[vsnet-grb-info 18532] GRB 161004A: TSHAO optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19980
SUBJECT: GRB 161004A: TSHAO optical observations
DATE:    16/10/04 17:44:41 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

E. Mazaeva (IKI), I. Reva (Fesenkov Astrophysical Institute), A. Kusakin 
(Fesenkov Astrophysical Institute),  A. Volnova (IKI), A. Pozanenko 
(IKI) report on behalf of larger GRB follow-up collaboration:

We observed the field of GRB 161004A  (Evans  et al., GCN 19979)  with 
Zeiss-1000 (East) 1-m telescope of Tien Shan Astronomical Observatory. 
We obtained several images in R filter starting on Oct. 04 (UT) 
13:36:52.  In the XRT error circle we do not detect any new object. Wa 
do not detect also candidate afterglow (Evans  et al., GCN 19979). 
Preliminary photometry of a combined image is following

Date       UT start   t-T0   Filter   Exp.  OT     Err.  UL
                       (mid, days)     (s)
2016-10-04 13:36:52 0.04321  R       15*180 n/d    n/d   21.9

Photometry is based on nearby SDSS-DR9 stars (Lupton transformations):
SDSS-DR9_id         R(Lupton)
J173243.09-005731.3 17.04
J173250.91-005842.7 16.77
J173251.94-005803.2 15.75
J173253.88-005801.6 15.62
J173253.02-005938.3 16.02
J173232.00-005640.3 16.34
J173227.11-005646.8 16.41
J173227.04-005816.8 16.51
J173227.48-005856.9 16.62
J173236.27-010018.1 16.96
J173241.54-005823.1 16.26

A finding chart can be found at 
http://grb.rssi.ru/GRB161004A/GRB161004A_TSHAO_161004_XRT_UVOT.png