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GCN Circular 3853

GRB050820A: RTT150 optical observations
2005-08-22T12:40:21Z (19 years ago)
Irek Khamitov at TUG <>
I. Bikmaev, A. Galeev, N. Sakhibullin (KSU/AST),
R. Burenin, M. Pavlinsky, R. Sunyaev (IKI),
I. Khamitov, Z. Aslan (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.),


      We have observed the OT of GRB 050820A (GCN 3829) with the
Russian-Turkish 1.5-m telescope (Bakirlitepe, TUBITAK National
Observatory, Turkey) in two consequative nights .
      We made a series of exposures in Rc between UT 18:35 - 22:15, August 
20, 2005, and in BRcIc between UT 22:46-01:15, August 21/22, 2005. 
Moonlight produced variable background in all images for both nights. The 
afterglow is clearly detected in all bands. Using  Henden's stars (GCN 3845)
present in the frames,  we estimated the magnitudes as follow:

   t-t0 		Band 	mag      merr   exptime
(hours, midtime)                       (sec,total)
18.05 		Rc 	19.48 +/- 0.01   900
41.42 		Rc 	20.38 +/- 0.05   1800
40.93 		B 	21.00 +/- 0.06   1800
41.55 		Ic 	19.83 +/- 0.07   1800

    On the basis of our Rc data, we estimeted an alpha index of power-law
decay for the observed period as ~ -1.0.

The JPG-images  of BRcIc and color combined image are available at:

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