TITLE:   GCN CIRCULAR
NUMBER:  18991
SUBJECT: GRB 160131A: Mondy optcial observations
DATE:    16/02/05 15:15:24 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

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

We observed the Swift GRB 160131A (Page et al., GCN 18951) with AZT-33IK 
telescope of Sayan observatory (Mondy)  starting on Feb.04 (UT) 
11:42:43. We detect optical afterglow (Page et al., GCN 18951; Yurkov et 
al., GCN 18952; Guidorzi et al., GCN 18953; Xin et al., GCN 18954; Xin 
et al., GCN 18955; Watson et al., GCN 18956) in a combined image. 
Preliminary photometry is following


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


2016-02-04  11:42:43  4.16058  R       29*120  21.70  0.23

USNO-B.1_id     R2

0829-0078147    14.56
0829-0078222    18.96
0829-0078226    18.69
0829-0078129    17.62