1. Anton Pannekoek Institute for Astronomy, University of Amsterdam , Science Park 904, NL-1098 XH Amsterdam , the Netherlands
2. Leiden Observatory, Leiden University , PO Box 9513, NL-2300 RA Leiden , the Netherlands
3. Astrophysics, University of Oxford , Denys Wilkinson Building, Keble Road, Oxford OX1 3RH , UK
4. Naval Research Laboratory, Remote Sensing Division , 4555 Overlook Avenue SW, Washington, DC 20375 , USA
5. Department of Physics, University of Warwick , Coventry, West Midlands CV4 7AL , UK
6. Large Binocular Telescope Observatory, University of Arizona , 933 North Cherry Avenue, Tucson, AZ 85721 , USA
7. Steward Observatory and Department of Astronomy, University of Arizona , 933 North Cherry Avenue, Tucson, AZ 85721 , USA
8. Minnesota Institute for Astrophysics, University of Minnesota , 116 Church Street SE, Minneapolis, MN 55455 , USA
9. Department of Astronomy and Astrophysics, University of California , Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 , USA
10. Leibniz Institute for Astrophysics Potsdam (AIP) , An der Sternwarte 16, D-14482 Potsdam , Germany
11. Center for Astrophysics | Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138 , USA