[vsnet-grb-info 16065] GRB 150120B: Mondy optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17347
SUBJECT: GRB 150120B: Mondy optical observations
DATE:    15/01/23 19:00:55 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

E. Mazaeva (IKI), A. Volnova (IKI), E. Klunko (ISTP), I. Korobtsev 
(ISTP), M. Eselevich (ISTP), A. Pozanenko (IKI) report on behalf of 
larger GRB follow-up collaboration:

We observed the field of GRB 150120B  (D'Elia et al., GCN 17314) with 
AZT-33IK telescope of Sayan observatory (Mondy) Jan., 20  starting on 
(UT) 11:42:02. We obtained 65 images in R-filter of 120 s exposure. In 
two combined images within  enhanced Swift-XRT error circle (Goad
et al., GCN 17320) we clearly  detect optical  afterglow (Perley et al. 
GCN 17315, Guidorzi et al. GCN 17316). Photometry of the afterglow is 
following

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

2015-01-20 11:42:02   0.20149  R        30*120  21.25 0.22
2015-01-20 12:42:04   0.24348  R        30*120  21.43 0.25

Photometry is based on nearby USNO B1.0 (R2) stars:

USNO-B1.0_id R
0980-0031064 15.57
0980-0031070 14.16
0980-0031080 16.35
0980-0031095 15.41