[vsnet-grb-info 20235] GRB 180111A: AbAO optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22331
SUBJECT: GRB 180111A: AbAO optical observations
DATE:    18/01/13 19:36:34 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

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

We observed the field of the Swift  GRB 180111A (Lien et al., GCN 22318) 
with AS-32 (0.7m) telescope of Abastumani Observatory starting on Jan., 11 
(UT)  23:53:51. We obtained several unfiltered images of the field.   Within 
enhanced XRT error circle  (Evans et al., GCN   22319) we detected the 
afterglow (Lien et al., GCN  22318; Xin et al., 22320; GCN  Butler  et al., 
GCN  22323; Gropp  et al., GCN   22327).
Preliminary photometry of the afterglow is following

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

2018-01-11 23:53:51   0.3213  CR     62*60  20.7  0.2  22.0

Photometry is based on nearby USNO-B1.0 stars (R2 magnitudes)
USNO-B.1_id    R2
1382-0239231 15.78
1383-0226386 16.52
1383-0226440 15.90