First polarization study of the M87 jet and active galactic nuclei at submillimeter wavelengths with ALMA

Aims. We investigated the polarization and Faraday properties of Messier 87 (M87) and seven other radio-loud active galactic nuclei (AGNs) at λ 0.87 mm (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 10 5 rad m −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.

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Publication Details

Journal
Astronomy and Astrophysics
Published
2025-05-17
DOI
https://doi.org/10.1051/0004-6361/202554140
Citations
5
Primary Topic
Astrophysics and Cosmic Phenomena
Type
article
Field-Weighted Citation Impact
9.35

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article

First polarization study of the M87 jet and active galactic nuclei at submillimeter wavelengths with ALMA

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5 citations
Astronomy and Astrophysics
Astrophysics and Cosmic Phenomena
9.35
article

First polarization study of the M87 jet and active galactic nuclei at submillimeter wavelengths with ALMA

Chi‐kwan Chan, Richard Anantua, Paul Yamaguchi, Doosoo Yoon, S. Britzen, Ezequiel Albentosa-Ruíz, Monika Mościbrodzka, Kenji Toma, Sandra Bustamante, A. Alberdi, Matthew Turk, Dominique Broguière, R. Blundell, Jason Soohoo, Svetlana G. Jorstad, Ming‐Tang Chen, Hiroki Okino, Alejandro Mus, Kaushik Satapathy, Anne-Kathrin Baczko, Bidisha Bandyopadhyay, Guang-Yao Zhao, Wen-Ping Lo, John Barrett, Juan Carlos Algaba, Ilse van Bemmel, I. Myserlis, Amy Benson, Kazunori Akiyama, J. A. Zensus, Motoki Kino, Aviad Levis, Michael A. Nowak, Shiro Ikeda, Andrew Chael, C. Goddi, Roger Brissenden, Marianna Foschi, Michi Bauböck, S. Silpa, K. Schüster, Jonathan Schonfeld, J. Montgomery, T. P. Krichbaum, Ziri Younsi, N. Marchili, H. Falcke, U. Bach, Hugo Messias, M. Lindqvist, Michael F. Wondrak, T. M. Crawford, Jessica Dempsey, Pablo Torné, Shami Chatterjee, Mariafelicia De Laurentis, Freek Roelofs, P. Andrei Lobanov, Alexandra J. Tetarenko, T. Freeman, Joseph Farah, Rebecca Azulay, Raquel Fraga-Encinas, A. L. Roy, C. Ho, Douglas Ferreira Carlos, Nimesh Patel, Michael Bremer, Thomas Bronzwaer, Venkatessh Ramakrishnan, Mahito Sasada, Eric Carlström, Ralph P. Eatough, David Sánchez-Argüelles, Mark Gurwell, André Young, Harriet Parsons, Sara Issaoun, E. Ros, William T. Freeman, Koushik Chatterjee, Masanori Nakamura, Keiichi Asada, Rohan Dahale, K. M. Menten, Mislav Baloković, Elisabetta Liuzzo, O. Chang, Oliver Porth, Lindy Blackburn, Brandon Curd, Tyler Trent, Yosuke Mizuno, Aristomenis Yfantis, Daniel C. M. Palumbo, Cornelia Müller, Joshua S. Stanway, Jae-Young Kim, Shuo Zhang, Jongho Park, Wei Yu, Roberto García, H. Alyson Ford, F. Peter Schloerb, Qingwen Wu, Ye‐Fei Yuan, V. Piétu, D. H. Hughes, Lynn D. Matthews, W. Alef, Yutaro Kofuji, Junhan Kim, Iván Martí-Vidal, Dan Bintley, Rocco Lico, David Ball, C. Bower, Michael E. Moran, Nitika Yadlapalli, S. Nicholas Conroy, T. Buell Jannuzi, L.J. Kazi Rygl, 毛基荣, W. Dominic Pesce, R. Daniel van Rossum, 吴庆文, G. Crew, L. Katherine Bouman, E. Avery Broderick, K. Indu Dihingia, 何子山, Zhiyuan Li, Xiaopeng Cheng, Abhishek V. Joshi, Ru-Sen Lu, Xiaopeng Cheng
article en
5 citations

Abstract

Aims. We investigated the polarization and Faraday properties of Messier 87 (M87) and seven other radio-loud active galactic nuclei (AGNs) at λ 0.87 mm (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 10 5 rad m −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.

Astronomy and AstrophysicsVol. 699
National Science Foundation, Smithsonian Institution, U.S. Department of Energy, National Aeronautics and Space Administration, John Templeton Foundation, Gordon and Betty Moore Foundation, University of Chicago, University of Arizona, CERN, Netherlands eScience Center, Ministerio de Ciencia, Innovación y Universidades, National Radio Astronomy Observatory, International Max Planck Research School for Environmental, Cellular and Molecular Microbiology, Joint Institute for Computational Fundamental Science, Flatiron Health, Government of Canada, Leverhulme Trust, European Commission, National Research Foundation, University of Pretoria, Deutsche Forschungsgemeinschaft, Ministry of Education, Culture, Sports, Science and Technology, Universiteit Leiden, Canada Research Chairs, Fundação de Amparo à Pesquisa do Estado de São Paulo, National Natural Science Foundation of China, Universiteit van Amsterdam, Radboud Universiteit, Academia Sinica, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Chinese Academy of Sciences, China Postdoctoral Science Foundation, Nederlandse Organisatie voor Wetenschappelijk Onderzoek, Generalitat Valenciana, Korea Astronomy and Space Science Institute, National Research Foundation of Korea, Max-Planck-Gesellschaft, Vetenskapsrådet, China Scholarship Council, Centre National de la Recherche Scientifique, Ministerio de Ciencia e Innovación, Shanghai Jiao Tong University, Universidad Nacional Autónoma de México, National Astronomical Observatory of Japan, Junta de Andalucía, Istituto Nazionale di Fisica Nucleare, Ministry of Science and ICT, South Korea, Fundación Bancaria Caixa d'Estalvis i Pensions de Barcelona, Instituto de Astrofísica de Andalucía, Agencia Nacional de Investigación y Desarrollo, National Science and Technology Council, Alliance de recherche numérique du Canada, Institut Périmètre de physique théorique, East Asian Core Observatories Association, Toray Science Foundation, Office of Science, National Nuclear Security Administration, HORIZON EUROPE Framework Programme, Science and Technology Facilities Council, Japan Society for the Promotion of Science, Fundação para a Ciência e a Tecnologia, Fonds de recherche du Québec – Nature et technologies, Consejo Superior de Investigaciones Científicas, Dirección General de Asuntos del Personal Académico, Universidad Nacional Autónoma de México, National Institutes of Natural Sciences, Agencia Estatal de Investigación, National Key Research and Development Program of China, High Energy Physics, Oak Ridge National Laboratory, Los Alamos National Laboratory
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Astrophysics and Cosmic Phenomena
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