First polarization study of the M87 jet and active galactic nuclei at submillimeter wavelengths with ALMA
Journal article, 2025
Aims. We investigated the polarization and Faraday properties of Messier 87 (M87) and seven other radio-loud active galactic nuclei (AGNs) at _0.87mm (345 GHz) using the Atacama Large Millimeter/submillimeter Array (ALMA). Our goal was to characterize the linear polarization (LP) fractions, measure Faraday rotation measures (RMs), and examine the magnetic field structures in the emission regions of these AGNs. Methods. We conducted full-polarization observations as part of the ALMA Band 7 very long baseline interferometry (VLBI) commissioning during the April 2021 Event Horizon Telescope (EHT) campaign. We analyzed the LP fractions and RMs to assess the nature of Faraday screens and magnetic fields in the submillimeter emission regions. Results. We find LP fractions between 1% and 17% and RMs exceeding 105 radm-2, which are 1-2 orders of magnitude higher than typically observed at longer wavelengths (λ > 3 mm). This suggests denser Faraday screens or stronger magnetic fields. Additionally, we present the first submillimeter polarized images of the M87 jet and the observed AGNs, revealing RM gradients and sign reversals in the M87 jet indicative of a kiloparsec-scale helical magnetic field structure. Conclusions. Our results provide essential constraints for calibrating, analyzing, and interpreting VLBI data from the EHT at 345 GHz, representing a critical step toward submillimeter VLBI imaging.
Instrumentation: interferometers
Polarization
Instrumentation: polarimeters
Black hole physics
Radiation mechanisms: non-thermal
Magnetic fields
Author
C. Goddi
University of Sao Paulo (USP)
Istituto nazionale di astrofisica (INAF)
University of Cagliari
Douglas Ferreira Carlos
University of Sao Paulo (USP)
G. Crew
Massachusetts Institute of Technology (MIT)
Lynn D. Matthews
Massachusetts Institute of Technology (MIT)
H. Messias
Atacama Large Millimeter-submillimeter Array (ALMA)
A. Mus
Istituto di Radioastronomia
University of Cagliari
Ivan Marti-Vidal
Universitat de Valencia
E. Albentosa-Ruiz
Universitat de Valencia
Mariafelicia De Laurentis
University of Naples Federico II
National Institute for Nuclear Physics
Elisabetta Liuzzo
Istituto di Radioastronomia
Nicola Marchili
Istituto di Radioastronomia
Max Planck Society
Kazi L.J. Rygl
Istituto di Radioastronomia
Kazunori Akiyama
Massachusetts Institute of Technology (MIT)
National Astronomical Observatory of Japan
Harvard University
Antxon Alberdi
Spanish National Research Council (CSIC)
Walter Alef
Max Planck Society
Juan Carlos Algaba
University of Malaya
Richard Anantua
University of Texas
Rice University
Harvard University
Harvard-Smithsonian Center for Astrophysics
K. Asada
Academia Sinica
R. Azulay
Max Planck Society
Universitat de Valencia
U. Bach
Max Planck Society
Anne-Kathrin Baczko
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Max Planck Society
David Ball
University of Arizona
Mislav Balokoviä
Yale University
Bidisha Bandyopadhyay
University of Concepcion
John Barrett
Massachusetts Institute of Technology (MIT)
M. Bauböck
Grainger College of Engineering
Bradford A. Benson
Fermi National Accelerator Laboratory
University of Chicago
Dan Bintley
James Clerk Maxwell Telescope
East Asian Observatory
Lindy Blackburn
Harvard University
Harvard-Smithsonian Center for Astrophysics
R. Blundell
Harvard-Smithsonian Center for Astrophysics
K. L. Bouman
California Institute of Technology (Caltech)
G. C. Bower
University of Hawaii
Academia Sinica
M. Bremer
Institut de Radioastronomie Millimétrique (IRAM)
Roger Brissenden
Harvard-Smithsonian Center for Astrophysics
Harvard University
Silke Britzen
Max Planck Society
Avery E. Broderick
University of Waterloo
Perimeter Institute for Theoretical Physics
D. Broguière
Institut de Radioastronomie Millimétrique (IRAM)
