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arXiv · 2501.05518

A multi-frequency study of sub-parsec jets with the Event Horizon Telescope

Jan Röder·Maciek Wielgus·Andrei P. Lobanov·Thomas P. Krichbaum·Dhanya G. Nair·Sang-Sung Lee·Eduardo Ros·Vincent L. Fish·Lindy Blackburn·Chi-kwan Chan·Sara Issaoun·Michael Janssen·Michael D. Johnson·Sheperd S. Doeleman·Geoffrey C. Bower·Geoffrey B. Crew·Remo P. J. Tilanus·Tuomas Savolainen·C. M. Violette Impellizzeri·Antxon Alberdi·Anne-Kathrin Baczko·José L. Gómez·Ru-Sen Lu·Georgios F. Paraschos·Efthalia Traianou·Ciriaco Goddi·Daewon Kim·Mikhail Lisakov·Yuri Y. Kovalev·Petr A. Voitsik·Kirill V. Sokolovsky·Kazunori Akiyama·Ezequiel Albentosa-Ruíz·Walter Alef·Juan Carlos Algaba·Richard Anantua·Keiichi Asada·Rebecca Azulay·Uwe Bach·David Ball·Mislav Baloković·Bidisha Bandyopadhyay·John Barrett·Michi Bauböck·Bradford A. Benson·Dan Bintley·Raymond Blundell·Katherine L. Bouman·Michael Bremer·Christiaan D. Brinkerink·Roger Brissenden·Silke Britzen·Avery E. Broderick·Dominique Broguiere·Thomas Bronzwaer·Sandra Bustamante·Do-Young Byun·John E. Carlstrom·Chiara Ceccobello·Andrew Chael·Dominic O. Chang·Koushik Chatterjee·Shami Chatterjee·Ming-Tang Chen·Yongjun Chen·Xiaopeng Cheng·Ilje Cho·Pierre Christian·Nicholas S. Conroy·John E. Conway·James M. Cordes·Thomas M. Crawford·Alejandro Cruz-Osorio·Yuzhu Cui·Brandon Curd·Rohan Dahale·Jordy Davelaar·Mariafelicia De Laurentis·Roger Deane·Jessica Dempsey·Gregory Desvignes·Jason Dexter·Vedant Dhruv·Indu K. Dihingia·Sean Taylor Dougall·Sergio A. Dzib·Ralph P. Eatough·Razieh Emami·Heino Falcke·Joseph Farah·Edward Fomalont·H. Alyson Ford·Marianna Foschi·Raquel Fraga-Encinas·William T. Freeman·Per Friberg·Christian M. Fromm·Antonio Fuentes·Peter Galison·Charles F. Gammie
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Abstract

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.

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Jan Röder, Maciek Wielgus, Andrei P. Lobanov, Thomas P. Krichbaum, Dhanya G. Nair, Sang-Sung Lee, Eduardo Ros, Vincent L. Fish, Lindy Blackburn, Chi-kwan Chan, Sara Issaoun, Michael Janssen, Michael D. Johnson, Sheperd S. Doeleman, Geoffrey C. Bower, Geoffrey B. Crew, Remo P. J. Tilanus, Tuomas Savolainen, C. M. Violette Impellizzeri, Antxon Alberdi, Anne-Kathrin Baczko, José L. Gómez, Ru-Sen Lu, Georgios F. Paraschos, Efthalia Traianou, Ciriaco Goddi, Daewon Kim, Mikhail Lisakov, Yuri Y. Kovalev, Petr A. Voitsik, Kirill V. Sokolovsky, Kazunori Akiyama, Ezequiel Albentosa-Ruíz, Walter Alef, Juan Carlos Algaba, Richard Anantua, Keiichi Asada, Rebecca Azulay, Uwe Bach, David Ball, Mislav Baloković, Bidisha Bandyopadhyay, John Barrett, Michi Bauböck, Bradford A. Benson, Dan Bintley, Raymond Blundell, Katherine L. Bouman, Michael Bremer, Christiaan D. Brinkerink, Roger Brissenden, Silke Britzen, Avery E. Broderick, Dominique Broguiere, Thomas Bronzwaer, Sandra Bustamante, Do-Young Byun, John E. Carlstrom, Chiara Ceccobello, Andrew Chael, Dominic O. Chang, Koushik Chatterjee, Shami Chatterjee, Ming-Tang Chen, Yongjun Chen, Xiaopeng Cheng, Ilje Cho, Pierre Christian, Nicholas S. Conroy, John E. Conway, James M. Cordes, Thomas M. Crawford, Alejandro Cruz-Osorio, Yuzhu Cui, Brandon Curd, Rohan Dahale, Jordy Davelaar, Mariafelicia De Laurentis, Roger Deane, Jessica Dempsey, Gregory Desvignes, Jason Dexter, Vedant Dhruv, Indu K. Dihingia, Sean Taylor Dougall, Sergio A. Dzib, Ralph P. Eatough, Razieh Emami, Heino Falcke, Joseph Farah, Edward Fomalont, H. Alyson Ford, Marianna Foschi, Raquel Fraga-Encinas, William T. Freeman, Per Friberg, Christian M. Fromm, Antonio Fuentes, Peter Galison, Charles F. Gammie. 2025-01-09. A multi-frequency study of sub-parsec jets with the Event Horizon Telescope. https://doi.org/10.1051/0004-6361%2F202452600

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