Compact radio emission indicates a structured jet was produced by a binary neutron star merger

G. Ghirlanda

Istituto Nazionale di Astrofisica–Osservatorio Astronomico di Brera, Via E. Bianchi 46, I-23807 Merate, Italy.Dipartimento di Fisica G. Occhialini, Università di Milano-Bicocca, Piazza della Scienza 3, IT-20126 Milano, Italy.Sezione di Milano Bicocca, Istituto Nazionale Fisica Nucleare (INFN), Piazza della Scienza 3, 20126 Milano, Italy.

O. S. Salafia

Istituto Nazionale di Astrofisica–Osservatorio Astronomico di Brera, Via E. Bianchi 46, I-23807 Merate, Italy.Dipartimento di Fisica G. Occhialini, Università di Milano-Bicocca, Piazza della Scienza 3, IT-20126 Milano, Italy.Sezione di Milano Bicocca, Istituto Nazionale Fisica Nucleare (INFN), Piazza della Scienza 3, 20126 Milano, Italy.

Z. Paragi

Joint Institute for Very Long Baseline Interferometry (VLBI) European Research Infrastructure Consortium (ERIC), Oude Hoogeveensedijk 4, 7991 PD Dwingeloo, Netherlands.

M. Giroletti

Istituto Nazionale di Astrofisica–Istituto di Radioastronomia, via Gobetti 101, I40129, Bologna, Italia.

J. Yang

Chalmers University of Technology, Onsala Space Observatory, SE-439 92, Sweden.Yunnan Observatories, Chinese Academy of Sciences, 650216 Kunming, Yunnan, China.

B. Marcote

Joint Institute for Very Long Baseline Interferometry (VLBI) European Research Infrastructure Consortium (ERIC), Oude Hoogeveensedijk 4, 7991 PD Dwingeloo, Netherlands.

J. Blanchard

Joint Institute for Very Long Baseline Interferometry (VLBI) European Research Infrastructure Consortium (ERIC), Oude Hoogeveensedijk 4, 7991 PD Dwingeloo, Netherlands.

I. Agudo

Instituto de Astrofísica de Andalucía–Consejo Superior de Investigaciones Científicas (CSIC), Glorieta de la Astronomía s/n, E-18008, Granada, Spain.

T. An

Shanghai Astronomical Observatory, Key Laboratory of Radio Astronomy, Chinese Academy of Sciences, 200030 Shanghai, China.

M. G. Bernardini

Laboratoire Univers et Particules de Montpellier, Universitè de Montpellier, Centre National de la Recherche Scientifique/Institute National de Physique Nucleaire et Physique des Particules (CNRS/IN2P3), place Eugéne Bataillon, F–34085 Montpellier, France.

R. Beswick

Electronic Multi-Element Radio Linked Interferometer Network/Very Long Baseline Interferometry (e-MERLIN/VLBI) National Facility, Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Manchester, UK.

M. Branchesi

Gran Sasso Science Institute, Viale F. Crispi 7, I-67100, L’Aquila, Italy.Laboratori Nazionali del Gran Sasso, INFN, I-67100 L’Aquila, Italy.

S. Campana

Istituto Nazionale di Astrofisica–Osservatorio Astronomico di Brera, Via E. Bianchi 46, I-23807 Merate, Italy.

C. Casadio

Max Planck Institute fur Radioastronomie, Auf dem Huegel 69, Bonn D-53121, Germany.

E. Chassande-Mottin

AstroParticule et Cosmologie (APC), Université Paris Diderot, CNRS/IN2P3, Commissariat à l’Énergie Atomique et aux Énergies Alternatives/ Institute for Research on the Fundamental Laws of the Universe (CEA/IRFU), Observatoire de Paris, Sorbonne Paris Cité, F-75205 Paris Cedex 13, France.

M. Colpi

Dipartimento di Fisica G. Occhialini, Università di Milano-Bicocca, Piazza della Scienza 3, IT-20126 Milano, Italy.Sezione di Milano Bicocca, Istituto Nazionale Fisica Nucleare (INFN), Piazza della Scienza 3, 20126 Milano, Italy.

