@article{3068491,
    title = "First M87 Event Horizon Telescope Results. VIII. Magnetic Field Structure near the Event Horizon",
    author = "Akiyama, K. and Algaba, J.C. and Alberdi, A. and Alef, W. and Anantua, R. and Asada, K. and Azulay, R. and Baczko, A.-K. and Ball, D. and Baloković, M. and Barrett, J. and Benson, B.A. and Bintley, D. and Blackburn, L. and Blundell, R. and Boland, W. and Bouman, K.L. and Bower, G.C. and Boyce, H. and Bremer, M. and Brinkerink, C.D. and Brissenden, R. and Britzen, S. and Broderick, A.E. and Broguiere, D. and Bronzwaer, T. and Byun, D.-Y. and Carlstrom, J.E. and Chael, A. and Chan, C.-K. and Chatterjee, S. and Chatterjee, K. and Chen, M.-T. and Chen, Y. and Chesler, P.M. and Cho, I. and Christian, P. and Conway, J.E. and Cordes, J.M. and Crawford, T.M. and Crew, G.B. and Cruz-Osorio, A. and Cui, Y. and Davelaar, J. and De Laurentis, M. and Deane, R. and Dempsey, J. and Desvignes, G. and Dexter, J. and Doeleman, S.S. and Eatough, R.P. and Falcke, H. and Farah, J. and Fish, V.L. and Fomalont, E. and Ford, H.A. and Fraga-Encinas, R. and Friberg, P. and Fromm, C.M. and Fuentes, A. and Galison, P. and Gammie, C.F. and Garciá, R. and Gelles, Z. and Gentaz, O. and Georgiev, B. and Goddi, C. and Gold, R. and Gómez, J.L. and Gómez-Ruiz, A.I. and Gu, M. and Gurwell, M. and Hada, K. and Haggard, D. and Hecht, M.H. and Hesper, R. and Himwich, E. and Ho, L.C. and Ho, P. and Honma, M. and Huang, C.-W.L. and Huang, L. and Hughes, D.H. and Ikeda, S. and Inoue, M. and Issaoun, S. and James, D.J. and Jannuzi, B.T. and Janssen, M. and Jeter, B. and Jiang, W. and Jimenez-Rosales, A. and Johnson, M.D. and Jorstad, S. and Jung, T. and Karami, M. and Karuppusamy, R. and Kawashima, T. and Keating, G.K. and Kettenis, M. and Kim, D.-J. and Kim, J.-Y. and Kim, J. and Kim, J. and Kino, M. and Koay, J.Y. and Kofuji, Y. and Koch, P.M. and Koyama, S. and Kramer, M. and Kramer, C. and Krichbaum, T.P. and Kuo, C.-Y. and Lauer, T.R. and Lee, S.-S. and Levis, A. and Li, Y.-R. and Li, Z. and Lindqvist, M. and Lico, R. and Lindahl, G. and Liu, J. and Liu, K. and Liuzzo, E. and Lo, W.-P. and Lobanov, A.P. and Loinard, L. and Lonsdale, C. and Lu, R.-S. and Macdonald, N.R. and Mao, J. and Marchili, N. and Markoff, S. and Marrone, D.P. and Marscher, A.P. and Martí-Vidal, I. and Matsushita, S. and Matthews, L.D. and Medeiros, L. and Menten, K.M. and Mizuno, I. and Mizuno, Y. and Moran, J.M. and Moriyama, K. and Moscibrodzka, M. and Müller, C. and Musoke, G. and Mejiás, A.M. and Michalik, D. and Nadolski, A. and Nagai, H. and Nagar, N.M. and Nakamura, M. and Narayan, R. and Narayanan, G. and Natarajan, I. and Nathanail, A. and Neilsen, J. and Neri, R. and Ni, C. and Noutsos, A. and Nowak, M.A. and Okino, H. and Olivares, H. and Ortiz-León, G.N. and Oyama, T. and zel, F. and Palumbo, D.C.M. and Park, J. and Patel, N. and Pen, U.-L. and Pesce, D.W. and Piétu, V. and Plambeck, R. and Popstefanija, A. and Porth, O. and Pötzl, F.M. and Prather, B. and Preciado-López, J.A. and Psaltis, D. and Pu, H.-Y. and Ramakrishnan, V. and Rao, R. and Rawlings, M.G. and Raymond, A.W. and Rezzolla, L. and Ricarte, A. and Ripperda, B. and Roelofs, F. and Rogers, A. and Ros, E. and Rose, M. and Roshanineshat, A. and Rottmann, H. and Roy, A.L. and Ruszczyk, C. and Rygl, K.L.J. and Sánchez, S. and Sánchez-Arguelles, D. and Sasada, M. and Savolainen, T. and Schloerb, F.P. and Schuster, K.-F. and Shao, L. and Shen, Z. and Small, D. and Sohn, B.W. and Soohoo, J. and Sun, H. and Tazaki, F. and Tetarenko, A.J. and Tiede, P. and Tilanus, R.P.J. and Titus, M. and Toma, K. and Torne, P. and Trent, T. and Traianou, E. and Trippe, S. and Bemmel, I.V. and Van Langevelde, H.J. and Van Rossum, D.R. and Wagner, J. and Ward-Thompson, D. and Wardle, J. and Weintroub, J. and Wex, N. and Wharton, R. and Wielgus, M. and Wong, G.N. and Wu, Q. and Yoon, D. and Young, A. and Young, K. and Younsi, Z. and Yuan, F. and Yuan, Y.-F. and Zensus, J.A. and Zhao, G.-Y. and Zhao, S.-S.",
    journal = "The Astrophysical Journal Letters",
    year = "2021",
    volume = "910",
    number = "1",
    publisher = "American Astronomical Society",
    issn = "2041-8205, 2041-8213",
    doi = "10.3847/2041-8213/abe4de",
    abstract = "Event Horizon Telescope (EHT) observations at 230 GHz have now imaged polarized emission around the supermassive black hole in M87 on event-horizon scales. This polarized synchrotron radiation probes the structure of magnetic fields and the plasma properties near the black hole. Here we compare the resolved polarization structure observed by the EHT, along with simultaneous unresolved observations with the Atacama Large Millimeter/submillimeter Array, to expectations from theoretical models. The low fractional linear polarization in the resolved image suggests that the polarization is scrambled on scales smaller than the EHT beam, which we attribute to Faraday rotation internal to the emission region. We estimate the average density n e ∼ 104-7 cm-3, magnetic field strength B ∼ 1-30 G, and electron temperature T e ∼ (1-12) 1010 K of the radiating plasma in a simple one-zone emission model. We show that the net azimuthal linear polarization pattern may result from organized, poloidal magnetic fields in the emission region. In a quantitative comparison with a large library of simulated polarimetric images from general relativistic magnetohydrodynamic (GRMHD) simulations, we identify a subset of physical models that can explain critical features of the polarimetric EHT observations while producing a relativistic jet of sufficient power. The consistent GRMHD models are all of magnetically arrested accretion disks, where near-horizon magnetic fields are dynamically important. We use the models to infer a mass accretion rate onto the black hole in M87 of (3-20) 10-4 M o˙ yr-1. © 2021. The Author(s). Published by the American Astronomical Society.."
}