@article{3068465,
    title = "Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign",
    author = "Algaba, J.C. and Anczarski, J. and Asada, K. and Baloković, M. and Chandra, S. and Cui, Y.-Z. and Falcone, A.D. and Giroletti, M. and Goddi, C. and Hada, K. and Haggard, D. and Jorstad, S. and Kaur, A. and Kawashima, T. and Keating, G. and Kim, J.-Y. and Kino, M. and Komossa, S. and Kravchenko, E.V. and Krichbaum, T.P. and Lee, S.-S. and Lu, R.-S. and Lucchini, M. and Markoff, S. and Neilsen, J. and Nowak, M.A. and Park, J. and Principe, G. and Ramakrishnan, V. and Reynolds, M.T. and Sasada, M. and Savchenko, S.S. and Williamson, K.E. and Akiyama, K. and Alberdi, A. and Alef, W. and Anantua, R. and Azulay, R. and Baczko, A.-K. and Ball, D. and Barrett, J. and Bintley, D. and Benson, B.A. 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 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 García, R. and Gentaz, O. and Georgiev, B. and Gold, R. and Gómez, J.L. and Gómez-Ruiz, A.I. and Gu, M. and Gurwell, M. and Hecht, M.H. and Hesper, R. 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 Jiménez-Rosales, A. and Johnson, M.D. and Jung, T. and Karami, M. and Karuppusamy, R. and Kettenis, M. and Kim, D.-J. and Kim, J. and Kim, J. and Koay, J.Y. and Kofuji, Y. and Koch, P.M. and Koyama, S. and Kramer, M. and Kramer, C. and Kuo, C.-Y. and Lauer, T.R. 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 Macdonald, N.R. and Mao, J. and Marchili, N. 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 Mejías, A.M. and Nagai, H. and Nagar, N.M. and Nakamura, M. and Narayan, R. and Narayanan, G. and Natarajan, I. and Nathanail, A. and Neri, R. and Ni, C. and Noutsos, A. and Okino, H. and Olivares, H. and Ortiz-León, G.N. and Oyama, T. and Ozel, F. and Palumbo, D.C.M. 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 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 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 Van Bemmel, I. 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. and Principe, G. and Giroletti, M. and D'Ammando, F. and Orienti, M. and Abdalla, H. and Adam, R. and Aharonian, F. and Benkhali, F.A. and Angüner, E.O. and Arcaro, C. and Armand, C. and Armstrong, T. and Ashkar, H. and Backes, M. and Baghmanyan, V. and Barbosa Martins, V. and Barnacka, A. and Barnard, M. and Becherini, Y. and Berge, D. and Bernlöhr, K. and Bi, B. and Böttcher, M. and Boisson, C. and Bolmont, J. and De Bony De Lavergne, M. and Breuhaus, M. and Brun, F. and Brun, P. and Bryan, M. and Büchele, M. and Bulik, T. and Bylund, T. and Caroff, S. and Carosi, A. and Casanova, S. and Chand, T. and Chen, A. and Cotter, G. and Curyło, M. and Damascene Mbarubucyeye, J. and Davids, I.D. and Davies, J. and Deil, C. and Devin, J. and Dewilt, P. and Dirson, L. and Djannati-Ataï, A. and Dmytriiev, A. and Donath, A. and Doroshenko, V. and Duffy, C. and Dyks, J. and Egberts, K. and Eichhorn, F. and Einecke, S. and Emery, G. and Ernenwein, J.-P. and Feijen, K. and Fegan, S. and Fiasson, A. and De Clairfontaine, G.F. and Fontaine, G. and Funk, S. and Füßling, M. and Gabici, S. and Gallant, Y.A. and Giavitto, G. and Giunti, L. and Glawion, D. and Glicenstein, J.F. and Gottschall, D. and Grondin, M.