GCN Circular 9190
Subject
GRB 090418A: RTT150 optical observations
Event
Date
2009-04-22T11:07:11Z (17 years ago)
From
Rodion Burenin at IKI, Moscow <rodion@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 optical afterglow of GRB 090418A (Chornock et al., GCN 9148, Mangano et
al., GCN 9149) was observed with Russian-Turkish 1.5-m telescope (RTT150,
Bakirlitepe, TUBITAK National Observatory, Turkey) under moderate
transparences. We obtained series of 600s exposures in BVRc filters,
centered at April 18, 23:40 UT, i.e. 0.52 days after the burst.
The afterglow is clearly seen at combined R image, and marginally detected
at combined B,V frames.
Using the same calibration star USNO-B1.0 1234-0288651 as Pavlenko et
al. (GCN 9179), we estimate the following magnitudes of OT:
Filter, Exposure, mag., err.
(s)
B 3x600 23.5 limit
V 3x600 22.7 limit
R 4x600 22.1 +/- 0.1
We made also series of 3x900 sec exposures in Rc filter centered on April
20, 23:00, i.e. 2.5 days after the burst. The afterglow was not detected on
the combined frame with a limit R=23.3 mag
RTT150 finding chart (Rc) can be found at:
http://hea.iki.rssi.ru/grb/090418a/indexeng.html