1. Department of Astronomy, University of Maryland , College Park, MD 20742, USA
2. Astrophysics Science Division, NASA Goddard Space Flight Center , 8800 Greenbelt Rd, Greenbelt, MD 20771, USA
3. Department of Astronomy and Astrophysics, The Pennsylvania State University , 525 Davey Lab, University Park, PA 16802, USA
4. Lomonosov Moscow State University, SAI, Physics Department , Universitetskiy Pr., 13, Moscow 119234, Russia
5. Istituto Nazionale di Ricerche Metrologiche – Torino , Strada delle Cacce 91, I-10135 Torino, Italy
6. INAF – Istituto di Radioastronomia – Bologna , Via Gobetti 101, I-40129 Bologna, Italy
7. School of Physics and Astronomy & Institute for Gravitational Wave Astronomy, University of Birmingham , Birmingham B15 2TT, UK
8. School of Earth and Space Exploration, Arizona State University , Tempe AZ 85287, USA
9. Perimeter Institute for Theoretical Physics , 31 Caroline St. N., Waterloo, ON, N2L 2Y5, Canada
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), The George Washington University , Washington, DC 20052, USA
12. Joint Space-Science Institute, University of Maryland , College Park, MD 20742, USA
13. Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA
14. University of Tampa, Department of Chemistry, Biochemistry, and Physics , 401 W. Kennedy Blvd, Tampa, FL 33606, USA
15. Observatorio Astronomico Felix Aguilar (OAFA) , Avda Benavides s/n, Rivadavia, El Leonsito, Argentina
16. Instituto de Astrofisica de Canarias , Via Lactea, E-38200 La Laguna, Tenerife, Spain
17. South African Astronomical Observatory , PO Box 9, Observatory Road, Observatory 7935, Cape Town, South Africa