-H. and Hahn, J. and Haupt, M. and Hermann, G. and Hinton, J.A. and Hofmann, W. and Hoischen, C. and Holch, T.L. and Holler, M. and Hörbe, M. and Horns, D. and Huber, D. and Jamrozy, M. and Jankowsky, D. and Jankowsky, F. and Jardin-Blicq, A. and Joshi, V. and Jung-Richardt, I. and Kasai, E. and Kastendieck, M.A. and Katarzyński, K. and Katz, U. and Khangulyan, D. and Khélifi, B. and Klepser, S. and Kluźniak, W. and Komin, N. and Konno, R. and Kosack, K. and Kostunin, D. and Kreter, M. and Lamanna, G. and Lemiere, A. and Lemoine-Goumard, M. and Lenain, J.-P. and Levy, C. and Lohse, T. and Lypova, I. and Mackey, J. and Majumdar, J. and Malyshev, D. and Malyshev, D. and Marandon, V. and Marchegiani, P. and Marcowith, A. and Mares, A. and Martí-Devesa, G. 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A.A. and Artero, M. and Asano, K. and Baack, D. and Babić, A. and Baquero, A. and De Almeida, U.B. and Barrio, J.A. and Becerra González, J. and Bednarek, W. and Bellizzi, L. and Bernardini, E. and Bernardos, M. and Berti, A. and Besenrieder, J. and Bhattacharyya, W. and Bigongiari, C. and Biland, A. and Blanch, O. and Bonnoli, G. and Bošnjak, Ž. and Busetto, G. and Carosi, R. and Ceribella, G. and Cerruti, M. and Chai, Y. and Chilingarian, A. and Cikota, S. and Colak, S.M. and Colombo, E. and Contreras, J.L. and Cortina, J. and Covino, S. and D'Amico, G. and D'Elia, V. and Da Vela, P. and Dazzi, F. and De Angelis, A. and De Lotto, B. and Delfino, M. and Delgado, J. and Delgado Mendez, C. and Depaoli, D. and Di Pierro, F. and Di Venere, L. and Do Souto Espineira, E. and Dominis Prester, D. and Donini, A. and Dorner, D. and Doro, M. and Elsaesser, D. and Fallah Ramazani, V. and Fattorini, A. and Ferrara, G. and Fonseca, M.V. and Font, L. and Fruck, C. and Fukami, S. and García López, R.J. and Garczarczyk, M. and Gasparyan, S. and Gaug, M. and Giglietto, N. and Giordano, F. and Gliwny, P. and Godinović, N. and Green, J.G. and Green, D. and Hadasch, D. and Hahn, A. and Heckmann, L. and Herrera, J. and Hoang, J. and Hrupec, D. and Hütten, M. and Inada, T. and Inoue, S. and Ishio, K. and Iwamura, Y. and Jiménez, I. and Jormanainen, J. and Jouvin, L. and Kajiwara, Y. and Karjalainen, M. and Kerszberg, D. and Kobayashi, Y. and Kubo, H. and Kushida, J. and Lamastra, A. and Lelas, D. and Leone, F. and Lindfors, E. and Lombardi, S. and Longo, F. and López-Coto, R. and López-Moya, M. and López-Oramas, A. and Loporchio, S. and Machado De Oliveira Fraga, B. and Maggio, C. and Majumdar, P. and Makariev, M. and Mallamaci, M. and Maneva, G. and Manganaro, M. and Mannheim, K. and Maraschi, L. and Mariotti, M. and Martínez, M. and Mazin, D. and Menchiari, S. and Mender, S. and Mićanović, S. and Miceli, D. and Miener, T. and Minev, M. and Miranda, J.M. and Mirzoyan, R. and Molina, E. and Moralejo, A. and Morcuende, D. and Moreno, V. and Moretti, E. and Neustroev, V. and Nigro, C. and Nilsson, K. and Nishijima, K. and Noda, K. and Nozaki, S. and Ohtani, Y. and Oka, T. and Otero-Santos, J. and Paiano, S. and Palatiello, M. and Paneque, D. and Paoletti, R. and Paredes, J.M. and Pavletić, L. and Penil, P. and Perennes, C. and Persic, M. and Moroni, P.G.P. and Prandini, E. and Priyadarshi, C. and Puljak, I. and Rhode, W. and Ribó, M. and Rico, J. and Righi, C. and Rugliancich, A. and Saha, L. and Sahakyan, N. and Saito, T. and Sakurai, S. and Satalecka, K. and Saturni, F.G. and Schleicher, B. and Schmidt, K. and Schweizer, T. and Sitarek, J. and Šnidarić, I. and