Broadband multi-wavelength properties of M87 during the 2018 EHT campaign including a very high energy flaring episode

Creators: Algaba, J. C.¹; Baloković, M.^{2, 3}; Chandra, S.^{4, 5}; Cheong, W.-Y.^{6, 7}; Cui, Y.-Z.⁸; D'Ammando, F.⁹; Falcone, A. D.¹⁰; Ford, N. M.^{11, 12}; Giroletti, M.⁹; Goddi, C.^{13, 14}; Gurwell, M. A.¹⁵; Hada, K.^{16, 17, 18}; Haggard, D.^{11, 19}; Jorstad, S.²⁰; Kaur, A.²¹; Kawashima, T.²²; Kerby, S.²¹; Kim, J.-Y.^{6, 23}; Kino, M.^{24, 25}; Kravchenko, E. V.⁹; Lee, S.-S.⁶; Lu, R.-S.^{26, 27, 23}; Markoff, S.^{28, 29}; Michail, J.^{30, 31, 15}; Neilsen, J.³²; Nowak, M. A.³³; Principe, G.^{34, 35, 9}; Ramakrishnan, V.^{36, 37}; Ripperda, B.^{38, 39}; Sasada, M.⁴⁰; Savchenko, S. S.; Sheridan, C.³²; Akiyama, K.^{41, 24, 42}; Alberdi, A.⁴³; Alef, W.²³; Anantua, R.^{42, 15, 44}; Asada, K.⁴⁵; Azulay, R.^{46, 47, 23}; Bach, U.²³; Baczko, A.-K.^{48, 23}; Ball, D.⁴⁹; Bandyopadhyay, B.⁵⁰; Barrett, J.⁴¹; Bauböck, M.⁵¹; Benson, B. A.^{52, 53}; Bintley, D.^{54, 55}; lackburn, L.^{42, 15}; Blundell, R.¹⁵; Bouman, K. L.⁵⁶; Bower, G. C.^{57, 58}; Boyce, H.^{59, 60}; Bremer, M.⁶¹; Brissenden, R.^{42, 15}; Britzen, S.²³; Broderick, A. E.^{62, 63, 64}; Broguiere, D.⁶¹; Bronzwaer, T.¹³; Bustamante, S.⁶⁵; Carlstrom, J. E.^{66, 53, 67, 68}; Chael, A.⁶⁹; Chan, C.-k.^{49, 70, 71}; Chang, D. O.^{42, 15}; Chatterjee, K.^{42, 15}; Chatterjee, S.⁷²; Chen, M.-T.⁵⁷; Chen, Y.^{26, 27}; Cheng, X.⁶; Cho, I.^{43, 6, 73}; Christian, P.⁷⁴; Conroy, N. S.^{75, 15}; Conway, J. E.⁴⁸; Crawford, T. M.^{53, 66}; Crew, G. B.⁴¹; Cruz-Osorio, A.^{76, 77}; Dahale, R.⁴³; Davelaar, J.^{78, 38, 13}; De Laurentis, M.^{79, 80}; Deane, R.^{81, 82, 83}; Dempsey, J.^{54, 55, 84}; Desvignes, G.^{23, 85}; Dexter, J.⁸⁶; Dhruv, V.⁵¹; Dihingia, I. K.⁸⁷; Doeleman, S. S.^{42, 15}; Dzib, S. A.^{61, 23}; Eatough, R. P.^{88, 23}; Emami, R.¹⁵; Falcke, H.¹³; Farah, J.^{89, 90}; Fish, V. L.⁴¹; Fomalont, E.⁹¹; Ford, H. A.⁴⁹; Foschi, M.⁴³; Fraga-Encinas, R.¹³; Freeman, W. T.^{92, 93}; Friberg, P.^{54, 55}; Fromm, C. M.^{94, 77, 23}; Fuentes, A.⁴³; Galison, P.^{42, 95, 96}; Gammie, C. F.^{51, 75, 97}; García, R.⁶¹; Gentaz, O.⁶¹; Georgiev, B.⁴⁹; Gold, R.⁹⁸; Gómez-Ruiz, A. I.^{99, 100}; Gómez, J. L.⁴³; Gu, M.^{26, 101}; Hesper, R.¹⁰²; Heumann, D.⁴⁹; Ho, L. C.^{103, 104}; Ho, P.^{45, 55, 54}; Honma, M.^{16, 17, 105}; Huang, C.-W. L.⁴⁵; Huang, L.^{26, 101}; Hughes, D. H.⁹⁹; Ikeda, S.^{24, 106, 107, 108}; Impellizzeri, C. M. V.^{109, 91}; Inoue, M.⁴⁵; Issaoun, S.¹⁵; James, D. J.^{110, 111}; Jannuzi, B. T.⁴⁹; Janssen, M.^{13, 23}; Jeter, B.⁴⁵; Jiang, W.²⁶; Jiménez-Rosales, A.¹³; Johnson, M. D.^{42, 15}; Jones, A. C.⁵³; Joshi, A. V.⁵¹; Jung, T.^{6, 7}; Karuppusamy, R.²³; Keating, G. K.¹⁵; Kettenis, M.¹¹²; Kim, D.-J.⁴¹; Kim, J.⁶; Kim, J.¹¹³; Koay, J. Y.⁴⁵; Kocherlakota, P.⁷⁷; Kofuji, Y.^{16, 105}; Koch, P. M.⁴⁵; Koyama, S.^{114, 45}; Kramer, C.⁶¹; Kramer, J. A.²³; Kramer, M.²³; Krichbaum, T. P.²³; Kuo, C.-Y.^{115, 45}; La Bella, N.¹³; Levis, A.⁵⁶; Li, Z.^{116, 117}; Lico, R.^{118, 43}; Lindahl, G.¹⁵; Lindqvist, M.⁴⁸; Lisakov, M.²³; Liu, J.²³; Liu, K.²³; Liuzzo, E.¹¹⁹; Lo, W.-P.^{45, 120}; Lobanov, A. P.²³; Loinard, L.¹²¹; Lonsdale, C. J.⁴¹; Lowitz, A. E.⁴⁹; MacDonald, N. R.²³; Mao, J.^{122, 123, 124}; Marchili, N.^{119, 23}; Marrone, D. P.⁴⁹; Marscher, A. P.²⁰; Martí-Vidal, I.^{46, 47}; Matsushita, S.⁴⁵; Matthews, L. D.⁴¹; Medeiros, L.³⁹; Menten, K. M.²³; Mizuno, I.^{54, 55}; Mizuno, Y.^{87, 125, 77}; Montgomery, J.^{60, 53}; Moran, J. M.^{42, 15}; Moriyama, K.^{77, 16}; Moscibrodzka, M.¹³; Mulaudzi, W.²⁸; Müller, C.^{23, 13}; Müller, H.²³; Mus, A.^{46, 47}; Musoke, G.^{28, 13}; Myserlis, I.¹²⁶; Nagai, H.^{24, 17}; Nagar, N. M.⁵⁰; Nair, D. G.⁵⁰; Nakamura, M.^{127, 45}; Narayanan, G.⁶⁵; Natarajan, I.^{15, 42}; Nathanail, A.^{124, 128, 77}; Navarro Fuentes, S.¹²⁶; Ni, C.^{63, 64, 62}; Oh, J.¹¹²; Okino, H.^{16, 105}; Olivares, H.¹³; Oyama, T.¹⁶; Özel, F.¹²⁸; Palumbo, D. C. M.^{42, 15}; Filippos Paraschos, G.²³; Park, J.¹²⁹; Parsons, H.^{54, 55}; Patel, N.¹⁵; Pen, U.-L.^{45, 62, 130, 131, 132}; Pesce, D. W.^{15, 42}; Piétu, V.⁶¹; PopStefanija, A.⁶⁵; Porth, O.^{28, 77}; Prather, B.⁵¹; Psaltis, D.¹²⁸; Pu, H.-Y.^{133, 134, 45}; Rao, R.¹⁵; Rawlings, M. G.^{135, 54, 55}; Raymond, A. W.^{42, 15}; Rezzolla, L.^{77, 136, 137}; Ricarte, A.^{42, 15}; Roelofs, F.^{15, 42, 13}; Romero-Cañizales, C.⁴⁵; Ros, E.²³; Roshanineshat, A.⁴⁹; Rottmann, H.²³; Roy, A. L.²³; Ruiz, I.¹²⁶; Ruszczyk, C.⁴¹; Rygl, K. L. J.¹¹⁹; Sánchez, S.¹²⁶; Sánchez-Argüelles, D.^{99, 100}; Sánchez-Portal, M.¹²⁶; Satapathy, K.⁴⁹; Savolainen, T.^{138, 37, 23}; Schloerb, F. P.⁶⁵; Schonfeld, J.¹⁵; Schuster, K.-F.⁶¹; Shao, L.^{104, 23}; Shen, Z.^{26, 27}; Small, D.¹¹²; Sohn, B. W.^{6, 7, 73}; SooHoo, J.