TITLE:   GCN CIRCULAR
NUMBER:  15859
SUBJECT: GRB 140213A: Continued Skynet R-COP/PROMPT Detections of a Rebrightening Optical Afterglow
DATE:    14/02/18 18:25:08 GMT
FROM:    Adam S. Trotter at UNC-Chapel Hill/PROMPT/Skynet  <atrotter@physics.unc.edu>

A. Trotter, J. Haislip, D. Reichart, A. LaCluyze, A. Verveer, T. Spuck, 
A. Foster, N. Frank, K. Ivarsen, J. Moore, M. Nysewander, R. Beauchemin, 
T. Berger, M. Carroll, H. T. Cromartie, R. Egger, M. Hinckle, A. 
Ireland, M. Maples, L. Scott, and J. A. Crain report:

Skynet continued observing the Swift-BAT localization of GRB 140213A 
(Holland et al., GCN 15825, Swift trigger 586569) with the 14-inch R-COP 
telescope at Perth Observatory, Australia, and with 4 16-inch telescopes 
of the PROMPT array at CTIO, Chile.  Previous observations with R-COP 
began at 59s and continued until 92m post-trigger (Trotter et al., GCN 
15828). Observations resumed with PROMPT-CTIO at t=5.5h, and continued 
at R-COP and PROMPT-CTIO until t=32h, with a total of ~600x160s new 
exposures in the BVRI bands.

We continue to detect an uncatalogued optical source in all bands at the 
position of the source detected by the Swift UVOT (Siegel & Holland, GCN 
15826). The source faded from R=14.3 at t=113s to R=17.8 at t=73m, 
bottomed out at R=19.0 at t~6h, and then rebrightened to R=18.6 by 
t=23h.  Flattening or rebrightening of the light curve is observed in 
all four bands.

An updated light curve is at:
http://www.skynet.unc.edu/grb/grb140213a_2.png

Magnitudes are in the Vega system, calibrated to ten APASS-DR7 stars in 
the field, and have not been corrected for the Galactic foreground 
extinction corresponding to E(B-V)=0.07 (Schlegel et al. 1998).

Skynet observations are ongoing.