TITLE:   GCN CIRCULAR
NUMBER:  11150
SUBJECT: GRB 100725B: Mondy optical upper limit
DATE:    10/08/27 14:11:49 GMT
FROM:    Alina Volnova at SAI MSU  <alinusss@gmail.com>

E. Klunko (ISTP), A. Volnova(SAI MSU), A. Pozanenko (IKI) report on
behalf of larger GRB follow-up collaboration:

We observed the field of the Swift GRB 100725B (Baumgartner et al.,
GCN 10983) with AZT-33IK telescope of Sayan observatory (Mondy) on
Jul.25 between (UT) 16:36 - 20:18 under variable weather conditions
and mean seeing ~2.0". In the stacked image of the best of 36 images
we do not detect any sources in enhanced XRT error circle (Goad et al.
GCN 10986). The upper limit (3 sigma) of the stacked image based on
SDSS-DR7 field stars is the following:

t-t0,d	filter	exp.,s	uplim
0.31128	R	36*90	21.3