Locating the missing large-scale emission in the jet of M87*with short EHT baselines
Journal article, 2026
In very-long baseline interferometric arrays, nearly co-located stations probe the largest scales and typically cannot resolve the observed source. In the absence of a large-scale structure, closure phases constructed with these stations are zero and, since they are independent of station-based errors, they can be used to probe data issues. Here, we show how these trivial closure phases become nonzero with a brightness distribution on smaller scales than their short baseline would suggest. When applied to sources that are made up of a bright compact and large-scale diffuse component, the trivial closure phases directly measure the centroid relative to the compact source and higher-order image moments. We present a technique to measure these image moments with minimal model assumptions and validate it on synthetic Event Horizon Telescope (EHT) data. We then apply this technique to 2017 and 2018 EHT observations of M87* and find a weak preference for extended emission in the direction of the large-scale jet. We also apply it to 2021 EHT data and measure the source centroid about 1 mas northwest of the compact ring, which is consistent with the jet observed at lower frequencies.
galaxies: individual: M87*
techniques: interferometric
galaxies: jets
black hole physics
galaxies: active
Author
Boris Georgiev
University of Arizona
Paul Tiede
Harvard-Smithsonian Center for Astrophysics
Harvard University
Sebastiano D. von Fellenberg
Max Planck Society
University of Toronto
Michael Janssen
Radboud University
Max Planck Society
Iniyan Natarajan
Harvard-Smithsonian Center for Astrophysics
Harvard University
Lindy Blackburn
Harvard University
Harvard-Smithsonian Center for Astrophysics
Jongho Park
Academia Sinica
Kyung Hee University
Erandi Chavez
Harvard-Smithsonian Center for Astrophysics
Andrew T. West
University of Arizona
Kotaro Moriyama
National Astronomical Observatory of Japan
Spanish National Research Council (CSIC)
Jun Yi Koay
Academia Sinica
Niigata University
Hendrik Mueller
Max Planck Society
Dhanya G. Nair
University of Concepcion
Max Planck Society
Avery E. Broderick
University of Waterloo
Perimeter Institute for Theoretical Physics
Maciek Wielgus
Spanish National Research Council (CSIC)
Kazunori Akiyama
National Astronomical Observatory of Japan
Massachusetts Institute of Technology (MIT)
Harvard University
Ezequiel Albentosa-Ruiz
Universitat de Valencia
Antxon Alberdi
Spanish National Research Council (CSIC)
Walter Alef
Max Planck Society
Juan Carlos Algaba
University of Malaya
Richard Anantua
Harvard-Smithsonian Center for Astrophysics
University of Texas
Rice University
Harvard University
Keiichi Asada
Academia Sinica
Rebecca Azulay
Universitat de Valencia
Max Planck Society
Uwe Bach
Max Planck Society
Anne-Kathrin Baczko
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
David Ball
University of Arizona
Mislav Balokovic
Yale University
Bidisha Bandyopadhyay
University of Concepcion
John Barrett
Massachusetts Institute of Technology (MIT)
Michi Baubock
University of Illinois
Bradford A. Benson
University of Chicago
Fermi National Accelerator Laboratory
Dan Bintley
East Asian Observatory
James Clerk Maxwell Telescope
Raymond Blundell
Harvard-Smithsonian Center for Astrophysics
Katherine L. Bouman
California Institute of Technology (Caltech)
Geoffrey C. Bower
Academia Sinica
University of Hawaii
James Clerk Maxwell Telescope
East Asian Observatory
Michael Bremer
Institut de Radioastronomie Millimétrique (IRAM)
Roger Brissenden
Harvard-Smithsonian Center for Astrophysics
Silke Britzen
Max Planck Society
Dominique Broguiere
Institut de Radioastronomie Millimétrique (IRAM)
Thomas Bronzwaer
Radboud University
Sandra Bustamante
University of Massachusetts
Douglas F. Carlos
University of Sao Paulo (USP)
John E. Carlstrom
University of Chicago
Andrew Chael
Princeton University
Chi-kwan Chan
University of Arizona
Dominic O. Chang
Harvard University
Harvard-Smithsonian Center for Astrophysics
Koushik Chatterjee
Harvard University
Harvard-Smithsonian Center for Astrophysics
University of Maryland
Shami Chatterjee
Cornell University
Ming-Tang Chen
Academia Sinica
Yongjun Chen
Chinese Academy of Sciences
Xiaopeng Cheng
Korea Astronomy and Space Science Institute
Paul Chichura
University of Chicago
Ilje Cho
Nanjing University
Spanish National Research Council (CSIC)
Yonsei University
Pierre Christian
WattTime
Nicholas S. Conroy
University of Illinois
Harvard-Smithsonian Center for Astrophysics
John E. Conway
Chalmers, Space, Earth and Environment, Onsala Space Observatory
Thomas M. Crawford
University of Chicago
Geoffrey B. Crew
Massachusetts Institute of Technology (MIT)
Alejandro Cruz-Osorio
Goethe University Frankfurt
Universidad Nacional Autónoma de México
Yuzhu Cui
Central China Normal University
Brandon Curd
University of Texas
Harvard-Smithsonian Center for Astrophysics
Harvard University
Rohan Dahale
Spanish National Research Council (CSIC)
Jordy Davelaar
Princeton University
Mariafelicia De laurentis
National Institute for Nuclear Physics
University of Naples Federico II
Roger Deane
University of Pretoria
University of Witwatersrand
Rhodes University
Gregory Desvignes
Paris Descartes University
Max Planck Society
Jason Dexter