⁴¹; Sosapanta Salas, L. D.²⁸; Souccar, K.⁶⁵; Stanway, J. S.¹³⁹; Sun, H.^{140, 141}; Tazaki, F.¹⁴²; Tetarenko, A. J.¹⁴³; Tiede, P.^{15, 42}; Tilanus, R. P. J.^{49, 13, 109, 144}; Titus, M.⁴¹; Toma, K.^{145, 146}; Torne, P.^{126, 23}; Toscano, T.⁴³; Traianou, E.^{43, 23}; Trent, T.⁴⁹; Trippe, S.¹⁴⁷; Turk, M.⁷⁵; van Bemmel, I.¹¹²; van Langevelde, H. J.^{112, 109, 148}; van Rossum, D. R.¹³; Vos, J.¹³; Wagner, J.²³; Ward-Thompson, D.¹⁴⁹; Wardle, J.¹⁴⁹; Washington, J. E.⁴⁹; Weintroub, J.^{42, 15}; Wharton, R.²³; Wielgus, M.²³; Wiik, K.¹⁵⁰; Witzel, G.²³; Wondrak, M. F.^{13, 151}; Wong, G. N.^{152, 69}; Wu, Q.¹⁵³; Yadlapalli, N.⁵⁶; Yamaguchi, P.¹⁵; Yfantis, A.¹³; Yoon, D.²⁸; Young, A.¹³; Younsi, Z.^{154, 77}; Yu, W.¹⁵; Yuan, F.¹⁵⁵; Yuan, Y.-F.¹⁵⁶; Zensus, J. A.²³; Zhang, S.¹⁵⁷; Zhao, G.-Y.^{43, 23}; Zhao, S.-S.²⁶; Bellazzini, R.¹⁵⁸; Berenji, B.¹⁵⁹; Bissaldi, E.^{160, 161}; Blandford, R. D.¹⁶²; Bonino, R.^{163, 164}; Bruel, P.¹⁶⁵; Cameron, R. A.¹⁶²; Caraveo, P. A.¹⁶⁶; Cavazzuti, E.¹⁶⁷; Cheung, C. C.¹⁶⁸; Ciprini, S.^{169, 170}; Cristarella Orestano, P.^{171, 172}; Cutini, S.¹⁷²; Di Lalla, N.¹⁶²; Dinesh, A.¹⁷³; Di Venere, L.¹⁶¹; Domínguez, A.¹⁷³; Fegan, S. J.¹⁶⁵; Franckowiak, A.¹⁷⁴; Fukazawa, Y.¹⁷⁵; Fusco, P.^{160, 161}; Gargano, F.¹⁶¹; Gasbarra, C.^{169, 176}; Germani, S.¹⁷¹; Giliberti, M.^{161, 160}; Grenier, I. A.¹⁷⁷; Hays, E.¹⁷⁸; Horan, D.¹⁶⁵; Kuss, M.¹⁵⁸; Larsson, S.^{179, 180}; Liodakis, I.¹⁸¹; Longo, F.^{34, 35}; Loparco, F.^{160, 161}; Lovellette, M. N.¹⁸²; Maldera, S.¹⁶³; Mazziotta, M. N.¹⁶¹; Mereu, I.^{172, 171}; Michelson, P. F.¹⁶²; Mirabal, N.^{178, 183}; Mizuno, T.¹⁸⁴; Monzani, M. E.^{162, 185}; Morselli, A.¹⁶⁹; Negro, M.¹⁸⁶; Omodei, N.¹⁶²; Orlando, E.^{35, 34, 162}; Persic, M.^{35, 187}; Rainò, S.^{160, 161}; Rani, B.^{178, 183}; Reimer, A.¹⁸⁸; Reimer, O.¹⁸⁸; Sánchez-Conde, M.^{189, 190}; Saz Parkinson, P. M.¹⁹¹; Sgrò, C.¹⁵⁸; Siskind, E. J.¹⁹²; Spinelli, P.^{160, 161}; Suson, D. J.¹⁹³; Tajima, H.^{194, 195}; Torres, D. F.^{196, 197}; Zaharijas, G.¹⁹⁸; Aharonian, F.^{199, 200, 201}; Ait Benkhali, F.²⁰²; Aschersleben, J.²⁰³; Ashkar, H.²⁰⁴; Backes, M.^{205, 4}; Barbosa Martins, V.^{206, 174}; Batzofin, R.²⁰⁷; Becherini, Y.^{208, 209}; Berge, D.^{206, 210}; Böttcher, M.⁴; Boisson, C.²¹¹; Bolmont, J.²¹²; de Bony de Lavergne, M.²¹³; Borowska, J.²¹⁰; Bouyahiaoui, M.²⁰⁰; Bradascio, F.²¹³; Brose, R.¹⁹⁹; Brown, A.²¹⁴; Bruno, B.²¹⁵; Bulik, T.²¹⁶; Burger-Scheidlin, C.¹⁹⁹; Casanova, S.²¹⁷; Cecil, R.²¹⁸; Celic, J.²¹⁵; Cerruti, M.²⁰⁸; Chand, T.⁴; Chen, A.²¹⁹; Chibueze, J.⁴; Chibueze, O.⁴; Cotter, G.²¹⁴; Damascene Mbarubucyeye, J.²⁰⁶; Devin, J.²¹⁹; Djuvsland, J.²⁰⁰; Dmytriiev, A.⁴; Einecke, S.²²⁰; Ernenwein, J.-P.²²¹; Feijen, K.²⁰⁸; Fontaine, G.²⁰⁴; Funk, S.²¹⁵; Gabici, S.²⁰⁸; Glawion, D.²¹⁵; Glicenstein, J. F.²¹³; Goswami, P.²⁰⁸; Grolleron, G.²¹²; Haerer, L.²⁰⁰; Heß, B.²²²; Holch, T. L.²⁰⁶; Holler, M.²²³; Horns, D.²¹⁸; Huang, Zhiqiu²⁰⁰; Jamrozy, M.²²⁴; Jankowsky, F.²⁰²; Jung-Richardt, I.²¹⁵; Kasai, E.²⁰⁵; Katarzyński, K.²²⁵; Khatoon, R.⁴; Khélifi, B.²⁰⁸; Kluźniak, W.²²⁶; Komin, Nu.²¹⁹; Kosack, K.²¹³; Kundu, A.⁴; Lang, R. G.²¹⁵; Le Stum, S.²²¹; Leitl, F.²¹⁵; Lemière, A.²⁰⁸; Lemoine-Goumard, M.²²⁷; Lenain, J.-P.²¹²; Leuschner, F.²²²; Luashvili, A.²¹¹; Mackey, J.¹⁹⁹; Malyshev, D.²²²; Martí-Devesa, G.²²³; Marx, R.²⁰²; Meyer, M.²²⁸; Mitchell, A.²¹⁵; Moderski, R.²²⁶; Moghadam, M. O.²⁰⁷; Mohrmann, L.²⁰⁰; Montanari, A.²⁰²; Moulin, E.²¹³; de Naurois, M.²⁰⁴; Niemiec, J.²¹⁷; O'Brien, P.²²⁹; Ohm, S.²⁰⁶; de Ona Wilhelmi, E.²⁰⁶; Ostrowski, M.²²⁴; Panny, S.²²³; Panter, M.²⁰⁰; Pensec, U.²¹²; Pita, S.²⁰⁸; Pühlhofer, G.²²²; Quirrenbach, A.²⁰²; Ravikularaman, S.^{208, 200}; Reimer, A.²²³; Reimer, O.²²³; Reville, B.²⁰⁰; Reis, I.²¹³; Ren, H.²⁰⁰; Rieger, F.²⁰⁰; Roellinghoff, G.²¹⁵; Rudak, B.²²⁶; Ruiz-Velasco, E.²⁰⁰; Sabri, K.²³⁰; Sahakian, V.²⁰¹; Salzmann, H.²²²; Santangelo, A.²²³; Sasaki, M.²¹⁵; Schäfer, J.²¹⁵; Schüssler, F.²¹³; Schutte, H. M.⁴; Shapopi, J. N. S.²⁰⁵; Sharma, A.²⁰⁸; Sol, H.²¹¹; Spencer, S.²¹⁵; Stawarz, Ł.²²⁴; Steppa, C.²⁰⁷; Streil, K.²¹⁵; Suzuki, H.²³¹; Takahashi, T.²³²; Tanaka, T.²³¹; Taylor, A. M.²⁰⁶; Terrier, R.²⁰⁸; Tluczykont, M.²¹⁸; Tsirou, M.²⁰⁶; van Eldik, C.²¹⁵; Vecchi, M.²⁰³; Wach, T.²¹⁵; Wagner, S. J.²⁰²; Wierzcholska, A.²¹⁷; Zacharias, M.^{202, 4}; Zdziarski, A. A.²²⁶; Zech, A.²¹¹; Żywucka, N.⁴; Abe, S.²³³; Abhir, J.²³⁴; Abhishek, A.²³⁵; Acciari, V. A.²³⁶; Aguasca-Cabot, A.²³⁷; Agudo, I.²³⁸; Aniello, T.²³⁹; Ansoldi, S.^{240, 241}; Antonelli, L. A.²³⁹; Arbet Engels, A.²⁴²; Arcaro, C.²⁴³; Artero, M.²³⁶; Asano, K.²³³; Babić, A.²⁴⁴; Barres de Almeida, U.²⁴⁵; Barrio, J. A.²⁴⁶; Batković, I.²⁴³; Bautista, A.²⁴²; Baxter, J.²³³; Becerra González, J.²⁴⁷; Bednarek, W.²⁴⁸; Bernardini, E.²⁴³; Bernete, J.²⁴⁹; Berti, A.