TITLE: GCN CIRCULAR NUMBER: 15218 SUBJECT: GRB 130912A: Skynet DSO-14/Yerkes-41/PROMPT-CTIO observations DATE: 13/09/12 17:07:49 GMT FROM: Adam S. Trotter at UNC-Chapel Hill/PROMPT/Skynet A. Trotter, D. Reichart, J. Haislip, A. LaCluyze, A. B. Smith, D. Caton, L. Hawkins, V. Hoette, K. Cudworth, D. Harper, R. Kron, T. Linder, R. Russell, E. Struble, T. Berger, H. T. Cromartie, R. Egger, A. Foster, N. Frank, K. Ivarsen, M. Maples, J. Moore, M. Nysewander, and J. A. Crain report: Skynet observed the Swift/XRT localization of GRB 130912A (D'Elia et al., GCN 15212, Swift trigger 570465) with the 14" telescope at the Appalachian State University Dark Sky Observatory (DSO-14) in NC, USA (R and I bands), the 41" telescope of Yerkes Observatory in WI, USA (r' and i' bands), and with four 16" telescopes of the PROMPT array at CTIO, Chile (B, V, R, and I bands). Starting at 2013-09-12, 08:47 UT and continuing until 10:26 UT (t=12m-111m post-trigger), Skynet took a total of 72 160s exposures. In stacked images, we do not detect an optical source in any band in or near the XRT error circle. Our 3-sigma limiting magnitudes are tabulated below: ================================== tmid scope expos fil limit ================================== 21m DSO-14 2x160s I >18.7 24m DSO-14 2x160s R >19.6 61m Prompt5 10x160s I >20.6 61m Prompt4 10x160s R >21.0 61m Prompt1 10x160s V >21.3 61m Prompt3 10x160s B >21.1 63m Y-41 11x160s i' >21.6 60m Y-41 9x160s r' >21.9 66m Y-41 8x160s g' >21.8 ================================== BVRI magnitudes are in the Vega System, and g'r'i' magnitudes are in the AB system, calibrated to 4 APASS stars in the field. Magnitudes have not been corrected for line-of-sight Milky Way dust extinction, with expected E(B-V)=0.28 (Schlegel et al. 1998). No further Skynet observations are scheduled.