University of Colorado
Vedant Dhruv
University of Illinois
Indu K. Dihingia
Shanghai Jiao Tong University
Sheperd S. Doeleman
Harvard University
Harvard-Smithsonian Center for Astrophysics
Sergio A. Dzib
Max Planck Society
Ralph P. Eatough
Max Planck Society
Chinese Academy of Sciences
Razieh Emami
Harvard-Smithsonian Center for Astrophysics
Heino Falcke
Radboud University
Joseph Farah
Las Cumbres Observatory Global Telescope Network
University of California
Vincent L. Fish
Massachusetts Institute of Technology (MIT)
Edward Fomalont
National Radio Astronomy Observatory
H. Alyson Ford
University of Arizona
Marianna Foschi
Spanish National Research Council (CSIC)
Raquel Fraga-Encinas
Radboud University
William T. Freeman
Google Inc.
Massachusetts Institute of Technology (MIT)
Per Friberg
East Asian Observatory
James Clerk Maxwell Telescope
Christian M. Fromm
University of Würzburg
Goethe University Frankfurt
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)
Ciriaco Goddi
Istituto nazionale di astrofisica (INAF)
University of Sao Paulo (USP)
University of Cagliari
National Institute for Nuclear Physics
Roman Gold
Heidelberg University
University of Southern Denmark
Arturo I. Gomez-Ruiz
National Institute of Astrophysics, Optics and Electronics
National Council for Science and Technology Mexico
Jose L. Gomez
Spanish National Research Council (CSIC)
Minfeng Gu
Chinese Academy of Sciences
Mark Gurwell
Harvard-Smithsonian Center for Astrophysics
Kazuhiro Hada
National Astronomical Observatory of Japan
Nagoya City University
Daryl Haggard
McGill University
Ronald Hesper
University of Groningen
Dirk Heumann
University of Arizona
Luis C. Ho
Beijing University of Technology
Paul Ho
James Clerk Maxwell Telescope
Academia Sinica
East Asian Observatory
Mareki Honma
The Graduate University for Advanced Studies (SOKENDAI)
University of Tokyo
National Astronomical Observatory of Japan
Chih-Wei L. Huang
Academia Sinica
Lei Huang
Chinese Academy of Sciences
David H. Hughes
National Institute of Astrophysics, Optics and Electronics
Shiro Ikeda
University of Tokyo
National Astronomical Observatory of Japan
The Graduate University for Advanced Studies (SOKENDAI)
The Institute of Statistical Mathematics
C. M. Violette Impellizzeri
National Radio Astronomy Observatory
Leiden University
Makoto Inoue
Academia Sinica
Sara Issaoun
Harvard-Smithsonian Center for Astrophysics
David J. James
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Buell T. Jannuzi
University of Arizona
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University of Turku
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Chinese Academy of Sciences
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Radboud University
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Harvard University
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Boston University
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University of Chicago
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University of Illinois
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University of Science and Technology (UST)
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Ulsan National Institute of Science and Technology (UNIST)
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Korea Advanced Institute of Science and Technology (KAIST)
Motoki Kino
Kogakuin University of Technology and Engineering
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Harvard University
Harvard-Smithsonian Center for Astrophysics
Yutaro Kofuji
University of Tokyo
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Academia Sinica
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Institut de Radioastronomie Millimétrique (IRAM)
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University of Amsterdam
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Max Planck Society
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Max Planck Society
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National Sun Yat-Sen University
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Radboud University
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Kyungpook National University
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Korea Astronomy and Space Science Institute
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California Institute of Technology (Caltech)
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Nanjing University
Rocco Lico
Spanish National Research Council (CSIC)
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Chalmers, Space, Earth and Environment, Onsala Space Observatory
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Pontificia Universidad Católica de Valparaíso
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Max Planck Society
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Chinese Academy of Sciences
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Chinese Academy of Sciences
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Chinese Academy of Sciences
Nicola Marchili
Italian ALMA Regional Centre
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Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 709 A26Subject Categories (SSIF 2025)
Fusion, Plasma and Space Physics
Astronomy, Astrophysics, and Cosmology
DOI
10.1051/0004-6361/202557013