GCN Circular 12773
Subject
GRB 111228A: Liverpool Telescope Observations
Date
2011-12-29T21:14:20Z (12 years ago)
From
Carole Mundell at ARI, JMU,Liverpool <cgm@astro.livjm.ac.uk>
A. Melandri (INAF-OAB), C. Guidorzi (U. Ferrara), C. G. Mundell (Liverpool JMU)
and N. R. Tanvir (U. Leicester), on behalf of a large collaboration report:
"We observed the optical afterglow of GRB 111228A (Ukwatta et al., GCN
12737) with the 2-m Liverpool Telescope, starting at 02:55 UT on 2011 December 29. We
took a sequence of images in Br'i' bands, with exposure time of 300s for each
individual frame.
We clearly detect the optical afterglow in all individual images. In
stacked frames we find the following magnitudes for the OT:
Mid time from Total Exp Filter Magnitude
trigger (hr) (s)
--------------------------------------------------
12.08 4x300 r' 19.68 +- 0.06
13.28 3x300 r' 19.89 +- 0.09
12.54 5x300 i' 19.57 +- 0.05
11.34 4x300 B 19.71 +- 0.08
12.96 4x300 B 19.79 +- 0.11
--------------------------------------------------
The magnitudes are calibrated against nearby SDSS-5 (r' and i' bands) and
USNO-B1.0 (B band) field stars and are not corrected for the Galactic
extinction.
This message may be cited."