1. Astrophysics Division, National Institute for Space Research (INPE), Av. Dos Astronautas,1758 São Jose dos Campos, SP, Brazil
2. Physics Division, Eduardo Mondlane University (UEM), Av. Julius Nyerere 1569, Maputo, Mozambique
3. SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK