Finnish Center for Astronomy with ESO, FI-20014, University of Turku, Turku, Finland
Ioannis Liodakis, Jenni Jormanainen, Elina Lindfors & Kari Nilsson
Astrophysical Research Institute, Boston University, Boston, MA, USA
Alan P. Marscher, Svetlana G. Jorstad, and Zachary R. Weaver
Institute of Astrophysics of Andalusia, IAA-CSIC, Glorieta de la Astronomía s/n, Granada, Spain
Iván Agudo, Maria I. Bernardos, Giacomo Bonnoli, Vı́ctor Casanova, Juan Escudero, Maya Garcı́a-Comas, Beatriz Agı́s-González, César Husillos & Alfredo Sota
Department of Physics and Astronomy, University of Turku, Turku, Finland
Andrei V. Berdyugin, Jenni Jormanainen, Vadim Kravtsov, Juri Poutanen and Sergey Tsygankov
INAF Astronomical Observatory of Brera, Merate (LC), Italy
Giacomo Bonnoli and Fabrice Tavecchio
Crimean Astrophysical Observatory RAS, P/O Nauchny, Nauchnij, Crimea
George A. Borman and Alexey V. Zhovtan
Institute of Astrophysics, Foundation for Research and Technology – Hellas, Voutes, Heraklion, Greece
Caroline Casadio
Department of Physics, University of Crete, Heraklion, Greece
Caroline Casadio
Italian Space Agency, Via del Politecnico snc, Rome, Italy
Elisabetta Cavazzuti, Laura Di Gesu, Immacolata Donnarumma, Simonetta Puccetti & Andrea Marinucci
Department of Physics and McDonnell Center for the Space Sciences, Washington University in St Louis, St Louis, MO, USA
Nicole Rodriguez Cavero, Manel Errando and Henric Krawczynski
Department of Physics and Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, California, USA
Niccoló Di Lalla, Nicola Omodei, Abel L. Peirson & Roger W. Romani
NASA Marshall Space Flight Center, Huntsville, AL, USA
Steven R. Ehlert, Stephen L. O’Dell, Wayne H. Baumgartner, Stephen D. Bongiorno, Jeffery J. Kolodziejczak, Brian D. Ramsey, Allyn F. Tennant, Nicolas E. Thomas, and Martin C. Weisskopf
Observational Astrophysics Laboratory, Saint Petersburg University, Saint Petersburg, Russia
Svetlana G. Jorstad
Graduate School of Science, Tohoku University, Sendai, Japan
Masato Kagitani and Takeshi Sakanoi
Institute of Astronomy, Saint Petersburg State University, Saint Petersburg, Russia
Evgenia N. Kopatskaya, Elena G. Larionova, Daria A. Morozova, Sergey S. Savchenko and Andrey A. Vasilyev
Kavli Institute for Particle Astrophysics and Cosmology, Stanford University and SLAC, Menlo Park, California, USA
Grzegorz M. Madejski
University of Strasbourg, CNRS, Strasbourg Astronomical Observatory, UMR 7550, Strasbourg, France
Frederic Marin
Department of Physical Sciences, Earth and Environment, Astronomical Observatory, University of Siena, Siena, Italy
Alessandro Marchini
MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA, USA
Herman L. Marshall
National Institute of Nuclear Physics, Turin Section, Turin, Italy
Francesco Massaro, Alessandro Paggi, Raffaella Bonino, Luca Latronico, Simone Maldera & Chiara Oppedisano
Department of Physics, University of Turin, Turin, Italy
Francesco Massaro, Alessandro Paggi and Raffaella Bonino
Caltech/IPAC, Pasadena, CA, USA
Joseph R. Masiero
California Institute of Technology, Pasadena, California, USA
Dimitri Mawet, Georgia V. Panopoulou & Javier A. Garcia
Space Science Data Center, Italian Space Agency, Rome, Italy
Riccardo Middei, Matteo Perri, Lucio A. Antonelli & Stefano Ciprini
INAF Astronomical Observatory of Rome, Monte Porzio Catone (RM), Italy
Riccardo Middei, Matteo Perri, Lucio A. Antonelli & Alessandro Papitto
University of California, Santa Barbara, California, USA
Maxwell A. Millar-Blanchaer
Institute of Millimetric Radio Astronomy, Granada, Spain
John Myserlis
Center for Research and Exploration in Space Science and Technology (CRESST), Greenbelt, MD, USA
Michele Negre
Department of Physics and Center for Space Science and Technology, University of Maryland Baltimore County, Baltimore, MD, USA
Michele Negre
INAF Institute of Space Astrophysics and Planetology, Rome, Italy
