[vsnet-grb-info 14003] GRB 131004A: Skynet PROMPT/DSO-14 upper limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15317
SUBJECT: GRB 131004A: Skynet PROMPT/DSO-14 upper limits
DATE:    13/10/07 04:17:33 GMT
FROM:    Nathan Frank at U.North Carolina  <nrfrank at live.unc.edu>

N. Frank, A. Trotter, D. Reichart, J. Haislip, A. LaCluyze, A. Smith, D. Caton, L. Hawkins, T. Berger, H. T. Cromartie, R. Egger, A. Foster, K. Ivarsen, M. Maples, J. Moore, M. Nysewander, E. Speckhard, and J. A. Crain report:

Skynet observed the Swift/XRT localization of the field of GRB 131004A (Hagen et al., GCN 15303, Swift trigger # 573190) with four 16" telescopes of the PROMPT array at CTIO, Chile and with the 14" telescope at the Appalachian State University Dark Sky Observatory (DSO), North Carolina, starting at 2013-10-04, 23:39:35 UT and continuing until 2013-10-05, 02:21:12 UT (t=1.9-4.7h post-trigger).

Skynet took a total of 220 160s exposures simultaneously in each of the BVRI bands. In stacked images, we do not detect any uncatalogued optical source in any band at or near the reported position. The 3-sigma limiting magnitudes of our images are:

==============================================
t(mean)   telescope        band      exposures           3-sig lim mag
-------------------------------------------------------------------------
2.5h          Prompt3             B          25x160s                18.98
2.7h           Prompt1             V          32x160s                21.56
3.4h           Prompt4             R          55x160s                21.85
3.5h           Prompt5             I            50x160s                21.12
2.9h           DSO-14                I            7x160s                  18.46
==============================================

Magnitudes are in the Vega system, calibrated to five 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.