[vsnet-grb-info 12621] GRB 121108A: optical upper limit

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  13981
SUBJECT: GRB 121108A: optical upper limit
DATE:    12/11/21 17:12:37 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

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

We observed the field of  the Swift GRB 121108A (Ukwatta et al., GCN 
13952) with  AZT-11 telescope of CrAO observatory  starting on  Nov. 08 
(UT) 18:07:04. We took  several images in R-filter of 180 s exposure. 
Within enhanced XRT afterglow position (Beardmore et al., GCN 13959) we 
do not detect any new object.   A 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)

0.02395     R        10x180      n/d         18.9