²⁴²; Besenrieder, J.²⁴²; Bigongiari, C.²³⁹; Biland, A.²³⁴; Blanch, O.²³⁶; Bonnoli, G.²³⁹; Bošnjak, Ž.²⁴⁴; Bronzini, E.²³⁹; Burelli, I.²⁴⁰; Busetto, G.²⁴³; Campoy-Ordaz, A.²⁵⁰; Carosi, A.²³⁹; Carosi, R.²⁵¹; Carretero-Castrillo, M.²³⁷; Castro-Tirado, A. J.²³⁸; Cerasole, D.²⁵²; Ceribella, G.²⁴²; Chai, Y.²³³; Cifuentes, A.²⁴⁹; Colombo, E.²³⁶; Contreras, J. L.²⁴⁶; Cortina, J.²⁴⁹; Covino, S.²³⁹; D'Amico, G.²⁵³; D'Elia, V.²³⁹; Da Vela, P.²³⁹; Dazzi, F.²³⁹; De Angelis, A.²⁴³; De Lotto, B.²⁴⁰; de Menezes, R.²⁵⁴; Delfino, M.^{236, 255}; Delgado, J.^{236, 255}; Delgado Mendez, C.²⁴⁹; Di Pierro, F.²⁵⁴; Di Tria, R.²⁵²; Di Venere, L.²⁵²; Dominis Prester, D.²⁵⁶; Donini, A.²³⁹; Dorner, D.²⁵⁷; Doro, M.²⁴³; Elsaesser, D.²⁵⁸; Escudero, J.²³⁸; Fariña, L.²³⁶; Fattorini, A.²⁵⁸; Foffano, L.²³⁹; Font, L.²⁵⁰; Fröse, S.²⁵⁸; Fukami, S.²³⁴; Fukazawa, Y.²⁵⁹; García López, R. J.²⁴⁷; Garczarczyk, M.²⁰⁶; Gasparyan, S.²⁶⁰; Gaug, M.²⁵⁰; Giesbrecht Paiva, J. G.²⁴⁵; Giglietto, N.²⁵²; Giordano, F.²⁵²; Gliwny, P.²⁴⁸; Godinović, N.²⁶¹; Gradetzke, T.²⁵⁸; Grau, R.²³⁶; Green, D.²⁴²; Green, J. G.²⁴²; Günther, P.²⁵⁷; Hadasch, D.²³³; Hahn, A.²⁴²; Hassan, T.²⁴⁹; Heckmann, L.²⁴²; Herrera Llorente, J.²⁴⁷; Hrupec, D.²⁶²; Imazawa, R.²⁵⁹; Ishio, K.²⁴⁸; Jiménez Martínez, I.²⁴²; Jormanainen, J.²⁶³; Kayanoki, T.²⁵⁹; Kerszberg, D.²³⁶; Kluge, G. W.^{253, 264}; Kobayashi, Y.²³³; Kouch, P. M.²⁶³; Kubo, H.²³³; Kushida, J.²⁶⁵; Láinez, M.²⁴⁶; Lamastra, A.²³⁹; Leone, F.²³⁹; Lindfors, E.²⁶³; Lombardi, S.²³⁹; López-Coto, R.²³⁸; López-Moya, M.²⁴⁶; López-Oramas, A.²⁴⁷; Loporchio, S.²⁵²; Lorini, A.²³⁵; Lyard, E.²⁶⁶; Machado de Oliveira Fraga, B.²⁴⁵; Majumdar, P.²⁶⁷; Makariev, M.²⁶⁸; Maneva, G.²⁶⁸; Manganaro, M.²⁵⁶; Mangano, S.²⁴⁹; Mannheim, K.²⁵⁷; Mariotti, M.²⁴³; Martínez, M.²³⁶; Martínez-Chicharro, M.²⁴⁹; Mas-Aguilar, A.²⁴⁶; Mazin, D.^{233, 242}; Menchiari, S.²³⁵; Mender, S.²⁵⁸; Miceli, D.²⁴³; Miener, T.²⁴⁶; Miranda, J. M.²³⁵; Mirzoyan, R.²⁴²; Molero González, M.²⁴⁷; Molina, E.²⁴⁷; Mondal, H. A.²⁶⁷; Moralejo, A.²³⁶; Morcuende, D.²³⁸; Nakamori, T.²⁶⁹; Nanci, C.²³⁹; Neustroev, V.²⁷⁰; Nickel, L.²⁵⁸; Nievas Rosillo, M.²⁴⁷; Nigro, C.²³⁶; Nikolić, L.²³⁵; Nilsson, K.²⁶³; Nishijima, K.²⁶⁵; Njoh Ekoume, T.²³⁶; Noda, K.²⁷⁰; Nozaki, S.²⁴²; Ohtani, Y.²³³; Okumura, A.²⁷¹; Otero-Santos, J.²³⁸; Paiano, S.²³⁹; Paneque, D.²⁴²; Paoletti, R.²³⁵; Paredes, J. M.²³⁷; Peresano, M.²⁴²; Persic, M.^{240, 272}; Pihet, M.²⁴³; Pirola, G.²⁴²; Podobnik, F.²³⁵; Prada Moroni, P. G.²⁵¹; Prandini, E.²⁴³; Priyadarshi, C.²³⁶; Ribó, M.²³⁷; Rico, J.²³⁶; Righi, C.²³⁹; Sahakyan, N.²⁶⁰; Saito, T.²³³; Saturni, F. G.²³⁹; Schmidt, K.²⁵⁸; Schmuckermaier, F.²⁴²; Schubert, J. L.²⁵⁸; Schweizer, T.²⁴²; Sciaccaluga, A.²³⁹; Silvestri, G.²⁴³; Sitarek, J.²⁴⁸; Sliusar, V.²⁶⁶; Sobczynska, D.²⁴⁸; Spolon, A.²⁴³; Stamerra, A.²³⁹; Strišković, J.²⁶²; Strom, D.²⁴²; Strzys, M.²³³; Suda, Y.²⁵⁹; Suutarinen, S.²⁶³; Tajima, H.²⁷¹; Takahashi, M.²⁷¹; Takeishi, R.²³³; Tavecchio, F.²³⁹; Temnikov, P.²⁶⁸; Terauchi, K.²⁷³; Terzić, T.²⁵⁶; Teshima, M.^{242, 233}; Truzzi, S.²³⁵; Tutone, A.²³⁹; Ubach, S.²⁶²; van Scherpenberg, J.²⁴²; Vazquez Acosta, M.²⁴⁷; Ventura, S.²³⁵; Verna, G.²³⁵; Viale, I.²⁴³; Vigorito, C. F.²⁵⁴; Vitale, V.²⁷⁴; Vovk, I.²³³; Walter, R.²⁶⁶; Will, M.²⁴²; Wunderlich, C.²³⁵; Yamamoto, T.²⁷⁵; Acharyya, A.²⁷⁶; Adams, C. B.²⁷⁷; Bangale, P.²⁷⁸; Bartkoske, J. T.²⁷⁹; Benbow, W.¹⁵; Christiansen, J. L.²⁸⁰; Duerr, A.²⁷⁹; Errando, M.²⁸¹; Feng, Q.²⁷⁹; Foote, G. M.²⁷⁸; Fortson, L.²⁸²; Furniss, A.²⁸³; Hanlon, W.¹⁵; Hervet, O.²⁸⁴; Hinrichs, C. E.^{15, 285}; Holder, J.²⁷⁸; Humensky, T. B.^{286, 287}; Jin, W.^{288, 289}; Johnson, M. N.²⁸⁴; Kaaret, P.²⁹⁰; Kertzman, M.²⁹¹; Kieda, D.²⁷⁹; Kleiner, T. K.²⁰⁶; Korzoun, N.²⁷⁸; Krennrich, F.²⁹²; Kumar, S.²⁸⁶; Lang, M. J.²⁹³; Lundy, M.²⁹⁴; Maier, G.²⁰⁶; McGrath, C. E.²⁹⁵; Millard, M. J.²⁹⁰; Mooney, C. L.²⁷⁸; Moriarty, P.²⁹³; Mukherjee, R.²⁹⁶; Ning, W.²⁸⁸; O'Brien, S.^{294, 297}; Ong, R. A.²⁸⁸; Pohl, M.^{298, 206}; Pueschel, E.²⁹⁹; Quinn, J.²⁹⁵; Ragan, K.²⁹⁴; Reynolds, P. T.³⁰⁰; Ribeiro, D.²⁸²; Roache, E.¹⁵; Ryan, J. L.²⁸⁸; Sadeh, I.²⁰⁶; Saha, L.¹⁵; Santander, M.²⁸⁹; Sembroski, G. H.³⁰¹; Shang, R.²⁹⁶; Splettstoesser, M.²⁸⁴; Talluri, A. K.²⁸²; Tucci, J. V.³⁰²; Valverde, J.^{303, 287}; Vassiliev, V. V.²⁸⁸; Williams, D. A.²⁸⁴; Wong, S. L.²⁹⁴; Chen, Z.^{26, 304}; Cui, L.^{305, 27}; Hirota, T.^{16, 17}; Li, B.^{26, 304}; Li, G.³⁰⁵; Liu, Q.^{26, 304}; Liu, X.^{305, 27}; Liu, Z.³⁰⁵; Ma, J.³⁰⁵; Niinuma, K.^{306, 307}; Ro, H.⁶; Sakai, N.³⁰⁸; Sawada-Satoh, S.³⁰⁹; Wajima, K.^{6, 7}; Wang, J.^{6, 304}; Wang, N.^{305, 27}; Xia, B.^{26, 304}; Yan, H.³⁰⁵; Yonekura, Y.³¹⁰; Zhang, H.³⁰⁵; Zhao, R.^{26, 304}; Zhong, W.^{26, 304}; EAVN Collaboration; MAGIC Collaboration; H.E.S.S. Collaboration; Event Horizon Telescope Collaboration

