I. Bikmaev, A.Galeev, N. Sakhibullin (KSU/AST)
I. Khamitov, Z. Aslan (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.),
R. Burenin, M. Pavlinsky, R. Sunyaev (IKI)
The field of XRT position of GRB 060203 (Swift BAT Trigger 180151,
Retter et al., GCN 4641, GCN 4644) was observed with Russian-Turkish
1.5-m telescope (RTT150, Bakyrlytepe, TUBITAK National Observatory,
Turkey) by using Andor CCD.
We made series of 30 sec exposures in Rc and V filters, and series
of 60 sec exposures in B-filter on February 04, 00:20 - 03:50 UT.
We confirm the presence of the fading optical transient found by
Malesani et al. (GCN 4645) and Genko et al. (GCN 4646) and
estimate its magnitudes (relative to R = 18.1, V = 18.7, and B = 19.6
of nearby USNO star U1575_02633321) on our co-added frames as follows:
Rc = 19.9 +-0.1 UT(mean) = 00:49 ( 54 min after the burst)
V = 22.3 +-0.3 UT(mean) = 01:33 ( 98 min )
B > 23 UT(mean) = 02:07 ( 2h 12 min)
Rc = 21.0 +-0.1 UT(mean) = 02:49 ( 2h 54 min)
V > 22.5 UT(mean) = 03:05 ( 3h 10 min)
By using our and published R magnitudes the estimated
power law decay slope is -0.90+/-0.04
The red spectrum of OT is supporting also by IR data of Bloom et al. (GCN 4648).
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