A. Volnova (IKI), A. Pozanenko (IKI), A. Mokhnatkin (KIAM), R.
Inasaridze (AbAO), E. Mazaeva (IKI), V. Agletdinov (KIAM), V. Ayvazian
(AbAO), O. Kvaratskhelia (AbAO), G. Inasaridze (AbAO), I. Molotov (KIAM)
report on behalf of larger GRB follow-up collaboration:
We observed the field of the Swift GRB 170711A (D'Elia et al. GCN 21321)
with K-800 (0.8m) telescope of ISON/Terskol observatory starting on July,
12 (UT) 00:00:39 and AS-32 telescope of AbAO starting on July, 11 (UT)
23:58:46, i.e. about 1.6 hours after GRB trigger. We obtained
several unfiltered images. We do not detect any source in stacked images
within the enhanced XRT position (Beardmore et al. GCN 21323).
Preliminary photometry of the field is following
Date UT start t-T0 Filter Exp. OT Err. UL
(mid, days) (s)
2017-07-11 23:58:46 0.07894 CR 11*60 n/d n/d 17.0 AS-32
2017-07-12 00:00:39 0.07658 CR 45*25 n/d n/d 19.1 K-800
Photometry is based on nearby stars of USNO-B1.0
We detect the object in coordinates (J2000) 03 03 11.46 +47 50 56.1 (+/-
0.5 arcsec) which is 7.7 arcsec apart from a center of the enhanced XRT
position. The object is clearly detected in the stacked image of K-800 and
marginally seen at the same position with AS-32 stacked image. The
brightness of the object is 18.56 +/- 0.25 based on the reference stars
listed above. The object is absent in the USNO-B1.0. At present, it is not
clear whether this object has any relation to the GRB 170711A.