1. Department of Physics, McGill University, Montréal, Quebec H3A 2T8, Canada
2. School of Mathematics, Statistics, and Computer Science, University of KwaZulu–Natal, Durban 4000, South Africa
3. Department of Astronomy, University of California, Berkeley, California 94720, USA
4. Canadian Institute for Theoretical Astrophysics, Toronto, Ontario M5R 2M8, Canada
5. South African National Space Agency, Hermanus 7200, South Africa
6. Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
7. School of Chemistry and Physics, University of KwaZulu–Natal, Durban 4000, South Africa