[vsnet-grb-info 7636] GRB 090418B: RTT150 optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9191
SUBJECT: GRB 090418B: RTT150 optical observations
DATE:    09/04/22 13:44:41 GMT
FROM:    Rodion Burenin at IKI, Moscow  <rodion at hea.iki.rssi.ru>

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

report:

The field of GRB 090418B (Copete et al., GCN 9159) was observed with
Russian-Turkish 1.5-m telescope (RTT150, Bakirlitepe, TUBITAK National
Observatory, Turkey). We obtained series of 3x300s exposures in Rc filter,
centered on April 19, 01:04 UT, i.e. 16 hours after the burst.  In addition,
a second epoch of 4x300 sec exposures was obtained in Rc filter on April 20,
0:17 UT.

Similarly to Guidorzi et al. (GCN 9176), Afonso et al. (GCN 9178), Nissinen
et al. (GCN 9181) we do not detect any obvious fading optical source inside
the BAT error circle. The upper limit for the first epoch of our
observations is Rc > 22.7 mag.