[1] Sejong Univ, Dept Astron & Space Sci, Seoul 143747, South Korea
[2] Univ Massachusetts, Dept Astron, Amherst, MA 01003 USA
[3] Inst Nacl Astrofis Opt & Electr, Puebla, Mexico
[4] Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA
[5] Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80309 USA
[6] Illinois Wesleyan Univ, Dept Phys, Bloomington, IL 61701 USA
[7] Cardiff Univ, Sch Phys & Astron, Cardiff CF24 3AA, Wales
[8] Univ Georgia, Dept Phys & Astron, Athens, GA 30602 USA