A. Stefanescu (1), A. Slowikowska (2)(3), G. Kanbach (1), S. Duscha (1),
F. Schrey (1), H. Steinle (1), Z. Ioannou (4) of the OPTIMA-Burst Team
report the following:
(1)=MPE, Garching, (2)=FORTH, Heraklion (3)=NCAC, Torun (4)=Univ. of Crete
"OPTIMA-Burst at the 1.3m Skinakas Observatory, of the University of
Crete, Greece slewed to the Swift BAT-errorcircle of GRB 070610 (GCN
Circ 6489, C. Pagani et al.) and started observations at 20:53:23UT (57s
after the burst, 28s after the notice).
We detected a faint transient in the BAT errorcircle. The transient was
marginally detected as 19+-0.4 mag in our first 10s white-light image,
and was not detected in subsequent CCD frames. The position of the
transient is inside the XRT error-circle (GCN 6490, C. Pagani et al.).
At 20:57:19 (293s after the burst) observations with the fibre-fed,
single-photon-counting high-time-resolution main instrument of
OPTIMA-Burst started. A quick-look analysis of this data binned to 1s
resolution indicates that the source is barely detectable (below the 2
sigma level) until 21:00:22 (476s after the burst). At that time the
source showed a flaring activity of about 7.5 sigma above the background
level. The activity lasted about 80s and consisted of three to four
overlapping spikes and a slow decay.
Further analysis is in progress."
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