GCN Circular 13636
Subject
GRB 120811C: RTT150 optical observations
Date
2012-08-13T17:29:30Z (12 years ago)
From
Rodion Burenin at IKI, Moscow <rodion@hea.iki.rssi.ru>
A. Galeev (Kazan Federal University), I. Khamitov (TUG),
I. Bikmaev, N. Sakhibullin (Kazan Federal University),
R. Burenin, M. Pavlinsky, R. Sunyaev (IKI),
Z. Eker (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.)
report:
We continued the observations of the field of the Swift-BAT GRB
120811C (Barlow et al. GCN 13622, Galeev et al., GCN 13626) with
Russian-Turkish 1.5-m telescope (RTT150, Bakirlitepe, TUBITAK National
Observatory, Turkey). The second epoch observations were started at
12 Aug, 18:38 UT, i.e. approximately 27.05 hours after the burst. We made
a serie of 300s images in R using TFOSC instrument.
The afterglow was clearly detected in the combined image. Using
USNO-B1 stars as reference, we estimated the afterglow magnitude as
m_R=22.3+-0.2.
Fitting this point together with the data from RTT150 first epoch
observations (Galeev et al., GCN 13626), gives the power law decay
with index alpha = 1.04 +- 0.05, consistent with late time decay in
X-rays, as it was observed with XRT (Evans et al., GCN 13630).
When all RTT150 data are compared with the data of MASTER telescopes
(Denisenko et al., GCN 13623, Ivanov et al., 13635), the power law
break at few hours time scale is found, approximately consistent with
the position of second break observed in X-rays with XRT (Evans et
al., GCN 13630). However, better cross-calibration between RTT and
MASTER photometry should be done for more reliable light curve
modelling.
The light curve and direct images of the field can be found at:
http://hea.iki.rssi.ru/grb/120811c/indexeng.html