1. Astrophysics, Department of Physics, University of Oxford , Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, UK
2. Department of Astronomy, University of Cape Town , Private Bag X3, Rondebosch 7701, South Africa
3. CSIRO, Space and Astronomy , PO Box 1130, Bentley, WA 6102, Australia
4. Jodrell Bank Centre for Astrophysics, Department of Physics and Astronomy, The University of Manchester , Manchester M13 9PL, UK
5. Sydney Institute for Astronomy, School of Physics, The University of Sydney , Camperdown, NSW 2006, Australia
6. AIM/CEA Paris-Saclay, Universite Paris Diderot , CNRS, F-91191 Gif-sur-Yvette, France
7. South African Astronomical Observatory , PO Box 9, Observatory 7935, South Africa
8. Department of Physics and Electronics, Rhodes University , PO Box 94, Makhanda 6140, South Africa
9. South African Radio Astronomy Observatory , 2 Fir Street, Observatory 7925, South Africa
10. Department of Physics, The George Washington University , 725 21st Street NW, Washington, DC 20052, USA
11. Astronomy, Physics and Statistics Institute of Sciences (APSIS) , 725 21st Street NW, Washington, DC 20052, USA
12. Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Brera , via E. Bianchi 46, I-23807 Merate (LC), Italy
13. National Radio Astronomy Observatory , Socorro, NM 87801, USA
14. Shanghai Astronomical Observatory, Chinese Academy of Sciences , 80 Nandan Road, Shanghai 200030, China
15. School of Astronomy and Space Science, University of Chinese Academy of Sciences , 19A Yuquanlu, Beijing 100049, China
16. Department of Astrophysics/IMAPP, Radboud University , PO 9010, NL-6500 GL Nijmegen, the Netherlands
17. Dipartimento di Fisica e Astronomia, Università degli Studi di Bologna , Via Gobetti 93/2, I-40129 Bologna, Italy
18. INAF – Istituto di Radioastronomia , Via Gobetti 101, I-40129 Bologna, Italy
19. Center for Astro, Particle and Planetary Physics, New York University Abu Dhabi , PO Box 129188, Abu Dhabi, UAE
20. Citizen Scientist, Zooniverse c/o University of Oxford , Keble Road, Oxford OX1 3RH, UK