1. Department of Physics, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia
2. Yale Center for Astronomy & Astrophysics, 52 Hillhouse Avenue, New Haven, CT, 06511, USA
3. Department of Physics, Yale University, P.O. Box 2018120, New Haven, CT, 06520, USA
4. Centre for Space Research, North-West University, Potchefstroom, 2520, South Africa
5. Physical Research Laboratory, Ahmedabad, Gujarat, 380009, India
6. Korea Astronomy and Space Science Institute, Daedeok-daero 776, Yuseong-gu, Daejeon, 34055, Republic of Korea
7. University of Science and Technology, Gajeong-ro 217, Yuseong-gu, Daejeon, 34113, Republic of Korea
8. Research Center for Astronomical Computing, Zhejiang Lab, Hangzhou, 311100, People's Republic of China
9. INAF Istituto di Radioastronomia, Via P. Gobetti, 101, I-40129, Bologna, Italy
10. Davey Laboratory, Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA, 16802, USA
11. Department of Physics, McGill University, 3600 University Street, Montréal, QC, H3A 2T8, Canada
12. Trottier Space Institute at McGill, 3550 University Street, Montréal, QC, H3A 2A7, Canada
13. Department of Astrophysics, Institute for Mathematics, Astrophysics and Particle Physics (IMAPP), Radboud University, P.O. Box 9010, 6500 GL, Nijmegen, The Netherlands
14. Leiden Observatory–Allegro, Leiden University, P.O. Box 9513, 2300 RA, Leiden, The Netherlands
15. Center for Astrophysics | Harvard & Smithsonian, Cambridge, MA, 02138, USA
16. Mizusawa VLBI Observatory, National Astronomical Observatory of Japan, 2-12 Hoshigaoka, Mizusawa, Oshu, Iwate, 023-0861, Japan
17. Astronomical Science Program, The Graduate University for Advanced Studies (SOKENDAI), 2-21-1 Osawa, Mitaka, Tokyo, 181-8588, Japan
18. Graduate School of Science, Nagoya City University, Yamanohata 1, Mizuho-cho, Mizuho-ku, Nagoya, 467-8501, Aichi, Japan
19. McGill Space Institute, McGill University, 3550 University Street, Montréal, QC, H3A 2A7, Canada
20. Institute for Astrophysical Research, Boston University, 725 Commonwealth Ave., Boston, 02215, MA, USA
21. Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA, 16802, USA
22. Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8582, Japan
23. Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121, Bonn, Germany
24. National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo, 181-8588, Japan
25. Kogakuin University of Technology & Engineering, Academic Support Center, 2665-1 Nakano, Hachioji, Tokyo, 192-0015, Japan
26. Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai, 200030, People's Republic of China
27. Key Laboratory of Radio Astronomy, Chinese Academy of Sciences, Nanjing, 210008, People's Republic of China
28. API–Anton Pannekoek Institute for Astronomy, University of Amsterdam, Science Park 904, 1098, XH, Amsterdam, The Netherlands
29. GRAPPA–Gravitation and AstroParticle Physics Amsterdam, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
30. Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Rd, Evanston, IL, 60208, USA
31. Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Northwestern University, 1800 Sherman Ave, Evanston, IL, 60201, USA
32. Department of Physics, Villanova University, 800 E. Lancaster Avenue, Villanova, PA, 19085, USA
33. Physics Department, Washington University, CB 1105, St Louis, MO, 63130, USA
34. Dipartimento di Fisica, Università di Trieste, I-34127, Trieste, Italy
35. Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127, Trieste, Italy
36. Finnish Centre for Astronomy with ESO, FI-20014, University of Turku, Finland
37. Aalto University Metsähovi Radio Observatory, Metsähovintie 114, FI-02540, Kylmälä, Finland
38. Center for Computational Astrophysics, Flatiron Institute, 162 Fifth Avenue, New York, NY, 10010, USA
39. Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ, 08544, USA
40. Hiroshima Astrophysical Science Center, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan
41. Massachusetts Institute of Technology Haystack Observatory, 99 Millstone Road, Westford, MA, 01886, USA
42. Black Hole Initiative at Harvard University, 20 Garden Street, Cambridge, MA, 02138, USA
43. Instituto de Astrofísica de Andalucía-CSIC, Glorieta de la Astronomía s/n, E-18008, Granada, Spain
44. Department of Physics & Astronomy, The University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, 78249, USA
45. Institute of Astronomy and Astrophysics, Academia Sinica, 11F of Astronomy-Mathematics Building, AS/NTU No. 1, Sec. 4, Roosevelt Rd., Taipei, 10617, Taiwan R.O.C.
46. Departament d'Astronomia i Astrofísica, Universitat de Valéncia, C. Dr. Moliner 50, E-46100, Burjassot, Valéncia, Spain
47. Observatori Astronómic, Universitat de València, C. Catedrático José Beltrán 2, E-46980, Paterna, València, Spain
48. Department of Space, Earth and Environment, Chalmers University of Technology, Onsala Space Observatory, SE-43992, Onsala, Sweden
49. Steward Observatory and Department of Astronomy, University of Arizona, 933 N. Cherry Ave., Tucson, AZ, 85721, USA
50. Astronomy Department, Universidad de Concepción, Casilla 160-C, Concepción, Chile
51. Department of Physics, University of Illinois, 1110 West Green Street, Urbana, IL, 61801, USA
52. Fermi National Accelerator Laboratory, MS209, P.O. Box 500, Batavia, IL, 60510, USA
53. Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL, 60637, USA
54. East Asian Observatory, 660 N. A'ohoku Place, Hilo, HI, 96720, USA
55. James Clerk Maxwell Telescope (JCMT), 660 N. A'ohoku Place, Hilo, HI, 96720, USA
56. California Institute of Technology
57. Institute of Astronomy and Astrophysics, Academia Sinica, 645 N. A'ohoku Place, Hilo, HI, 96720, USA
58. Department of Physics and Astronomy, University of Hawaii at Manoa, 2505 Correa Road, Honolulu, HI, 96822, USA
59. Department of Physics, McGill University, 3600 rue University, Montréal, QC, H3A 2T8, Canada
60. Trottier Space Institute at McGill, 3550 rue University, Montréal, QC, H3A 2A7, Canada
61. Institut de Radioastronomie Millimétrique (IRAM), 300 rue de la Piscine, F-38406, Saint Martin d'Hères, France
62. Perimeter Institute for Theoretical Physics, 31 Caroline Street North, Waterloo, ON, N2L 2Y5, Canada
63. Department of Physics and Astronomy, University of Waterloo, 200 University Avenue West, Waterloo, ON, N2L 3G1, Canada
64. Waterloo Centre for Astrophysics, University of Waterloo, Waterloo, ON, N2L 3G1, Canada
65. Department of Astronomy, University of Massachusetts, Amherst, MA, 01003, USA
66. Kavli Institute for Cosmological Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL, 60637, USA
67. Department of Physics, University of Chicago, 5720 South Ellis Avenue, Chicago, IL, 60637, USA
68. Enrico Fermi Institute, University of Chicago, 5640 South Ellis Avenue, Chicago, IL, 60637, USA
69. Princeton Gravity Initiative, Jadwin Hall, Princeton University, Princeton, NJ, 08544, USA
70. Data Science Institute, University of Arizona, 1230 N. Cherry Ave., Tucson, AZ, 85721, USA
71. Program in Applied Mathematics, University of Arizona, 617 N. Santa Rita, Tucson, AZ, 85721, USA
72. Cornell Center for Astrophysics and Planetary Science, Cornell University, Ithaca, NY, 14853, USA
73. Department of Astronomy, Yonsei University, Yonsei-ro 50, Seodaemun-gu, 03722, Seoul, Republic of Korea
74. Physics Department, Fairfield University, 1073 North Benson Road, Fairfield, CT, 06824, USA
75. Department of Astronomy, University of Illinois at Urbana-Champaign, 1002 West Green Street, Urbana, IL, 61801, USA
76. Instituto de Astronomía, Universidad Nacional Autónoma de México (UNAM), Apdo Postal 70-264, Ciudad de Mexico, Mexico
77. Institut für Theoretische Physik, Goethe-Universität Frankfurt, Max-von-Laue-Straße 1, D-60438, Frankfurt am Main, Germany
