[AAVSO-HEN] GRB 070704: RTT150 optical observations

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TITLE:   GCN CIRCULAR
NUMBER:  6617
SUBJECT: GRB 070704: RTT150 optical observations
DATE:    07/07/11 10:21:38 GMT
FROM:    Alexander Mescheryakov at IKI RAN  <gardel at hea.iki.rssi.ru>

A. Meshcheryakov, R. Burenin, M. Pavlinsky, R. Sunyaev (IKI), 
Z. Tunca (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.),
I. Bikmaev, and N. Sakhibullin (KSU/AST) report:

We observed the field of GRB 070704 (Sakamoto et al., GCN 6594) with
Russian-Turkish 1.5-m telescope (RTT150, Bakyrlytepe,TUBITAK National
Observatory, Turkey). The observations consisted of a series 30-second
exposures in g',r',i' filters. , until ~1h after the burst time we
continue only r'-filter exposures. The first exposure in g' started at
20:15:13.9UT, i.e.556 s after the BAT trigger. The observations were
finished ~1.5 hour after the burst time.

In 30-second images as well as in combined images we do not detect any
new object at the revised XRT position (Godet & Sakamoto, GCN 6598) down
to following limiting magnitudes:

Filter  T_start(sec after trigger) Exp(s)  Lim    
----------------------------------------------------------------------------
  g'     556                       30      20.1    first
                                  240      21.2    combined
  r'     641                       30      20.1    first
                                 1720      22.3    combined
  i'     721                       30      20.3    first
                                  180      21.3    combined

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