[vsnet-grb-info 8179] GRB 090726: optical transient candidate

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9709
SUBJECT: GRB 090726: optical transient candidate
DATE:    09/07/27 03:50:30 GMT
FROM:    Vladimir Sokolov at SAO RAS  <sokolov at sao.ru>

A. Moskvitin, T. Fatkhullin & A. Valeev
(SAO-RAS Niznijh Arkhyz, Russia),
on behalf of a larger colaboration, report:

We have observed the field of GRB090618
(Page et al., GCN 9706) with the 1-m telesecope
of the SAO RAS in Caucasus. Within the XRT error
circle (Page et al., GCN 9707) we detected one
object which not present in the DSS. The object's
coordinates are:
    R.A. (J2000.0) = 16:34:43.044
    DEC. (J2000.0) = +72:53:04.82
with uncertainty about 0.5 arcsec. Using
the USNO A2.0 star 1628-0121951 (R2=14.51)
as a calibration we estimated the object's
brightness as following:

   R_mag         exp.(sec)       mid.time
                             (sec after the trigger)
18.26 +/- 0.05     60              2126
18.39 +/- 0.05     60              2252
18.33 +/- 0.05     60              2344
18.71 +/- 0.05    120              3183
18.97 +/- 0.05    180              4296
19.17 +/- 0.06    180              5492
19.28 +/- 0.07    240              6089
19.55 +/- 0.12    300              6824

According to its variability we concluded that
the detected object is the OT of the GRB090726.

Further analysis are ongoing.

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