Thomas Bronzwaer
Radboud University
Sandra Bustamente
University of Massachusetts
J. E. Carlstrom
University of Chicago
The Enrico Fermi Institute
A. Chael
Princeton University
Chi Kwan Chan
University of Arizona
Dominic O. Chang
Harvard-Smithsonian Center for Astrophysics
Harvard University
Koushik Chatterjee
Harvard-Smithsonian Center for Astrophysics
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
Yonsei University
Korea Astronomy and Space Science Institute
Spanish National Research Council (CSIC)
Pierre Christian
WattTime
Nicholas S. Conroy
University of Illinois
Harvard-Smithsonian Center for Astrophysics
John Conway
Chalmers, Space, Earth and Environment, Onsala Space Observatory
Thomas M. Crawford
University of Chicago
Alejandro Cruz-Osorio
Universidad Nacional Autónoma de México
Goethe University Frankfurt
Yuzhu Cui
Shanghai Jiao Tong University
Zhejiang Lab
Brandon Curd
Harvard University
Harvard-Smithsonian Center for Astrophysics
University of Texas
Rohan Dahale
Spanish National Research Council (CSIC)
Jordy Davelaar
Princeton University
R. P. Deane
University of Pretoria
University of Witwatersrand
Rhodes University
Jessica Dempsey
James Clerk Maxwell Telescope
Netherlands Institute for Radio Astronomy (ASTRON)
East Asian Observatory
Gregory Desvignes
Paris Observatory
Max Planck Society
Jason Dexter
JILA
Vedant Dhruv
Grainger College of Engineering
Indu K. Dihingia
Shanghai Jiao Tong University
S. Doeleman
Harvard-Smithsonian Center for Astrophysics
Harvard University
Sergio A. Dzib
Max Planck Society
Ralph P. Eatough
Chinese Academy of Sciences
Max Planck Society
Razieh Emami
Harvard-Smithsonian Center for Astrophysics
H.D. Falcke
Radboud University
Joseph R. Farah
Las Cumbres Observatory Global Telescope Network
University of California
V. Fish
Massachusetts Institute of Technology (MIT)
E. Fomalont
National Radio Astronomy Observatory
Marianna Foschi
Spanish National Research Council (CSIC)
R. Fraga-Encinas
Radboud University
William T. Freeman
Google Inc.
Massachusetts Institute of Technology (MIT)
P. Friberg
James Clerk Maxwell Telescope
East Asian Observatory
Christian M. Fromm
University of Würzburg
Max Planck Society
Goethe University Frankfurt
Antonio Fuentes
Spanish National Research Council (CSIC)
Peter Galison
Harvard University
Charles F. Gammie
University of Illinois
Grainger College of Engineering
Roberto Garcia
Institut de Radioastronomie Millimétrique (IRAM)
Olivier Gentaz
Institut de Radioastronomie Millimétrique (IRAM)
Boris Georgiev
University of Arizona
R. Gold
Institut für Theoretische Physik Heidelberg
University of Southern Denmark
Heidelberg University
Arturo I. Gómez-Ruiz
National Council for Science and Technology Mexico
National Institute of Astrophysics, Optics and Electronics
J. L. Gomez
Spanish National Research Council (CSIC)
Minfeng Gu
Chinese Academy of Sciences
M. Gurwell
Harvard-Smithsonian Center for Astrophysics
K. Hada
University of Tokyo
National Astronomical Observatory of Japan
Daryl Haggard
McGill University
R. Hesper
University of Groningen
Dirk Heumann
University of Arizona
Luis C. Ho
Beijing University of Technology
P. T. P. Ho
Academia Sinica
James Clerk Maxwell Telescope
East Asian Observatory
Mareki Honma
The Graduate University for Advanced Studies (SOKENDAI)
National Astronomical Observatory of Japan
University of Tokyo
Chih Wei L. Huang
Academia Sinica
Lei Huang
Chinese Academy of Sciences
D. Hughes
National Institute of Astrophysics, Optics and Electronics
Shiro Ikeda
The Graduate University for Advanced Studies (SOKENDAI)
The Institute of Statistical Mathematics
National Astronomical Observatory of Japan
University of Tokyo
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 699 A265Subject Categories (SSIF 2025)
Atom and Molecular Physics and Optics
Astronomy, Astrophysics, and Cosmology
Meteorology and Atmospheric Sciences
DOI
10.1051/0004-6361/202554140