78. Department of Astronomy and Columbia Astrophysics Laboratory, Columbia University, 500 W. 120th Street, New York, NY, 10027, USA
79. Dipartimento di Fisica "E. Pancini", Università di Napoli "Federico II", Compl. Univ. di Monte S. Angelo, Edificio G, Via Cinthia, I-80126, Napoli, Italy
80. INFN Sez. di Napoli, Compl. Univ. di Monte S. Angelo, Edificio G, Via Cinthia, I-80126, Napoli, Italy
81. Wits Centre for Astrophysics, University of the Witwatersrand, 1 Jan Smuts Avenue, Braamfontein, Johannesburg, 2050, South Africa
82. Department of Physics, University of Pretoria, Hatfield, Pretoria, 0028, South Africa
83. Centre for Radio Astronomy Techniques and Technologies, Department of Physics and Electronics, Rhodes University, Makhanda, 6140, South Africa
84. ASTRON, Oude Hoogeveensedijk 4, 7991, PD, Dwingeloo, The Netherlands
85. LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université de Paris, 5 place Jules Janssen, F-92195, Meudon, France
86. JILA and Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO, 80309, USA
87. Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shengrong Road 520, Shanghai, 201210, People's Republic of China
88. National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing, 100101, PR China
89. Las Cumbres Observatory, 6740 Cortona Drive, Suite 102, Goleta, CA, 93117-5575, USA
90. Department of Physics, University of California, Santa Barbara, CA, 93106-9530, USA
91. National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA, 22903, USA
92. Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 32-D476, 77 Massachusetts Ave., Cambridge, MA, 02142, USA
93. Google Research, 355 Main St., Cambridge, MA, 02142, USA
94. Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Emil-Fischer-Str. 31, D-97074, Würzburg, Germany
95. Department of History of Science, Harvard University, Cambridge, MA, 02138, USA
96. Department of Physics, Harvard University, Cambridge, MA, 02138, USA
97. NCSA, University of Illinois, 1205 W. Clark St., Urbana, IL, 61801, USA
98. CP3-Origins, University of Southern Denmark, Campusvej 55, DK-5230, Odense M, Denmark
99. Instituto Nacional de Astrofísica, Óptica y Electrónica, Apartado Postal 51 y 216, 72000, Puebla Pue., Mexico
100. Consejo Nacional de Humanidades, Ciencia y Tecnología, Av. Insurgentes Sur 1582, 03940, Ciudad de México, Mexico
101. Key Laboratory for Research in Galaxies and Cosmology, Chinese Academy of Sciences, Shanghai, 200030, People's Republic of China
102. NOVA Sub-mm Instrumentation Group, Kapteyn Astronomical Institute, University of Groningen, Landleven 12, 9747 AD, Groningen, The Netherlands
103. Department of Astronomy, School of Physics, Peking University, Beijing, 100871, People's Republic of China
104. Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing, 100871, People's Republic of China
105. Department of Astronomy, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
106. The Institute of Statistical Mathematics, 10-3 Midori-cho, Tachikawa, Tokyo, 190-8562, Japan
107. Department of Statistical Science, The Graduate University for Advanced Studies (SOKENDAI), 10-3 Midori-cho, Tachikawa, Tokyo, 190-8562, Japan
108. Kavli Institute for the Physics and Mathematics of the Universe, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, 277-8583, Japan
109. Leiden Observatory, Leiden University, Postbus 2300, 9513, RA, Leiden, The Netherlands
110. ASTRAVEO LLC, PO Box 1668, Gloucester, MA, 01931, USA
111. Applied Materials Inc., 35 Dory Road, Gloucester, MA, 01930, USA
112. Joint Institute for VLBI ERIC (JIVE), Oude Hoogeveensedijk 4, 7991 PD, Dwingeloo, The Netherlands
113. Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
114. Graduate School of Science and Technology, Niigata University, 8050 Ikarashi 2-no-cho, Nishi-ku, Niigata, 950-2181, Japan
115. Physics Department, National Sun Yat-Sen University, No. 70, Lien-Hai Road, Kaosiung City, 80424, Taiwan, R.O.C.
116. School of Astronomy and Space Science, Nanjing University, Nanjing, 210023, People's Republic of China
117. Key Laboratory of Modern Astronomy and Astrophysics, Nanjing University, Nanjing, 210023, People's Republic of China
118. INAF-Istituto di Radioastronomia, Via P. Gobetti 101, I-40129, Bologna, Italy
119. INAF-Istituto di Radioastronomia & Italian ALMA Regional Centre, Via P. Gobetti 101, I-40129, Bologna, Italy
120. Department of Physics, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei, 10617, Taiwan, R.O.C
121. Instituto de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México, Morelia, 58089, Mexico
122. Yunnan Observatories, Chinese Academy of Sciences, 650011, Kunming, Yunnan Province, People's Republic of China
123. Center for Astronomical Mega-Science, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing, 100012, People's Republic of China
124. Astronomy Department, Universidad de Concepción, Casilla 160-C, Concepción, Chile; Research Center for Astronomy, Academy of Athens, Soranou Efessiou 4, 115 27, Athens, Greece
125. School of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, People's Republic of China
126. Institut de Radioastronomie Millimétrique (IRAM), Avenida Divina Pastora 7, Local 20, E-18012, Granada, Spain
127. National Institute of Technology, Hachinohe College, 16-1 Uwanotai, Tamonoki, Hachinohe City, Aomori, 039-1192, Japan
128. School of Physics, Georgia Institute of Technology, 837 State St NW, Atlanta, GA, 30332, USA
129. Department of Astronomy and Space Science, Kyung Hee University, 1732, Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do, 17104, Republic of Korea
130. Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St. George Street, Toronto, ON, M5S 3H8, Canada
131. Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON, M5S 3H4, Canada
132. Canadian Institute for Advanced Research, 180 Dundas St West, Toronto, ON, M5G 1Z8, Canada
133. Department of Physics, National Taiwan Normal University, No. 88, Sec. 4, Tingzhou Rd., Taipei, 116, Taiwan, R.O.C.
134. Center of Astronomy and Gravitation, National Taiwan Normal University, No. 88, Sec. 4, Tingzhou Road, Taipei, 116, Taiwan, R.O.C.
135. Gemini Observatory/NSF's NOIRLab, 670 N. Aòhōkū Place, Hilo, HI, 96720, USA
136. Frankfurt Institute for Advanced Studies, Ruth-Moufang-Strasse 1, D-60438, Frankfurt, Germany
137. School of Mathematics, Trinity College, Dublin 2, Ireland
138. Aalto University Department of Electronics and Nanoengineering, PL 15500, FI-00076, Aalto, Finland
139. Jeremiah Horrocks Institute, University of Central Lancashire, Preston, PR1 2HE, UK
140. National Biomedical Imaging Center, Peking University, Beijing, 100871, People's Republic of China
141. College of Future Technology, Peking University, Beijing, 100871, People's Republic of China
142. Tokyo Electron Technology Solutions Limited, 52 Matsunagane, Iwayado, Esashi, Oshu, Iwate, 023-1101, Japan
143. Department of Physics and Astronomy, University of Lethbridge, Lethbridge, Alberta, T1K 3M4, Canada
144. Netherlands Organisation for Scientific Research (NWO), Postbus 93138, 2509, AC, Den Haag, The Netherlands
145. Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, 980-8578, Japan
146. Astronomical Institute, Tohoku University, Sendai, 980-8578, Japan
147. Department of Physics and Astronomy, Seoul National University, Gwanak-gu, Seoul, 08826, Republic of Korea
148. University of New Mexico, Department of Physics and Astronomy, Albuquerque, NM, 87131, USA
149. Physics Department, Brandeis University, 415 South Street, Waltham, MA, 02453, USA
150. Tuorla Observatory, Department of Physics and Astronomy, University of Turku, Turku, Finland
151. Radboud Excellence Fellow of Radboud University, Nijmegen, The Netherlands
152. School of Natural Sciences, Institute for Advanced Study, 1 Einstein Drive, Princeton, NJ, 08540, USA
