[vsnet-grb-info 17532] GRB 160131A: Khureltogot optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18962
SUBJECT: GRB 160131A: Khureltogot optical observations
DATE:    16/01/31 20:22:21 GMT
FROM:    Alexei Pozanenko at IKI  <alex at grb.rssi.ru>

E. Mazaeva (IKI), S. Schmalz (AIP),  N. Tungalag (Research Center of Astronomy and Geophysics MAS), A. Volnova (IKI), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:

We observed the field of Swift GRB 160131A (Page et al., GCN Page) with ORI-40 telescope of Khureltogot observatory  on Jan., 31 from(UT)  11:14 up to (UT) 16:34. We obtained several unfilteed images.
We clearly 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). Preliminary photometry of the afterglow in the first images is following


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

                                                                             
2016-01-31  11:14:41 0.12106     20   16.43      0.10
2016-01-31  11:27:26 0.13015     60   16.49      0.04
2016-01-31  11:28:30 0.13089     60   16.51      0.04
2016-01-31  11:29:35 0.13164     60   16.50      0.04
2016-01-31  11:30:39 0.13238     60   16.52      0.05
2016-01-31  11:31:43 0.13388     60   16.61      0.05
2016-01-31  11:33:52 0.13462     60   16.46      0.04
2016-01-31  11:34:57 0.13537     60   16.53      0.05
2016-01-31  11:36:01 0.13611     60   16.58      0.05
2016-01-31  11:37:06 0.13686     60   16.62      0.05
2016-01-31  11:38:10 0.13760     60   16.56      0.04
2016-01-31  11:39:14 0.13834     60   16.58      0.04
2016-01-31  11:40:18 0.13909     60   16.57      0.04

Photometry is based on nearby USNO B1.0 stars, R2 magnitude.