1. Centre for Space Research, North-West University , Potchefstroom 2520 , South Africa
2. Center for Computational Astrophysics, Flatiron Institute , 162 5th Ave, New York, NY 10010 , USA
3. Centre for Astrophysics Research, Department of Physics, Astronomy and Mathematics, University of Hertfordshire , Hatfield AL10 9AB , UK
4. National Institute for Theoretical and Computational Sciences (NITheCS) , Potchefstroom 2520 , South Africa
5. School of Physics and Astronomy, University of Edinburgh , Edinburgh EH9 3HJ , UK
6. Department of Physics and Astronomy, University of the Western Cape , Bellville 7535 , South Africa
7. Department of Physics and Astronomy, University of Victoria , Victoria BC V8P 5C2 , Canada
8. Departamento de Física Teórica , M-8, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid , Spain
9. Centro de Investigación Avanzada en Física Fundamental (CIAFF), Universidad Autónoma de Madrid , Cantoblanco, E-28049 Madrid , Spain