A multifrequency study of sub-parsec jets with the Event Horizon Telescope
Journal article, 2025
Context. 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, including the main science targets, Sgr A∗ and M87, and various calibrators. Sixteen sources were AGN. Aims.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-Konigl (BK) jet model. In particular, we aimed to study the signatures of jet acceleration and magnetic energy conversion. Methods. We modeled the source structure of seven AGN in the EHT 2017 data set using linearly polarized circular Gaussian components (1749+096, 1055+018, BL Lac, J0132-1654, J0006-0623, CTA102, and 3C 454.3) and collected results for the other nine AGN from dedicated EHT publications, complemented by lower frequency data in the 2-86 GHz range. Combining these data into a multifrequency EHT+ data set, we studied the dependences of the VLBI core component flux density, size, and brightness temperature on the frequency measured in the AGN host frame (and hence on the distance from the central black hole), characterizing them with power law fits. We compared the observations with the BK jet model and estimated the magnetic field strength dependence on the distance from the central black hole. Results. Our observations spanning event horizon to parsec scales indicate a deviation from the standard BK model, particularly in the decrease of the brightness temperature with the observing frequency. Only some of the discrepancies may be alleviated by tweaking the model parameters or the jet collimation profile. Either bulk acceleration of the jet material, energy transfer from the magnetic field to the particles, or both are required to explain the observations. For our sample, we estimate a general radial dependence of the Doppler factor δ ∝ r≤0.5. This interpretation is consistent with a magnetically accelerated sub-parsec jet. We also estimate a steep decrease of the magnetic field strength with radius B ∝ r-3, hinting at jet acceleration or efficient magnetic energy dissipation.
Techniques: interferometric
Galaxies: jets
Quasars: supermassive black holes
Galaxies: nuclei
Quasars: general
Galaxies: active
Author
J. Röder
Max Planck Society
M. Wielgus
Max Planck Society
A. P. Lobanov
Max Planck Society
T.P. Krichbaum
Max Planck Society
Dhanya G. Nair
Max Planck Society
Sang Sung Lee
Korea Astronomy and Space Science Institute
Eduardo Ros
Max Planck Society
V. Fish
Massachusetts Institute of Technology (MIT)
Lindy Blackburn
Harvard University
Chi Kwan Chan
University of Arizona
S. Issaoun
Harvard-Smithsonian Center for Astrophysics
Michael Janssen
Max Planck Society
Michael D. Johnson
Harvard University
S. Doeleman
Harvard University
G. C. Bower
Academia Sinica
G. Crew
Massachusetts Institute of Technology (MIT)
R. P. J. Tilanus
University of Arizona
T. Savolainen
Max Planck Society
C. M. V. Impellizzeri
Leiden University
Antxon Alberdi
Spanish National Research Council (CSIC)
A. K. Baczko
Max Planck Society
J. L. Gomez
Spanish National Research Council (CSIC)
R.S. Lu
Max Planck Society
Georgios Filippos Paraschos
Max Planck Society
E. Traianou
Max Planck Society
C. Goddi
University of Sao Paulo (USP)
Daewon Kim
Max Planck Society
Mikhail Lisakov
Pontificia Universidad Católica de Valparaíso
Yuri Y. Kovalev
Max Planck Society
Petr A. Voitsik
Independent researcher
K. V. Sokolovsky
University of Illinois
Kazunori Akiyama
Massachusetts Institute of Technology (MIT)
E. Albentosa-Ruiz
Universitat de Valencia
Walter Alef
Max Planck Society
Juan-Carlos Algaba
University of Malaya
Richard Anantua
Harvard University
K. Asada
Academia Sinica
R. Azulay
Max Planck Society
U. Bach
Max Planck Society
David Ball
University of Arizona
Mislav Baloković
Yale University
Bidisha Bandyopadhyay
