[vsnet-grb-info 4036] GRB061121: optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  5850
SUBJECT: GRB061121: optical observations
DATE:    06/11/24 17:54:56 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

Yu. Efimov, V. Rumyantsev (CrAO), A. Pozanenko (IKI) on behalf of larger GRB
follow up collaboration report:

We observed error box of GRB061121 (Page et al., GCN 5823)  with Shajn 2.6m
telescope of CrAO. A set of  exposures was taken on Nov. 22 in B,R under
poor weather conditions and  a set of  22x180 s R-exposures on Nov.23.  The
afterglow (Page et al., GCN 5823; Yost et al., GCN 5824) is not detected in
a single images of 60 s exposure on Nov.22 and clearly visible on a single
images of 180 s on Nov. 23. For the analysis of Nov. 22 observation we take
the best single image while for Nov.23 observation we use two combined
images. Preliminary data reduction of the observations is following:

Mid time   Exposure,  R_mag,    Lim_mag (3 sigma)
(UT)          s

Nov. 22.1309   1x60     n/d          20.60
Nov. 23.1040  11x180  21.37 +/- 0.05 23.55
Nov. 23.1329  11x180  21.47 +/- 0.06 23.49

Above estimations are based on  USNO A2.0 star RA=09 48 57.46   Dec=-13 13
20.10   R=17.30. The combine image of  the last epoch can be found in
http://grb.rssi.ru/GRB061121/GRB061121_20061122_ZTSh_R

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