Sobczynska, D. and Spolon, A. and Stamerra, A. and Strom, D. and Strzys, M. and Suda, Y. and Surić, T. and Takahashi, M. and Tavecchio, F. and Temnikov, P. and Terzić, T. and Teshima, M. and Tosti, L. and Truzzi, S. and Tutone, A. and Ubach, S. and Van Scherpenberg, J. and Vanzo, G. and Vazquez Acosta, M. and Ventura, S. and Verguilov, V. and Vigorito, C.F. and Vitale, V. and Vovk, I. and Will, M. and Wunderlich, C. and Zarić, D. and Adams, C.B. and Benbow, W. and Brill, A. and Capasso, M. and Christiansen, J.L. and Chromey, A.J. and Daniel, M.K. and Errando, M. and Farrell, K.A. and Feng, Q. and Finley, J.P. and Fortson, L. and Furniss, A. and Gent, A. and Giuri, C. and Hassan, T. and Hervet, O. and Holder, J. and Hughes, G. and Humensky, T.B. and Jin, W. and Kaaret, P. and Kertzman, M. and Kieda, D. and Kumar, S. and Lang, M.J. and Lundy, M. and Maier, G. and Moriarty, P. and Mukherjee, R. and Nieto, D. and Nievas-Rosillo, M. and O'Brien, S. and Ong, R.A. and Otte, A.N. and Patel, S. and Pfrang, K. and Pohl, M. and Prado, R.R. and Pueschel, E. and Quinn, J. and Ragan, K. and Reynolds, P.T. and Ribeiro, D. and Richards, G.T. and Roache, E. and Rulten, C. and Ryan, J.L. and Santander, M. and Sembroski, G.H. and Shang, R. and Weinstein, A. and Williams, D.A. and Williamson, T.J. and Hirota, T. and Cui, L. and Niinuma, K. and Ro, H. and Sakai, N. and Sawada-Satoh, S. and Wajima, K. and Wang, N. and Liu, X. and Yonekura, Y.",
    journal = "The Astrophysical Journal Letters",
    year = "2021",
    volume = "911",
    number = "1",
    publisher = "American Astronomical Society",
    issn = "2041-8205, 2041-8213",
    doi = "10.3847/2041-8213/abef71",
    abstract = "In 2017, the Event Horizon Telescope (EHT) Collaboration succeeded in capturing the first direct image of the center of the M87 galaxy. The asymmetric ring morphology and size are consistent with theoretical expectations for a weakly accreting supermassive black hole of mass ∼6.5 × 109 M o˙. The EHTC also partnered with several international facilities in space and on the ground, to arrange an extensive, quasi-simultaneous multi-wavelength campaign. This Letter presents the results and analysis of this campaign, as well as the multi-wavelength data as a legacy data repository. We captured M87 in a historically low state, and the core flux dominates over HST-1 at high energies, making it possible to combine core flux constraints with the more spatially precise very long baseline interferometry data. We present the most complete simultaneous multi-wavelength spectrum of the active nucleus to date, and discuss the complexity and caveats of combining data from different spatial scales into one broadband spectrum. We apply two heuristic, isotropic leptonic single-zone models to provide insight into the basic source properties, but conclude that a structured jet is necessary to explain M87's spectrum. We can exclude that the simultaneous γ-ray emission is produced via inverse Compton emission in the same region producing the EHT mm-band emission, and further conclude that the γ-rays can only be produced in the inner jets (inward of HST-1) if there are strongly particle-dominated regions. Direct synchrotron emission from accelerated protons and secondaries cannot yet be excluded. © 2021. The Author(s). Published by the American Astronomical Society.."
}