[vsnet-grb-info 14547] GRB 140215A: RAPTOR Observations During Gamma-Ray Emitting Interval

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15861
SUBJECT: GRB 140215A: RAPTOR Observations During Gamma-Ray Emitting Interval
DATE:    14/02/19 15:35:54 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 586680 (Markwardt, et al., GCN 15837).  Our narrow-field
instruments in Los Alamos, NM, began imaging at 04:07:37.21 UT,
26.9 seconds after the BAT trigger time.  We do not detect the counterpart
in our three initial images, with limiting magnitudes near 14.0.  The
counterpart then rises above our detection limit and reaches peak brightness
at magnitude 13.5 around T-Tbat=90s.  The counterpart then plateaus for
a period of about 50 seconds before beginning a power-law decay.  Our
unfiltered observations were calibrated to the USNO-B1 R-band.  The following
table summarizes some of our early observations.

t-mid(s)    exp(s)    mag     error
------------------------------------
29.45       5      >14.0
56.85       5      13.8287    0.033
83.85       5      13.5381    0.011
128.95      10     13.5608    0.008
283.35      10     14.3725    0.024
470.75      30     14.9185    0.020