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GCN Circular 12809

GRB111228A :LOAO R-band Observations
2012-01-06T02:50:13Z (13 years ago)
Yiseul Jeon at SNU/CEOU <>
Minsung Jang, Myungshin Im, Yiseul Jeon (CEOU/Seoul National Univ.), and
Yuji Urata (NCU) on behalf of a larger collaboration

We continued our observation (Jeon et al. GCN 12791) of GRB 111228A
(Ukwatta et al., GCN 12737) in R-band with a 1 m telescope at Mt. Lemmon,
Arizona, US. Data were taken at 2011-12-31 UT and 2012-01-01 UT. For both
of them, we detected the afterglow in stacked R-band images.

We used a USNO B1 star near the afterglow, USNO-B1 1083-0199833 with
R=17.28 following Klotz et al. (GCN 12746) for our photometry calibration,
and current, rough estimates are given below.

Mid-time [UT]           | Mid-time[Since BAT] | Exptime [sec] | R-magnitude

2011-12-31 08:40:25 |        64.92 hours       |    300sec X 7  | 21.5 +/-
0.28 |
2012-01-01 11:19:52 |        91.58 hours       |    300sec X 9  | 22.3 +/-
0.36 |

We thank the LOAO operator, J. Yoon for his help with these observations.
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