GCN Circular 21189
Subject
GRB 170531B: ISON/Terskol optical observations
Date
2017-06-02T15:22:42Z (7 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Mazaeva (IKI), A. Mokhnatkin (KIAM), A. Pozanenko (IKI), A.
Volnova (IKI), I. Molotov (KIAM) report on behalf of larger GRB
follow-up collaboration:
We observed the field of GRB 170531B (Evans et al.,GCN 21171) with
K-800 (0.8m) telescope of ISON/Terskol observatory starting on May,
31 (UT) 22:21:31. We obtained several unfiltered images of 40 s
exposure. The optical afterglow (Lipunov et al., GCN 21173 Pozanenko et
al. GCN 21174) is clearly visible in combined images. Preliminary
photometry of the afterglow is following
Date UT start t-T0 Filter Exp. OT Err. UL
(mid, days) (s)
2017-05-31 22:21:31 0.01810 CR 18*40 18.90 0.10 21.0
2017-05-31 22:35:41 0.02949 CR 21*40 19.10 0.10 21.0
Photometry is based on nearby USNO-B1.0 stars
USNO-B.1_id R2
0736-0718845 16.77
0735-0729626 17.35
0735-0729622 16.96
0735-0729439 16.59
0735-0729327 17.22