1. Department of Physics, University of Helsinki , Gustaf Hällströmin katu 2, FI-00014 Helsinki , Finland
2. Center for Computational Astrophysics, Flatiron Institute , 162 5th Avenue, New York, NY 10010 , USA
3. International Centre for Radio Astronomy Research, University of Western Australia , 7 Fairway, Crawley, WA 6009 , Australia
4. ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D)
5. Lorentz Institute for Theoretical Physics, Leiden University , PO Box 9506, NL-2300 RA Leiden , the Netherlands
6. Leiden Observatory, Leiden University , PO Box 9513, NL-2300 RA Leiden , the Netherlands
7. Institute for Astronomy, University of Edinburgh , Royal Observatory, Edinburgh EH9 3HJ , UK
8. Department of Physics and Astronomy, University of the Western Cape , Bellville, Cape Town 7535 , South Africa
9. Department of Physics, University of Connecticut , 196 Auditorium Road, U-3046, Storrs, CT 06269 , USA
10. Columbia Astrophysics Laboratory, Columbia University , 550 West 120th Street, New York, NY 10027 , USA