A multi-frequency study of sub-parsec jets with the Event Horizon Telescope
Creators: name: Röder, Jan
name: Wielgus, Maciek
name: Lobanov, Andrei P.
name: Krichbaum, Thomas P.
name: Nair, Dhanya G.
name: Lee, Sang-Sung
name: Ros, Eduardo
name: Fish, Vincent L.
name: Blackburn, Lindy
name: Chan, Chi-kwan
name: Issaoun, Sara
name: Janssen, Michael
name: Johnson, Michael D.
name: Doeleman, Sheperd S.
name: Bower, Geoffrey C.
name: Crew, Geoffrey B.
name: Tilanus, Remo P. J.
name: Savolainen, Tuomas
name: Impellizzeri, C. M. Violette
name: Alberdi, Antxon
name: Baczko, Anne-Kathrin
name: Gómez, José L.
name: Lu, Ru-Sen
name: Paraschos, Georgios F.
name: Traianou, Efthalia
name: Goddi, Ciriaco
name: Kim, Daewon
name: Lisakov, Mikhail
name: Kovalev, Yuri Y.
name: Voitsik, Petr A.
name: Sokolovsky, Kirill V.
name: Akiyama, Kazunori
name: Albentosa-Ruíz, Ezequiel
name: Alef, Walter
name: Algaba, Juan Carlos
name: Anantua, Richard
name: Asada, Keiichi
name: Azulay, Rebecca
name: Bach, Uwe
name: Ball, David
name: Baloković, Mislav
name: Bandyopadhyay, Bidisha
name: Barrett, John
name: Bauböck, Michi
name: Benson, Bradford A.
name: Bintley, Dan
name: Blundell, Raymond
name: Bouman, Katherine L.
name: Bremer, Michael
name: Brinkerink, Christiaan D.
name: Brissenden, Roger
name: Britzen, Silke
name: Broderick, Avery E.
name: Broguiere, Dominique
name: Bronzwaer, Thomas
name: Bustamante, Sandra
name: Byun, Do-Young
name: Carlstrom, John E.
name: Ceccobello, Chiara
name: Chael, Andrew
name: Chang, Dominic O.
name: Chatterjee, Koushik
name: Chatterjee, Shami
name: Chen, Ming-Tang
name: Chen, Yongjun
name: Cheng, Xiaopeng
name: Cho, Ilje
name: Christian, Pierre
name: Conroy, Nicholas S.
name: Conway, John E.
name: Cordes, James M.
name: Crawford, Thomas M.
name: Cruz-Osorio, Alejandro
name: Cui, Yuzhu
name: Curd, Brandon
name: Dahale, Rohan
name: Davelaar, Jordy
name: De Laurentis, Mariafelicia
name: Deane, Roger
name: Dempsey, Jessica
name: Desvignes, Gregory
name: Dexter, Jason
name: Dhruv, Vedant
name: Dihingia, Indu K.
name: Dougall, Sean Taylor
name: Dzib, Sergio A.
name: Eatough, Ralph P.
name: Emami, Razieh
name: Falcke, Heino
name: Farah, Joseph
name: Fomalont, Edward
name: Ford, H. Alyson
name: Foschi, Marianna
name: Fraga-Encinas, Raquel
name: Freeman, William T.
name: Friberg, Per
name: Fromm, Christian M.
name: Fuentes, Antonio
name: Galison, Peter
name: Gammie, Charles F.
name: García, Roberto
name: Gentaz, Olivier
name: Georgiev, Boris
name: Gold, Roman
name: Gómez-Ruiz, Arturo I.
name: Gu, Minfeng
name: Gurwell, Mark
name: Hada, Kazuhiro
name: Haggard, Daryl
name: Haworth, Kari
name: Hecht, Michael H.
name: Hesper, Ronald
name: Heumann, Dirk
name: Ho, Luis C.
name: Ho, Paul
name: Honma, Mareki
name: Huang, Chih-Wei L.
name: Huang, Lei
name: Hughes, David H.
name: Ikeda, Shiro
name: Inoue, Makoto
name: James, David J.
name: Jannuzi, Buell T.
name: Jeter, Britton
name: Jiang, Wu
name: Jiménez-Rosales, Alejandra
name: Jorstad, Svetlana
name: Joshi, Abhishek V.
name: Jung, Taehyun
name: Karami, Mansour
name: Karuppusamy, Ramesh
name: Kawashima, Tomohisa
name: Keating, Garrett K.
name: Kettenis, Mark
name: Kim, Dong-Jin
name: Kim, Jae-Young
name: Kim, Jongsoo
name: Kim, Junhan
name: Kino, Motoki
name: Koay, Jun Yi
name: Kocherlakota, Prashant
name: Kofuji, Yutaro
name: Koyama, Shoko
name: Kramer, Carsten
name: Kramer, Joana A.
name: Kramer, Michael
name: Kuo, Cheng-Yu
name: La Bella, Noemi
name: Lauer, Tod R.
name: Lee, Daeyoung
name: Leung, Po Kin
name: Levis, Aviad
name: Li, Zhiyuan
name: Lico, Rocco
name: Lindahl, Greg
name: Lindqvist, Michael
name: Liu, Jun
name: Liu, Kuo
name: Liuzzo, Elisabetta
name: Lo, Wen-Ping
name: Loinard, Laurent
name: Lonsdale, Colin J.
name: Lowitz, Amy E.
