[vsnet-grb-info 17464] GRB 151228B: AbAO optical upper limit

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18891
SUBJECT: GRB 151228B: AbAO optical upper limit
DATE:    16/01/18 21:23:00 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

E. Mazaeva (IKI), R. Inasaridze (AbAO), V. Ayvazian (AbAO), A. Volnova 
(IKI), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger 
GRB follow-up collaboration:

We observed the field of the Swift  GRB 151228B (Lien et  al., GCN 
18739) with AS-32 (0.7m) telescope of Abastumani Observatory starting on 
Dec. 29 (UT) 14:38:28.  We do not detect any source within
enhanced XRT error circle (Goad et al., GCN 18743):

Date       UT start     t-T0          Filter Exp.    UL(3 sigma)
            (mid, days)                       (s)

2015-12-29 14:38:28     0.69297       None  35*120   22.1

The photometry is based on nearby SDSS-DR9 stars:
SDSS-DR9_id             R_Lupton
J225738.02+080336.8 18.18
J225747.18+080340.7 16.86
J225736.71+080628.4 17.72
J225752.89+080438.1 17.46
J225726.79+080540.6 16.99