[vsnet-grb-info 14501] GRB 140209A: Early RAPTOR Optical Detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15815
SUBJECT: GRB 140209A: Early RAPTOR Optical Detection
DATE:    14/02/10 19:32:06 GMT
FROM:    James Wren at LANL  <jwren at nis.lanl.gov>

J. Wren, W.T. Vestrand, P. Wozniak, and H. Davis,
of Los Alamos National Laboratory report:

The RAPTOR network of robotic optical telescopes made follow-up observations
of Swift trigger 586071 (Cenko, et al., GCN 15808).  Our narrow-field
instruments in Los Alamos, NM, began imaging at 07:31:24.33 UT,
26.5 seconds after the BAT trigger time.  We clearly detect the optical
counterpart (Perley, et al., GCN 15809).  Our first image at Tmid-Tbat=29.0s
shows the counterpart at an unfiltered magnitude of 14.43+-.04.  The
counterpart fades steadily to mag 15.50+-.08 by Tmid-Tbat=65.4s.  Our
unfiltered observations were calibrated to the USNO-B1 R-band.