Luigi Pacciani, Fiamma Capitanio, Enrico Costa, Alessandra De Rosa, Ettore Del Monte, Alessandro Di Marco, Yuri Evangelista, Sergio Fabiani, Riccardo Ferrazzoli, Fabio La Monaca, Fabio Muleri, John Rankin, Ajay Ratheesh, Paolo Soffitta & Fei Xie
INAF-Turin Astrophysical Observatory, Pino Torinese, Italy
Alessandro Paggi
Grenoble Alpes University, CNRS, IPAG, Grenoble, France
Pierre-Olivier Petrucci
Space Research Institute of the Russian Academy of Sciences, Moscow, Russia
Juri Poutanen, Victor Doroshenko and Sergei Tsygankov
Special Astrophysical Observatory, Russian Academy of Sciences, Nizhnii Arkhyz, Russia
Sergei S. Savchenko
Pulkovo Observatory, Saint Petersburg, Russia
Sergei S. Savchenko
University of California, Santa Cruz, Santa Cruz, California, USA
Samaporn Tinyanont
INAF Astronomical Observatory of Cagliari, Selargius (CA), Italy
Matteo Bachetti, Maura Pilia, Andrea Possenti & Alessio Trois
National Institute of Nuclear Physics, Pisa Section, Pisa, Italy
Luca Baldini, Ronaldo Bellazzini, Alessandro Brez, Simone Castellano, Alberto Manfreda, Melissa Pesce-Rollins, Carmelo Sgró & Gloria Spandre
Department of Physics, University of Pisa, Pisa, Italy
Luca Baldini
Department of Mathematics and Physics, Roma Tre University, Rome, Italy
Stefano Bianchi and Giorgio Matt
INAF Arcetri Astrophysical Observatory, Florence, Italy
Nicolas Bucciantini
Department of Physics and Astronomy, University of Florence, Sesto Fiorentino (FI), Italy
Nicolas Bucciantini
National Institute of Nuclear Physics, Section of Florence, Sesto Fiorentino (FI), Italy
Nicolas Bucciantini
National Institute of Nuclear Physics, Section of Rome Tor Vergata, Rome, Italy
Stefano Ciprini
Institute of Astronomy and Astrophysics, Tübingen, Germany
Viktor Doroshenko
Astronomical Institute of the Czech Academy of Sciences, Ondřejov, Czech Republic
Michal Dovciak & Vladimir Karas
RIKEN Cluster for Pioneering Research, Saitama, Japan
Teruaki Enoto, Takao Kitaguchi & Toru Tamagawa
Yamagata University, Yamagata-shi, Japan
Shuichi Gunji
Osaka University, Osaka, Japan
Kiyoshi Hayashida
University of British Columbia, Vancouver, British Columbia, Canada
Jeremy Heil
Department of Physics, Faculty of Science and Engineering, Chuo University, Tokyo, Japan
Wataru Iwakiri
Graduate School of Science, Division of Particle and Astrophysical Science, University of Nagoya, Nagoya, Japan
Ikuyuki Mitsuishi and Yuzuru Tawara
Hiroshima Astrophysical Science Center, Hiroshima University, Hiroshima, Japan
Tsunefumi Mizuno
Department of Physics, University of Hong Kong, Pokfulam, Hong Kong
Stephen C.-Y. ENGLISH
Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA, USA
George G. Pavlov
Center for Astrophysics, Harvard & Smithsonian, Cambridge, MA, USA
Patrick Slane
Department of Physics and Astronomy, University of Padua, Padua, Italy
Roberto Taverna and Roberto Turolla
Department of Physics, University of Rome Tor Vergata, Rome, Italy
Francesco Tombesi
Mullard Space Science Laboratory, University College London, Dorking, UK
Roberto Turolla, Kinwah Wu and Silvia Zane
Anton Pannekoek Institute for Astronomy & GRAPPA, University of Amsterdam, Amsterdam, The Netherlands
Jack Vink
Guangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University, Nanning, China
Fei Xie
He coordinated the multi-wavelength observations, performed the analysis, and led the writing of the paper. HK, APM, LP, P.-OP, JP, F. Tavecchio and RWR contributed to the discussion and parts of the document. IA, CC, JE and I. Myserlis provided the millimeter radio polarization data. BA-G., IA, AVB, MB, GB, VC, MG-C., CH, JJ, V. Kravtsov, EL, IL, KN, SSS and AS provided optical polarization data. GVP provided the infrared polarization data. APM, GMM, RM, LP, M. Perri and SP provided Swift and NuSTAR data. LDG, NDL, ID, SRE, HLM, RM, MN, NO, A. Paggi and ALP contributed to the IXPE analysis. The other authors are part of the multi-wavelength and IXPE monitoring teams whose significant contribution made the multi-wavelength polarization observations possible.