GCN Circular 12645
Subject
GRB 111209A: PROMPT optical observations of early afterglow
Date
2011-12-09T22:54:13Z (12 years ago)
From
Melissa Nysewander at UNC-Chapel Hill <mnysewan@unc.edu>
M. Nysewander, J. Haislip, A. LaCluyze, K. Ivarsen, D. Reichart, J. Moore, A. Trotter, R. Egger, A. Foster, A. Oza, T. Cromartie, E. Speckhard, and J. A. Crain report:
Skynet observed the field of GRB 111209A with the PROMPT telescopes located at CTIO in Chile. Observations began in VRI at 378 sec (34 sec after the alert) and lasted for 13.2 min before the source set below PROMPT's elevation constraints.
We detect the fading afterglow discovered by Hoversten et al. (GCN 12632). Preliminary calibration to USNO B1.0 catalog stars yields the follow initial detections:
Start Time t - t0 Exp Telescope Filter Mag Err
07:18:28 380s 40s Prompt5 I 18.0 0.20
07:18:31 383s 40s Prompt4 R 18.3 0.30