1. Max-Planck-Institut für Astrophysik , D-85741 Garching b. München , Germany
2. Center for Interdisciplinary Exploration & Research in Astrophysics (CIERA), Physics & Astronomy, Northwestern University , Evanston, IL 60202 , USA
3. Department of Physics and Astronomy, College of Charleston , Charleston, SC 29424 , USA
4. Kavli Institute for Theoretical Physics, Kohn Hall, University of California , Santa Barbara, CA 93107 , USA
5. Canadian Institute for Theoretical Astrophysics , 60 St George Street, Toronto, ON M5S 3H8 , Canada
6. Nicolaus Copernicus Astronomical Center , ul. Bartycka 18, PL-00-716 Warsaw , Poland