University of Concepcion
John Barrett
Massachusetts Institute of Technology (MIT)
M. Bauböck
The Grainger College of Engineering
Bradford A. Benson
Fermi National Accelerator Laboratory
Dan Bintley
East Asian Observatory
R. Blundell
Harvard-Smithsonian Center for Astrophysics
K. L. Bouman
California Institute of Technology (Caltech)
M. Bremer
Institut de Radioastronomie Millimétrique (IRAM)
C. D. Brinkerink
Radboud University
Roger Brissenden
Harvard University
Silke Britzen
Max Planck Society
Avery E. Broderick
Perimeter Institute for Theoretical Physics
D. Broguière
Institut de Radioastronomie Millimétrique (IRAM)
Thomas Bronzwaer
Radboud University
Sandra Bustamente
University of Massachusetts
Do Young Byun
Korea Astronomy and Space Science Institute
J. E. Carlstrom
University of Chicago
Chiara Ceccobello
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
A. Chael
Princeton University
Dominic O. Chang
Harvard University
Koushik Chatterjee
Harvard University
S. Chatterjee
Cornell University
Ming Tang Chen
Academia Sinica
Yongjun Chen
Chinese Academy of Sciences
X. P. Cheng
Korea Astronomy and Space Science Institute
I. Cho
Spanish National Research Council (CSIC)
Pierre Christian
Fairfield University
Nicholas S. Conroy
Harvard-Smithsonian Center for Astrophysics
John Conway
Chalmers, Space, Earth and Environment, Onsala Space Observatory
James M. Cordes
Cornell University
Thomas M. Crawford
University of Chicago
Alejandro Cruz-Osorio
Universidad Nacional Autónoma de México
Yuzhu Cui
Zhejiang Lab
Brandon Curd
Harvard University
Rohan Dahale
Spanish National Research Council (CSIC)
Jordy Davelaar
Radboud University
Mariafelicia De Laurentis
Goethe University Frankfurt
R. P. Deane
University of Witwatersrand
Jessica Dempsey
East Asian Observatory
Gregory Desvignes
Max Planck Society
Jason Dexter
JILA
Vedant Dhruv
The Grainger College of Engineering
Indu K. Dihingia
Shanghai Jiao Tong University
Sean Dougall
University of Arizona
Sergio A. Dzib
Max Planck Society
Ralph P. Eatough
Max Planck Society
Razieh Emami
Harvard-Smithsonian Center for Astrophysics
H.D. Falcke
Radboud University
Joseph R. Farah
Las Cumbres Observatory Global Telescope Network
E. Fomalont
National Radio Astronomy Observatory
H. Alyson Ford
University of Arizona
Marianna Foschi
Spanish National Research Council (CSIC)
R. Fraga-Encinas
Radboud University
W.T. Freeman
Massachusetts Institute of Technology (MIT)
P. Friberg
East Asian Observatory
Christian M. Fromm
Max Planck Society
Antonio Fuentes
Spanish National Research Council (CSIC)
Peter Galison
Harvard University
Charles F. Gammie
University of Illinois
Roberto Garcia
Institut de Radioastronomie Millimétrique (IRAM)
Olivier Gentaz
Institut de Radioastronomie Millimétrique (IRAM)
Boris Georgiev
University of Arizona
R. Gold
Heidelberg University
Arturo I. Gómez-Ruiz
National Institute of Astrophysics, Optics and Electronics
Minfeng Gu
Chinese Academy of Sciences
M. Gurwell
Harvard-Smithsonian Center for Astrophysics
K. Hada
National Astronomical Observatory of Japan
Daryl Haggard
McGill University
Kari Haworth
Harvard-Smithsonian Center for Astrophysics
Michael H. Hecht
Massachusetts Institute of Technology (MIT)
R. Hesper
University of Groningen
Dirk Heumann
University of Arizona
Luis C. Ho
Beijing University of Technology
P. T. P. Ho
Academia Sinica
M. Honma
National Astronomical Observatory of Japan
Chih Wei L. Huang
Academia Sinica
Lei Huang
Chinese Academy of Sciences
D. Hughes
National Institute of Astrophysics, Optics and Electronics
Shiro Ikeda
National Astronomical Observatory of Japan
Makoto Inoue
Academia Sinica
David J. James
ASTRAVEO
Buell T. Jannuzi
University of Arizona
Britton Jeter
Academia Sinica
Wu Jiang
Chinese Academy of Sciences
Alejandra Jimenez-Rosales