153. School of Physics, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, People's Republic of China
154. Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey, RH5 6NT, UK
155. Center for Astronomy and Astrophysics and Department of Physics, Fudan University, Shanghai, 200438, People's Republic of China
156. Astronomy Department, University of Science and Technology of China, Hefei, 230026, People's Republic of China
157. Department of Physics and Astronomy, Michigan State University, 567 Wilson Rd, East Lansing, MI, 48824, USA
158. Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127, Pisa, Italy
159. California State University, Los Angeles, Department of Physics and Astronomy, Los Angeles, CA, 90032, USA
160. Dipartimento di Fisica "M. Merlin" dell'Università e del Politecnico di Bari, via Amendola 173, I-70126, Bari, Italy
161. Istituto Nazionale di Fisica Nucleare, Sezione di Bari, I-70126, Bari, Italy
162. W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA, 94305, USA
163. Istituto Nazionale di Fisica Nucleare, Sezione di Torino, I-10125, Torino, Italy
164. Dipartimento di Fisica, Università degli Studi di Torino, I-10125, Torino, Italy
165. Laboratoire Leprince-Ringuet, CNRS/IN2P3, École polytechnique, Institut Polytechnique de Paris, 91120, Palaiseau, France
166. INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica Milano, Via E. Bassini 15, I-20133, Milano, Italy
167. Italian Space Agency, Via del Politecnico snc, 00133, Roma, Italy
168. Space Science Division, Naval Research Laboratory, Washington, DC, 20375-5352, USA
169. Istituto Nazionale di Fisica Nucleare, Sezione di Roma "Tor Vergata", I-00133, Roma, Italy
170. Space Science Data Center – Agenzia Spaziale Italiana, Via del Politecnico, snc, I-00133, Roma, Italy
171. Dipartimento di Fisica, Università degli Studi di Perugia, I-06123, Perugia, Italy
172. Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, I-06123, Perugia, Italy
173. Grupo de Altas Energías, Universidad Complutense de Madrid, E-28040, Madrid, Spain
174. Ruhr University Bochum, Faculty of Physics and Astronomy, Astronomical Institute (AIRUB), 44780, Bochum, Germany
175. Department of Physical Sciences, Hiroshima University, Higashi-Hiroshima, Hiroshima, 739-8526, Japan
176. Dipartimento di Fisica, Università di Roma "Tor Vergata", I-00133, Roma, Italy
177. Université Paris Cité, Université Paris-Saclay, CEA, CNRS, AIM, F-91191, Gif-sur-Yvette, France
178. NASA Goddard Space Flight Center, Greenbelt, MD, 20771, USA
179. Department of Physics, KTH Royal Institute of Technology, AlbaNova, SE-106 91, Stockholm, Sweden
180. The Oskar Klein Centre for Cosmoparticle Physics, AlbaNova, SE-106 91, Stockholm, Sweden
181. NASA Marshall Space Flight Center, Huntsville, AL, 35812, USA
182. The Aerospace Corporation, 14745 Lee Rd, Chantilly, VA, 20151, USA
183. Department of Physics and Center for Space Sciences and Technology, University of Maryland Baltimore County, Baltimore, MD, 21250, USA
184. Hiroshima Astrophysical Science Center, Hiroshima University, Higashi-Hiroshima, Hiroshima, 739-8526, Japan
185. Vatican Observatory, V-00120, Castel Gandolfo, Vatican City State
186. Department of physics and Astronomy, Louisiana State University, Baton Rouge, LA, 70803, USA
187. INAF-Astronomical Observatory of Padova, Vicolo dell'Osservatorio 5, I-35122, Padova, Italy
188. Institut für Astro- und Teilchenphysik, Leopold-Franzens-Universität Innsbruck, A-6020, Innsbruck, Austria
189. Instituto de Física Teórica UAM/CSIC, Universidad Autónoma de Madrid, E-28049, Madrid, Spain
190. Departamento de Física Teórica, Universidad Autónoma de Madrid, 28049, Madrid, Spain
191. Santa Cruz Institute for Particle Physics Department of Physics and Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA, 95064, USA
192. NYCB Real-Time Computing Inc., Lattingtown, NY, 11560-1025, USA
193. Purdue University Northwest, Hammond, IN, 46323, USA
194. Nagoya University, Institute for Space-Earth Environmental Research, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan
195. Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan
196. Institute of Space Sciences (ICE, CSIC), Campus UAB, Carrer de Magrans s/n, E-08193 Barcelona, Spain; and Institut d'Estudis Espacials de Catalunya (IEEC), E-08034, Barcelona, Spain
197. Instituci'o Catalana de Recerca i Estudis Avanccats (ICREA), E-08010, Barcelona, Spain
198. Center for Astrophysics and Cosmology, University of Nova Gorica, Nova Gorica, Slovenia
199. Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2, Ireland
200. Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117, Heidelberg, Germany
201. Yerevan State University, 1 Alek Manukyan St., Yerevan, 0025, Armenia
202. Landessternwarte, Universität Heidelberg, Königstuhl, D-69117, Heidelberg, Germany
203. Kapteyn Astronomical Institute, University of Groningen, Landleven 12, 9747 AD, Groningen, The Netherlands
204. Laboratoire Leprince-Ringuet, École Polytechnique, CNRS, Institut Polytechnique de Paris, F-91128, Palaiseau, France
205. University of Namibia, Department of Physics, Private Bag 13301, Windhoek, 10005, Namibia
206. Deutsches Elektronen-Synchrotron DESY, Platanenallee 6, 15738, Zeuthen, Germany
207. Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Strasse 24/25, D-14476, Potsdam, Germany
208. Université de Paris, CNRS, Astroparticule et Cosmologie, F-75013, Paris, France
209. Department of Physics and Electrical Engineering, Linnaeus University, 351 95, Växjö, Sweden
210. Institut für Physik, Humboldt-Universität zu Berlin, Newtonstr. 15, D-12489, Berlin, Germany
211. Laboratoire Univers et Théories, Observatoire de Paris, Université PSL, CNRS, Université Paris Cité, 5 Pl. Jules Janssen, 92190, Meudon, France
212. Sorbonne Université, CNRS/IN2P3, Laboratoire de Physique Nucléaire et de Hautes Energies, LPNHE, 4 place Jussieu, 75005, Paris, France
213. IRFU, CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette, France
214. University of Oxford, Department of Physics, Denys Wilkinson Building, Keble Road, Oxford, OX1 3RH, UK
215. Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen Centre for Astroparticle Physics, Nikolaus-Fiebiger-Str. 2, 91058, Erlangen, Germany
216. Astronomical Observatory, The University of Warsaw, Al. Ujazdowskie 4, 00-478, Warsaw, Poland
217. Instytut Fizyki Jdrowej PAN, ul. Radzikowskiego 152, 31-342, Kraków, Poland
218. Universität Hamburg, Institut für Experimentalphysik, Luruper Chaussee 149, D-22761, Hamburg, Germany
219. School of Physics, University of the Witwatersrand, 1 Jan Smuts Avenue, Braamfontein, Johannesburg, 2050, South Africa
220. School of Physical Sciences, University of Adelaide, Adelaide, 5005, Australia
221. Aix Marseille Université, CNRS/IN2P3, CPPM, Marseille, France
222. Institut für Astronomie und Astrophysik, Universität Tübingen, Sand 1, D-72076, Tübingen, Germany
223. Universität Innsbruck, Institut für Astro- und Teilchenphysik, Technikerstraße 25, 6020, Innsbruck, Austria
224. Obserwatorium Astronomiczne, Uniwersytet Jagielloński, ul. Orla 171, 30-244, Kraków, Poland
225. Institute of Astronomy, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, 87-100, Torun, Poland
226. Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, ul. Bartycka 18, 00-716, Warsaw, Poland
227. Université Bordeaux, CNRS, LP2I Bordeaux, UMR 5797, F-33170, Gradignan, France
228. University of Southern Denmark, DK-5230, Odense, Denmark
229. Department of Physics and Astronomy, The University of Leicester, University Road, Leicester, LE1 7RH, UK
230. Laboratoire Univers et Particules de Montpellier, Université Montpellier, CNRS/IN2P3, CC 72, Place Eugène Bataillon, F-34095, Montpellier Cedex 5, France
