TITLE:   GCN CIRCULAR
NUMBER:  13760
SUBJECT: GRB 120911A: optical upper limit CrAO
DATE:    12/09/13 07:18:31 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

V. Rumyantsev, N.Pit' (CrAO), A. Pozanenko (IKI) report on behalf of  larger 
GRB  follow-up collaboration:

We observed the field of  the Swift GRB 120911A (Cannizzo  et al., GCN 
13744) with  AZT-11 telescope of CrAO observatory  starting on  Sep. 11 (UT) 
21:10:38.  We took  several images in R-filter of 180 s exposure.  Within 
enhanced XRT afterglow position (Beardmore et al., GCN 13748) we do not 
detect any new object.   A preliminary  photometry of co-added frame is 
based  on the USNO-B1.0 (R2)  nearby  stars is following:

T0+,        Filter   Exposure,   OT,         UL (3 sigma)
mid, d                 (s)

0.6130     R        20x180       n/d          20.9