[vsnet-grb-info 20831] GRB 180705A: RTT150 optical upper limit

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22929
SUBJECT: GRB 180705A: RTT150 optical upper limit
DATE:    18/07/08 16:42:54 GMT
FROM:    Rodion Burenin at IKI, Moscow  <rodion at hea.iki.rssi.ru>

I. Bikmaev, E. Irtuganov, N. Sakhibullin (KFU/AST),
R. Burenin, M. Pavlinsky, R. Sunyaev (IKI),
I. Khamitov, S. Ozdemir (TUG), E. Gogus (Sabanci Uni.)

report:

We observed the field of GRB 180705A (Stamatikos et al., GCN 22902)
with the Russian-Turkish 1.5-m optical telescope (RTT150, Bakirlitepe,
TUBITAK National Observatory, Turkey) using the TFOSC instrument.

We obtained series of Rc exposures in July 05, 2018 (6 frames x 600
sec, UT = 19:12 - 20:19), ~ 4 hours after the burst. Within enhanced
Swift-XRT position (Goad et al., GCN 22906) we have not detected any
object down to Rc =~ 23.5 mag in the combined image (calibrated
against SDSS secondary standard stars).  Our result confirms OT
non-detections as published in other GCNs (Lipunov et al., GCN 22904,
Watson et al., GCN 22911, Breeveld et al., GCN 22912, Mazaeva et al.,
GCN 22913).