231. Department of Physics, Konan University, 8-9-1 Okamoto, Higashinada, Kobe, Hyogo, 658-8501, Japan
232. Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo Institutes for Advanced Study (UTIAS), The University of Tokyo, 5-1-5 Kashiwa-no-Ha, Kashiwa, Chiba, 277-8583, Japan
233. Japanese MAGIC Group: Institute for Cosmic Ray Research (ICRR), The University of Tokyo, Kashiwa, 277-8582, Chiba, Japan
234. ETH Zürich, CH-8093, Zürich, Switzerland
235. Università di Siena and INFN Pisa, I-53100, Siena, Italy
236. Institut de Física d'Altes Energies (IFAE), The Barcelona Institute of Science and Technology (BIST), E-08193, Bellaterra, (Barcelona), Spain
237. Universitat de Barcelona, ICCUB, IEEC-UB, E-08028, Barcelona, Spain
238. Instituto de Astrofísica de Andalucía-CSIC, Glorieta de la Astronomía s/n, 18008, Granada, Spain
239. National Institute for Astrophysics (INAF), I-00136, Rome, Italy
240. Università di Udine and INFN Trieste, I-33100, Udine, Italy
241. Also at International Center for Relativistic Astrophysics (ICRA), Rome, Italy
242. Max-Planck-Institut für Physik, D-85748, Garching, Germany
243. Università di Padova and INFN, I-35131, Padova, Italy
244. Croatian MAGIC Group: University of Zagreb, Faculty of Electrical Engineering and Computing (FER), 10000, Zagreb, Croatia
245. Centro Brasileiro de Pesquisas Físicas (CBPF), 22290-180, URCA, Rio de Janeiro, (RJ), Brazil
246. IPARCOS Institute and EMFTEL Department, Universidad Complutense de Madrid, E-28040, Madrid, Spain
247. Instituto de Astrofísica de Canarias and Dpto. de Astrofísica, Universidad de La Laguna, E-38200, La Laguna, Tenerife, Spain
248. University of Lodz, Faculty of Physics and Applied Informatics, Department of Astrophysics, 90-236, Lodz, Poland
249. Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, E-28040, Madrid, Spain
250. Departament de Física, and CERES-IEEC, Universitat Autònoma de Barcelona, E-08193, Bellaterra, Spain
251. Università di Pisa and INFN Pisa, I-56126, Pisa, Italy
252. INFN MAGIC Group: INFN Sezione di Bari and Dipartimento Interateneo di Fisica dell'Università e del Politecnico di Bari, I-70125, Bari, Italy
253. Department for Physics and Technology, University of Bergen, Bergen, Norway
254. INFN MAGIC Group: INFN Sezione di Torino and Università degli Studi di Torino, I-10125, Torino, Italy
255. Also at Port d'Informació Científica (PIC), E-08193, Bellaterra, (Barcelona), Spain
256. Croatian MAGIC Group: University of Rijeka, Faculty of Physics, 51000, Rijeka, Croatia
257. Universität Würzburg, D-97074, Würzburg, Germany
258. Technische Universität Dortmund, D-44221, Dortmund, Germany
259. Japanese MAGIC Group: Physics Program, Graduate School of Advanced Science and Engineering, Hiroshima University, 739-8526, Hiroshima, Japan
260. Armenian MAGIC Group: ICRANet-Armenia, 0019, Yerevan, Armenia
261. Croatian MAGIC Group: University of Split, Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture (FESB), 21000, Split, Croatia
262. Croatian MAGIC Group: Josip Juraj Strossmayer University of Osijek, Department of Physics, 31000, Osijek, Croatia
263. Finnish MAGIC Group: Finnish Centre for Astronomy with ESO, Department of Physics and Astronomy, University of Turku, FI-20014, Turku, Finland
264. Also at Department of Physics, University of Oslo, Oslo, Norway
265. Japanese MAGIC Group: Department of Physics, Tokai University, Hiratsuka, 259-1292, Kanagawa, Japan
266. University of Geneva, Chemin d'Ecogia 16, CH-1290, Versoix, Switzerland
267. Saha Institute of Nuclear Physics, A CI of Homi Bhabha National Institute, Kolkata, 700064, West Bengal, India
268. Inst. for Nucl. Research and Nucl. Energy, Bulgarian Academy of Sciences, BG-1784, Sofia, Bulgaria
269. Japanese MAGIC Group: Department of Physics, Yamagata University, Yamagata, 990-8560, Japan
270. Finnish MAGIC Group: Space Physics and Astronomy Research Unit, University of Oulu, FI-90014, Oulu, Finland
271. Japanese MAGIC Group: Institute for Space-Earth Environmental Research and Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University, 464-6801, Nagoya, Japan
272. Also at INAF Padova, I-35122, Padova, Italy
273. Japanese MAGIC Group: Department of Physics, Kyoto University, 606-8502, Kyoto, Japan
274. INFN MAGIC Group: INFN Roma Tor Vergata, I-00133, Roma, Italy
275. Japanese MAGIC Group: Department of Physics, Konan University, Kobe, Hyogo, 658-8501, Japan
276. CP3-Origins, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
277. Physics Department, Columbia University, New York, NY, 10027, USA
278. Department of Physics and Astronomy and the Bartol Research Institute, University of Delaware, Newark, DE, 19716, USA
279. Department of Physics and Astronomy, University of Utah, Salt Lake City, UT, 84112, USA
280. Physics Department, California Polytechnic State University, San Luis Obispo, CA, 94307, USA
281. Department of Physics, Washington University, St. Louis, MO, 63130, USA
282. School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, 55455, USA
283. Department of Physics, California State University – East Bay, Hayward, CA, 94542, USA
284. Santa Cruz Institute for Particle Physics and Department of Physics, University of California, Santa Cruz, CA, 95064, USA
285. Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, NH, 03755, USA
286. Department of Physics, University of Maryland, College Park, MD, USA
287. NASA GSFC, Greenbelt, MD, 20771, USA
288. Department of Physics and Astronomy, University of California, Los Angeles, CA, 90095, USA
289. Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL, 35487, USA
290. Department of Physics and Astronomy, University of Iowa, Van Allen Hall, Iowa City, IA, 52242, USA
291. Department of Physics and Astronomy, DePauw University, Greencastle, IN, 46135-0037, USA
292. Department of Physics and Astronomy, Iowa State University, Ames, IA, 50011, USA
293. School of Natural Sciences, University of Galway, University Road, Galway, H91 TK33, Ireland
294. Physics Department, McGill University, Montreal, QC, H3A 2T8, Canada
295. School of Physics, University College Dublin, Belfield, Dublin 4, Ireland
296. Department of Physics and Astronomy, Barnard College, Columbia University, NY, 10027, USA
297. Arthur B. McDonald Canadian Astroparticle Physics Research Institute, 64 Bader Lane, Queen's University, Kingston, ON, K7L 3N6, Canada
298. Institute of Physics and Astronomy, University of Potsdam, 14476, Potsdam-Golm, Germany
299. Fakultät für Physik & Astronomie, Ruhr-Universität Bochum, D-44780, Bochum, Germany
300. Department of Physical Sciences, Munster Technological University, Bishopstown, Cork, T12 P928, Ireland
301. Department of Physics and Astronomy, Purdue University, West Lafayette, IN, 47907, USA
302. Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, IN, 46202, USA
303. Department of Physics, University of Maryland, Baltimore County, Baltimore, MD, 21250, USA
304. Key Laboratory of Radio Astronomy and Technology, Chinese Academy of Sciences, A20 Datun Road, Chaoyang District, Beijing, 100101, PR China
305. Xinjiang Astronomical Observatory, Chinese Academy of Sciences, 150 Science 1-Street, Urumqi, 830011, PR China
306. Graduate School of Sciences and Technology for Innovation, Yamaguchi University, J-753-8512, Yamaguchi, Japan
307. The Research Institute for Time Studies, Yamaguchi University, J-753-0841, Yamaguchi, Japan
308. National Astronomical Research Institute of Thailand (NARIT), 260 Moo 4, T. Donkaew, A. Maerim, 50180, Chiangmai, Thailand
309. Graduate School of Science, Osaka Metropolitan University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8531, Japan
310. Center for Astronomy, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki, 310-8512, Japan

