde , H J , Van Rossum , D R , Wagner , J , Ward-Thompson , D , Wardle , J , Weintroub , J , Wex , N , Wharton , R , Wielgus , M , Wong , G N , Wu , Q , Yoon , D , Young , A , Young , K , Younsi , Z , Yuan , F , Yuan , Y F , Zensus , J A , Zhao , G Y & Zhao , S S 2021 , ' The Polarized Image of a Synchrotron-emitting Ring of Gas Orbiting a Black Hole ' , The Astrophysical Journal , vol. 912 , no. 1 , 35 . https://doi.org/10.3847/1538-4357/abf117