GCN Circular 14490
Subject
GRB 130427A optical time series
Event
Date
2013-04-28T13:46:40Z (13 years ago)
From
AAVSO GRB Network at AAVSO <matthewt@aavso.org>
Patrick Wiggins (Stansbury Park, Utah, United States) reports the following
optical observations of the error box of GRB 130427A (GCN Circ #14448,
Maselli et al.) to the AAVSO International High Energy Network:
P. Wiggins reports three hours of time-series photometry of the bright GRB
130427A (Maselli et al., GCN Circ. #14448; Elenin et al., GCN Circ. #
14450). Wiggins used a 0.35-m C-14 f/5.5 telescope with an SBIG ST-10XME
camera and clear filter located in Stansbury Park, Utah. Observations
commenced 2013 April 27 08:05:12 UT -- less than 20 minutes post trigger
-- and continued through 11:10:06 UT. The first four observations were
made with 60-second exposure times, which were found to be close to
saturation; subsequent exposure times were 30 seconds. The transient was
detected by visual inspection of the first frame, and found to be very
bright. Time-series observations were begun immediately.
Thirty-three images of the field were taken, and the resulting light curve
is as follows. All magnitudes are taken with respect to the comparison
star GSC 01984-00021, which has an r-magnitude of 12.553 (APASS DR7,
http://www.aavso.org/apass ); the resulting magnitudes should be
interpreted as through a clear filter with r'-band zero point. Note that
the first four magnitudes with integration times of 60 seconds may be
saturated. All times are given as the mid-point of the exposure, UT on
2013 April 27, and T(0)+h is hours since trigger (07:47:57 UT):
Obs. UT T(0)+h Exp. time magn. mag.err.
08:05:41.529 0.296 60.00 13.108 0.006
08:06:57.779 0.317 60.00 13.194 0.007
08:14:16.467 0.439 60.00 13.557 0.009
08:27:07.951 0.653 60.00 13.995 0.013
08:40:35.701 0.877 30.00 14.304 0.024
08:46:36.857 0.978 30.00 14.413 0.027
08:50:51.998 1.049 30.00 14.47 0.029
08:55:17.311 1.122 30.00 14.546 0.030
09:00:52.545 1.215 30.00 14.623 0.033
09:06:26.014 1.308 30.00 14.684 0.035
09:11:59.514 1.401 30.00 14.731 0.038
09:17:33.139 1.493 30.00 14.792 0.041
09:23:06.748 1.586 30.00 14.829 0.043
09:28:40.357 1.679 30.00 14.969 0.050
09:34:18.373 1.773 30.00 14.957 0.050
09:39:51.873 1.865 30.00 14.911 0.050
09:45:25.545 1.958 30.00 15.025 0.055
09:50:59.404 2.051 30.00 15.158 0.064
09:56:32.982 2.143 30.00 15.104 0.064
10:02:06.529 2.236 30.00 15.22 0.073
10:07:40.154 2.329 30.00 15.138 0.071
10:13:13.732 2.421 30.00 15.249 0.080
10:15:01.029 2.451 30.00 15.219 0.078
10:20:47.498 2.547 30.00 15.302 0.088
10:26:21.123 2.64 30.00 15.424 0.099
10:31:54.732 2.733 30.00 15.387 0.100
10:37:28.451 2.825 30.00 15.247 0.091
10:43:02.248 2.918 30.00 15.512 0.123
10:48:35.811 3.011 30.00 15.496 0.124
10:54:09.561 3.103 30.00 15.517 0.128
10:59:43.279 3.196 30.00 15.633 0.150
11:05:19.092 3.289 30.00 15.555 0.150
11:10:20.982 3.373 30.00 15.48 0.153
The AAVSO International High Energy Network is supported through the
AAVSO Endowment Fund. We thank the Charles Curry Foundation and
NASA for past support.