name: MacDonald, Nicholas R.
name: Mao, Jirong
name: Marchili, Nicola
name: Markoff, Sera
name: Marrone, Daniel P.
name: Marscher, Alan P.
name: Martí-Vidal, Iván
name: Matsushita, Satoki
name: Matthews, Lynn D.
name: Medeiros, Lia
name: Menten, Karl M.
name: Michalik, Daniel
name: Mizuno, Izumi
name: Mizuno, Yosuke
name: Moran, James M.
name: Moriyama, Kotaro
name: Moscibrodzka, Monika
name: Mulaudzi, Wanga
name: Müller, Cornelia
name: Müller, Hendrik
name: Mus, Alejandro
name: Musoke, Gibwa
name: Myserlis, Ioannis
name: Nadolski, Andrew
name: Nagai, Hiroshi
name: Nagar, Neil M.
name: Nakamura, Masanori
name: Narayanan, Gopal
name: Natarajan, Iniyan
name: Nathanail, Antonios
name: Fuentes, Santiago Navarro
name: Neilsen, Joey
name: Neri, Roberto
name: Ni, Chunchong
name: Noutsos, Aristeidis
name: Nowak, Michael A.
name: Oh, Junghwan
name: Okino, Hiroki
name: Sánchez, Héctor R. Olivares
name: Ortiz-León, Gisela N.
name: Oyama, Tomoaki
name: özel, Feryal
name: Palumbo, Daniel C. M.
name: Park, Jongho
name: Parsons, Harriet
name: Patel, Nimesh
name: Pen, Ue-Li
name: Pesce, Dominic W.
name: Piétu, Vincent
name: Plambeck, Richard
name: PopStefanija, Aleksandar
name: Porth, Oliver
name: Pötzl, Felix M.
name: Prather, Ben
name: Preciado-López, Jorge A.
name: Principe, Giacomo
name: Psaltis, Dimitrios
name: Pu, Hung-Yi
name: Ramakrishnan, Venkatessh
name: Rao, Ramprasad
name: Rawlings, Mark G.
name: Ricarte, Angelo
name: Ripperda, Bart
name: Roelofs, Freek
name: Rogers, Alan
name: Romero-Cañizales, Cristina
name: Roshanineshat, Arash
name: Rottmann, Helge
name: Roy, Alan L.
name: Ruiz, Ignacio
name: Ruszczyk, Chet
name: Rygl, Kazi L. J.
name: Sánchez, Salvador
name: Sánchez-Argüelles, David
name: Sánchez-Portal, Miguel
name: Sasada, Mahito
name: Satapathy, Kaushik
name: Schloerb, F. Peter
name: Schonfeld, Jonathan
name: Schuster, Karl-Friedrich
name: Shao, Lijing
name: Shen, Zhiqiang
name: Small, Des
name: Sohn, Bong Won
name: SooHoo, Jason
name: Salas, León David Sosapanta
name: Souccar, Kamal
name: Stanway, Joshua S.
name: Sun, He
name: Tazaki, Fumie
name: Tetarenko, Alexandra J.
name: Tiede, Paul
name: Titus, Michael
name: Torne, Pablo
name: Toscano, Teresa
name: Trent, Tyler
name: Trippe, Sascha
name: Turk, Matthew
name: van Bemmel, Ilse
name: van Langevelde, Huib J.
name: van Rossum, Daniel R.
name: Vos, Jesse
name: Wagner, Jan
name: Ward-Thompson, Derek
name: Wardle, John
name: Washington, Jasmin E.
name: Weintroub, Jonathan
name: Wharton, Robert
name: Wiik, Kaj
name: Witzel, Gunther
name: Wondrak, Michael F.
name: Wong, George N.
name: Wu, Qingwen
name: Yadlapalli, Nitika
name: Yamaguchi, Paul
name: Yfantis, Aristomenis
name: Yoon, Doosoo
name: Young, André
name: Young, Ken
name: Younsi, Ziri
name: Yu, Wei
name: Yuan, Feng
name: Yuan, Ye-Fei
name: Zensus, J. Anton
name: Zhang, Shuo
name: Zhao, Guang-Yao
name: Zhao, Shan-Shan
Publisher: name: arXiv
Year: 2025
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: The 2017 observing campaign of the Event Horizon Telescope (EHT) delivered the first very long baseline interferometry (VLBI) images at the observing frequency of 230 GHz, leading to a number of unique studies on black holes and relativistic jets from active galactic nuclei (AGN). In total, eighteen sources were observed: the main science targets, Sgr A* and M87 along with various calibrators. We investigated the morphology of the sixteen AGN in the EHT 2017 data set, focusing on the properties of the VLBI cores: size, flux density, and brightness temperature. We studied their dependence on the observing frequency in order to compare it with the Blandford-Königl (BK) jet model. We modeled the source structure of seven AGN in the EHT 2017 data set using linearly polarized circular Gaussian components and collected results for the other nine AGN from dedicated EHT publications, complemented by lower frequency data in the 2-86 GHz range. Then, we studied the dependences of the VLBI core flux density, size, and brightness temperature on the frequency measured in the AGN host frame. We compared the observations with the BK jet model and estimated the magnetic field strength dependence on the distance from the central black hole. Our results indicate a deviation from the standard BK model, particularly in the decrease of the brightness temperature with the observing frequency. Either bulk acceleration of the jet material, energy transfer from the magnetic field to the particles, or both are required to explain the observations.