Radboud University
S.G. Jorstad
Boston University
Abhishek V. Joshi
The Grainger College of Engineering
Taehyun Jung
Korea Astronomy and Space Science Institute
Mansour Karami
Perimeter Institute for Theoretical Physics
R. Karuppusamy
Max Planck Society
Tomohisa Kawashima
University of Tokyo
G. Keating
Harvard-Smithsonian Center for Astrophysics
M. M. Kettenis
Joint Institute for VLBI in Europe (JIVE)
Dong-Jin Kim
Max Planck Society
Jae-Young Kim
Max Planck Society
Jongsoo Kim
Korea Astronomy and Space Science Institute
Junhan Kim
Korea Advanced Institute of Science and Technology (KAIST)
M. Kino
National Astronomical Observatory of Japan
Tomohisa Kawashima
Academia Sinica
Prashant Kocherlakota
Harvard University
Yutaro Kofuji
National Astronomical Observatory of Japan
Shoko Koyama
Academia Sinica
C. Kramer
Institut de Radioastronomie Millimétrique (IRAM)
Joana A. Kramer
Max Planck Society
M. Kramer
Max Planck Society
Cheng Yu Kuo
Academia Sinica
Michael Lindqvist
Radboud University
Tod R. Lauer
National Optical Astronomy Observatory
Daeyoung Lee
The Grainger College of Engineering
Po Kin Leung
Chinese University of Hong Kong
Aviad Levis
California Institute of Technology (Caltech)
Zhiyuan Li
Nanjing University
R. Lico
Spanish National Research Council (CSIC)
Greg Lindahl
Harvard-Smithsonian Center for Astrophysics
Michael Lindqvist
Chalmers, Space, Earth and Environment, Onsala Space Observatory
Jun Liu
Max Planck Society
Kuo Liu
Max Planck Society
Elisabetta Liuzzo
Istituto di Radioastronomia
Wen-Ping Lo
Academia Sinica
L. Loinard
Harvard University
Colin Lonsdale
Massachusetts Institute of Technology (MIT)
Amy E. Lowitz
University of Arizona
N. R. Macdonald
Max Planck Society
Jirong Mao
Yunnan Observatories
Nicola Marchili
Max Planck Society
S. Markoff
Anton Pannekoek Institute for Astronomy
D. P. Marrone
University of Arizona
A. Marscher
Boston University
Ivan Marti-Vidal
Universitat de Valencia
S. Matsushita
Academia Sinica
Lynn D. Matthews
Massachusetts Institute of Technology (MIT)
Lia Medeiros
Einstein Fellow
K. Menten
Max Planck Society
Daniel Michalik
European Space Agency (ESA)
Izumi Mizuno
East Asian Observatory
Yosuke Mizuno
Goethe University Frankfurt
James M. Moran
Harvard University
Kotaro Moriyama
Massachusetts Institute of Technology (MIT)
M. Mościbrodzka
Radboud University
Wanga Mulaudzi
Anton Pannekoek Institute for Astronomy
C. Müller
Max Planck Society
Hendrik Müller
National Radio Astronomy Observatory
A. Mus
University of Cagliari
Gibwa Musoke
Radboud University
I. Myserlis
Institut de Radioastronomie Millimétrique (IRAM)
Andrew Nadolski
University of Illinois
H. Nagai
National Astronomical Observatory of Japan
N. M. Nagar
University of Concepcion
Masanori Nakamura
Academia Sinica
Gopal Narayanan
University of Massachusetts
Iniyan Natarajan
Harvard University
Antonios Nathanail
Goethe University Frankfurt
S. Navarro Fuentes
Institut de Radioastronomie Millimétrique (IRAM)
Joseph Neilsen
Villanova University
R. Neri
Institut de Radioastronomie Millimétrique (IRAM)
Chunchong Ni
Perimeter Institute for Theoretical Physics
A. Noutsos
Max Planck Society
Michael A. Nowak
Washington University in St. Louis
Junghwan Oh
Joint Institute for VLBI in Europe (JIVE)
Hiroki Okino
National Astronomical Observatory of Japan
Héctor Olivares
Centre For Research And Development In Mathematics And Applications (CIDMA)
G.N. Ortiz-León
Max Planck Society
Tomoaki Oyama
National Astronomical Observatory of Japan
Feryal Özel
Georgia Institute of Technology
Daniel C.M. Palumbo
Harvard University
Jongho Park
Academia Sinica
Harriet Parsons
East Asian Observatory
N. Patel
Harvard-Smithsonian Center for Astrophysics
U. L. Pen
Academia Sinica
Dominic W. Pesce
Harvard University
Vincent Piétu
