[vsnet-grb-info 18538] GRB 161004A: SAO RAS optical upper limit

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19986
SUBJECT: GRB 161004A: SAO RAS optical upper limit
DATE:    16/10/04 23:02:45 GMT
FROM:    Moskvitin Alexander at SAO RAS  <mosk at sao.ru>

A. Moskvitin (SAO RAS), A. Volnova (IKI), and A. Pozanenko (IKI)
report on behalf of the larger GRB follow-up team.

We observed the field of GRB 161004A (Evans et al., GCN 19979)
with Zeiss-1000 - the 1-meter telescope of Special Astrophysical
Observatory of Russian Academy of Sciences. We obtain several
images with filter Rc starting on October, 4 (UT) 15:44:35.

In the refined XRT error circle (Beardmore et al., GCN 19983)
we do not detect the optical counterpart (Breeveld and Evans,
GCN 19984). Preliminary photometry of a combined image is following

Date       UT start   t-T0     Filter   Exp.   OT      UL
                   (mid, days)          (s)
2016-10-04 15:44:35   0.1396    Rc      12*300 n/d    22.4

Photometry is based on nearby SDSS-DR9 stars reported
by Mazaeva et al. (GCN 19980).