[1] Univ North Texas, Dept Phys, Denton, TX 76203 USA
[2] Univ Wyoming, Dept Phys & Astron, Laramie, WY 82071 USA
[3] Univ Nacl La Plata, Fac Ciencias Astron & Geofiis, B1900FWA, La Plata, Argentina
[4] CONICET UNLP, CCT La Plata, Inst Astrofis La Plata, B1900FWA, La Plata, Argentina
[5] Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA
[6] Penn State Univ, Inst Gravitat & Cosmos, University Pk, PA 16802 USA
[7] Penn State Univ, Dept Phys, Davey Lab 104, University Pk, PA 16802 USA
[8] Univ Western Ontario, Dept Phys & Astron, 1151 Richmond St, London, ON N6C 1T7, Canada
[9] Univ Arizona, Steward Observ, 933 N Cherry Ave, Tucson, AZ 85721 USA
[10] Univ Chile, Dept Astron, Casilla 36D, Santiago, Chile
[11] Univ Nevada, Dept Phys, Reno, NV 89557 USA
[12] Drexel Univ, Dept Phys, 32 S 32nd St, Philadelphia, PA 19104 USA
[13] Vanderbilt Univ, Dept Phys & Astron, 6301 Stevenson Ctr Ln, Nashville, TN 37235 USA
[14] Univ Illinois, Dept Astron, Urbana, IL 61801 USA
[15] Univ Illinois, Natl Ctr Supercomp Applicat, Urbana, IL 61801 USA
[16] Princeton Univ, Dept Astrophys Sci, Princeton, NJ 08544 USA
[17] Univ Texas Austin, Univ Texas Astron Dept, C1400,1 Univ Stn, Austin, TX 78712 USA