Institut de Radioastronomie Millimétrique (IRAM)
Richard L. Plambeck
University of California
Aleksandar PopStefanija
University of Massachusetts
Oliver Porth
Goethe University Frankfurt
Felix M. Pötzl
Foundation for Research and Technology Hellas (FORTH)
Ben Prather
The Grainger College of Engineering
Jorge A. Preciado-López
Perimeter Institute for Theoretical Physics
G. Principe
Istituto di Radioastronomia
Dimitrios Psaltis
Georgia Institute of Technology
Hung-Yi Pu
Academia Sinica
Venkatessh Ramakrishnan
University of Concepcion
R. Rao
Harvard-Smithsonian Center for Astrophysics
M.G. Rawlings
East Asian Observatory
Angelo Ricarte
Harvard University
Bart Ripperda
Perimeter Institute for Theoretical Physics
Freek Roelofs
Radboud University
A.E.E. Rogers
Massachusetts Institute of Technology (MIT)
C. Romero-Cañizales
Academia Sinica
Arash Roshanineshat
University of Arizona
H. Rottmann
Max Planck Society
A. Roy
Max Planck Society
Ignacio Ruiz
Institut de Radioastronomie Millimétrique (IRAM)
C. Ruszczyk
Massachusetts Institute of Technology (MIT)
Kazi L.J. Rygl
Istituto di Radioastronomia
S. Sanchez
Institut de Radioastronomie Millimétrique (IRAM)
David Sánchez-Arguelles
National Institute of Astrophysics, Optics and Electronics
M. Sánchez Portal
Institut de Radioastronomie Millimétrique (IRAM)
Mahito Sasada
National Astronomical Observatory of Japan
Kaushik Satapathy
University of Arizona
T. Savolainen
University of Massachusetts
Jonathan Schonfeld
Harvard-Smithsonian Center for Astrophysics
K. Schuster
Institut de Radioastronomie Millimétrique (IRAM)
Lijing Shao
Max Planck Society
Zhi Qiang Shen
Chinese Academy of Sciences
Des Small
Joint Institute for VLBI in Europe (JIVE)
B. W. Sohn
Korea Astronomy and Space Science Institute
J. SooHoo
Massachusetts Institute of Technology (MIT)
León David Sosapanta Salas
Anton Pannekoek Institute for Astronomy
Kamal Souccar
University of Massachusetts
Joshua S. Stanway
University of Central Lancashire
He Sun
Beijing University of Technology
Fumie Tazaki
National Astronomical Observatory of Japan
Alexandra J. Tetarenko
University of Lethbridge
Paul Tiede
Harvard University
M. Titus
Massachusetts Institute of Technology (MIT)
Pablo Torne
Max Planck Society
Teresa Toscano
Spanish National Research Council (CSIC)
Tyler Trent
University of Arizona
S. Trippe
Seoul National University
Matthew Turk
University of Illinois
I. van Bemmel
Netherlands Institute for Radio Astronomy (ASTRON)
H. J. van Langevelde
Leiden University
Daniel R. van Rossum
Radboud University
Jesse Vos
Radboud University
Jan Wagner
Max Planck Society
D. Ward-Thompson
University of Central Lancashire
John Wardle
Brandeis University
Jasmin E. Washington
University of Arizona
J. Weintroub
Harvard University
Robert Wharton
Max Planck Society
K. Wiik
Aalto University
Gunther Witzel
Max Planck Society
Michael F. Wondrak
Radboud University
George N. Wong
Princeton University
Qingwen Wu
Huazhong University of Science and Technology
Nitika Yadlapalli
California Institute of Technology (Caltech)
Paul Yamaguchi
Harvard-Smithsonian Center for Astrophysics
Aristomenis Yfantis
Radboud University
Doosoo Yoon
Anton Pannekoek Institute for Astronomy
A. Young
Radboud University
Ken Young
Harvard-Smithsonian Center for Astrophysics
Ziri Younsi
Goethe University Frankfurt
Wei Yu
Harvard-Smithsonian Center for Astrophysics
Feng Yuan
Fudan University
Ye-Fei Yuan
University of Science and Technology of China
A.J. Zensus
Max Planck Society
Shuo Zhang
Michigan State University
G. Y. Zhao
Max Planck Society
Shan-Shan Zhao
Chinese Academy of Sciences
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 695 A233Subject Categories (SSIF 2025)
Astronomy, Astrophysics, and Cosmology
Meteorology and Atmospheric Sciences
DOI
10.1051/0004-6361/202452600