GCN Circular 10275
Subject
GRB 091208B: GAO 150cm telescope Optical Observation
Event
Date
2009-12-10T08:51:42Z (16 years ago)
From
Kenzo Kinugasa at Gunma Astro. Obs/Japan <kinugasa@astron.pref.gunma.jp>
K. Kinugasa, S. Honda, H. Takahashi, H. Taguchi, O. Hashimoto
(Gunma Astronomical Observatory) report:
The position of GRB 091208B (Pagani et al., GCN 10256) was observed
with the 150 cm telescope of Gunma Astronomical Observatory.
Starting at 10:21:09 UT on Dec.8 ( 0.52 hours after the trigger),
both Rc and Ic frames were acquired for sets of 3 x 2-min and
5 x 5-min exposures.
We detected the optical counterpart (e.g., de Ugarte Postigo et al.,
GCN 10255; Yoshida et al. GCN 10258) in all frames. We estimated the
Rc and Ic magnitudes relative to USNO-B1.0 R2 and I magnitudes,
respectively.
mid-UT T0+(d) exp mag.
-----------------------------------------------------
10:50:45 0.01796 3x2min, 5x3min Rc=18.8+-0.1
11:07:20 0.02273 3x2min, 5x3min Ic=18.4+-0.1
-----------------------------------------------------
The R magnitude is consistent with the fading trend of a power-law
slope of ~0.7 from the other optical observations (e.g. Cano et al.
GCN 10262; Xu et al. GCN 10269; Nakajima et al. GCN 10260).