TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  5173
SUBJECT: GRB 060526: RTT150 optical observations
DATE:    06/05/27 05:16:31 GMT
FROM:    Rodion Burenin at IKI, Moscow  <rodion@hea.iki.rssi.ru>

I. Khamitov (TUG), I. Bikmaev, N. Sakhibullin (KSU/AST),
Z. Aslan (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.),
R. Burenin, M. Pavlinsky, R. Sunyaev (IKI)

report:

We observed the field around position of optical counterpart (Campana et
al. GCN 5162; French & Jelinek GCN 5165; Rykoff et al. GCN 5166) of
GRB060526 (Swift trigger 211957) with Russian-Turkish 1.5-m telescope
(RTT150, Bakirlitepe, TUBITAK National Observatory, Turkey), starting at
May. 27, 00:56UT, i.e. ~5.45 hours after the burst. A series of frames
was taken (200*30s exposures in R, 5*300 exposures in B and V).

The power-law decay index in Rc is approximately -1.2 between 5.61 and
8.88 hours after the burst. Using USNO-B1 star (RA=15:31:18.6, DEC=+00
17 34.9, R2MAG=16.35) we estimate the following Rc magnitudes for the
OT:

   t-t0  m_R     err
   5.61	 18.840  0.02
   5.99  18.893  0.02
   6.10  18.924  0.03
   6.20  18.908  0.03
   6.52  19.029  0.03
   6.63  19.051  0.03
   6.74  18.977  0.03
   7.04  19.133  0.04
   7.15  19.141  0.03
   7.26  19.128  0.03
   7.58  19.173  0.03
   7.69  19.291  0.03
   7.80  19.283  0.04
   8.12  19.243  0.04
   8.23  19.409  0.04
   8.34  19.342  0.04
   8.45  19.406  0.05
   8.56  19.290  0.05
   8.66  19.270  0.04
   8.77  19.377  0.06
   8.88  19.477  0.06

The Rc lightcurve can be found at:

http://hea.iki.rssi.ru/grb/060526/lc.jpg

This message may be cited.