GCN Circular 22809
Subject
GRB 180618A: TSHAO optical upper limit
Date
2018-06-20T17:57:39Z (6 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Mazaeva (IKI), A. Kusakin (FAPHI), A. Pozanenko (IKI), I. Reva
(FAPHI), A. Volnova (IKI), M. Krugov (FAPHI) report on behalf of
larger GRB follow-up collaboration:
We observed the field of GRB GRB 180618A (LaPorte et al., GCN 22790)
with Zeiss-1000 1-m telescope of Tien Shan Astronomical Observatory
starting on June 18 (UT) 15:39:19. We obtained several images in
R-filter. The optical afterglow (LaPorte et al., GCN 22790; Guidorzi et
al., GCN 22792; Tyurina et al., GCN 22797) is not detected in a stacked
image. Preliminary photometry of the field is following.
Date UT start t-T0 Filter Exp. OT Err. UL
(mid, days) (s)
2018-06-18 15:39:19 0.65209 R 36*120 n/d n/d 22.2
The photometry is based on several nearby SDSS-DR10 stars.
Ref.stars
SDSS_id R(Lupton)
J112037.79+735136.8 17.37
J111905.28+734733.2 17.54
J111907.19+734657.8 17.04