S. Covino

Istituto Nazionale di Astrofisica–Osservatorio Astronomico di Brera, Via E. Bianchi 46, I-23807 Merate, Italy.

P. D’Avanzo

Istituto Nazionale di Astrofisica–Osservatorio Astronomico di Brera, Via E. Bianchi 46, I-23807 Merate, Italy.

V. D’Elia

Space Science Data Center, Agenzia Spaziale Italiana (ASI), Via del Politecnico, 00133, Roma, Italy.

S. Frey

Konkoly Observatory, Magyar Tudományos Akadémia (MTA) Research Centre for Astronomy and Earth Sciences, Konkoly Thege Miklós út 15-17, H-1121 Budapest, Hungary.

M. Gawronski

Centre for Astronomy, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Torun, Poland.

G. Ghisellini

Istituto Nazionale di Astrofisica–Osservatorio Astronomico di Brera, Via E. Bianchi 46, I-23807 Merate, Italy.

L. I. Gurvits

Joint Institute for Very Long Baseline Interferometry (VLBI) European Research Infrastructure Consortium (ERIC), Oude Hoogeveensedijk 4, 7991 PD Dwingeloo, Netherlands.Department of Astrodynamics and Space Missions, Delft University of Technology, Kluyverweg 1, 2629 HS Delft, Netherlands.

P. G. Jonker

Space Research Organisation of the Netherlands (SRON), Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, Netherlands.Department of Astrophysics, Institute for Mathematics, Astrophysics and Particle Physics (IMAPP), Radboud University, Post Office Box 9010, 6500 GL Nijmegen, Netherlands.

H. J. van Langevelde

Joint Institute for Very Long Baseline Interferometry (VLBI) European Research Infrastructure Consortium (ERIC), Oude Hoogeveensedijk 4, 7991 PD Dwingeloo, Netherlands.Sterrewacht Leiden, Leiden University, Post Office Box 9513, NL-2300 RA Leiden, Netherlands.

A. Melandri

Istituto Nazionale di Astrofisica–Osservatorio Astronomico di Brera, Via E. Bianchi 46, I-23807 Merate, Italy.

J. Moldon

Electronic Multi-Element Radio Linked Interferometer Network/Very Long Baseline Interferometry (e-MERLIN/VLBI) National Facility, Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Manchester, UK.

L. Nava

Istituto Nazionale di Astrofisica–Osservatorio Astronomico di Brera, Via E. Bianchi 46, I-23807 Merate, Italy.

A. Perego

Sezione di Milano Bicocca, Istituto Nazionale Fisica Nucleare (INFN), Piazza della Scienza 3, 20126 Milano, Italy.

M. A. Perez-Torres

Instituto de Astrofísica de Andalucía–Consejo Superior de Investigaciones Científicas (CSIC), Glorieta de la Astronomía s/n, E-18008, Granada, Spain.Departamento de Física Teórica, Facultad de Ciencias, Universidad de Zaragoza, E-50019, Spain.

C. Reynolds

Commonwealth Scientific and Industrial Research Organization (CSIRO) Astronomy and Space Science, PO Box 1130, Bentley WA 6102, Australia.

R. Salvaterra

Istituto Nazionale di Astrofisica, Istituto di Astrofisica Spaziale e Fisica cosmica (IASF), via E. Bassini 15, 20133 Milano, Italy.

G. Tagliaferri

Istituto Nazionale di Astrofisica–Osservatorio Astronomico di Brera, Via E. Bianchi 46, I-23807 Merate, Italy.

T. Venturi

Istituto Nazionale di Astrofisica–Istituto di Radioastronomia, via Gobetti 101, I40129, Bologna, Italia.

S. D. Vergani

Galaxies, Etoiles, Physique et Instrumentation (GEPI) Observatoire de Paris, CNRS UMR 8111, Meudon, France.

M. Zhang

Xinjiang Astronomical Observatory, Chinese Academy of Sciences, 150 Science 1-Street, Urumqi 831001, China.Key Laboratory for Radio Astronomy, Chinese Academy of Sciences, 2 West Beijing Road, Nanjing 210008, China.