Abstract

Context. The nearby elliptical galaxy M87 contains one of only two supermassive black holes whose emission surrounding the event horizon has been imaged by the Event Horizon Telescope (EHT). In 2018, more than two dozen multi-wavelength (MWL) facilities (from radio to γ-ray energies) took part in the second M87 EHT campaign.

Aims. The goal of this extensive MWL campaign was to better understand the physics of the accreting black hole M87*, the relationship between the inflow and inner jets, and the high-energy particle acceleration. Understanding the complex astrophysics is also a necessary first step towards performing further tests of general relativity.

Methods. The MWL campaign took place in April 2018, overlapping with the EHT M87* observations. We present a new, contemporaneous spectral energy distribution (SED) ranging from radio to very high-energy (VHE) γ-rays as well as details of the individual observations and light curves. We also conducted phenomenological modelling to investigate the basic source properties.

Results. We present the first VHE γ-ray flare from M87 detected since 2010. The flux above 350 GeV more than doubled within a period of ≈36 hours. We find that the X-ray flux is enhanced by about a factor of two compared to 2017, while the radio and millimetre core fluxes are consistent between 2017 and 2018. We detect evidence for a monotonically increasing jet position angle that corresponds to variations in the bright spot of the EHT image.

Conclusions. Our results show the value of continued MWL monitoring together with precision imaging for addressing the origins of high-energy particle acceleration. While we cannot currently pinpoint the precise location where such acceleration takes place, the new VHE γ-ray flare already presents a challenge to simple one-zone leptonic emission model approaches, and it emphasises the need for combined image and spectral modelling.

Copyright and License

© The Authors 2024. Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Acknowledgement

The full acknowledgements are available in Appendix A.

Data Availability

Tables from Appendix C (from C.1 to C.15) are available at the CDS via anonymous ftp to cdsarc.cds.unistra.fr (130.79.128.5) or via https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/692/A140

Data products presented in this paper are available for download through the EHT Collaboration Data Webpage (https://eventhorizontelescope.org/for-astronomers/data), or directly from the CyVerse repository. The repository contains the following data products:

Broadband spectrum table with frequency, flux density, its uncertainty, and instrument index (format: DAT).
Sampled posterior distributions of the SED broadband spectral model (A-PL) described in Sect. 4.2 (format: DAT).
Sampled posterior distributions of the SED broadband spectral model (A-BPL) described in Sect. 4.3 (format: DAT).
Sampled posterior distributions of the SED broadband spectral model (B) described in Sect. 4.3 (format: DAT).

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