GCN Circular 16780
Subject
GRB 140818B: TShAO optical upper limit
Date
2014-09-05T06:16:20Z (10 years ago)
From
Alexei Pozanenko at IKI <alex@grb.rssi.ru>
A. Pozanenko (IKI), I. Rewa, W. Mundrzyjewski, A. Kusakin (Fesenkov Astrophysical Institute), A. Volnova (IKI), report on behalf of larger GRB follow-up collaboration:
We observed the field of the Swift GRB 140818B (Vargas et al., GCN 16709)with Zeiss-1000 (East) telescope of Tien Shan Astronomical Observatory starting on Aug. 19, (UT) 17:05. We took several images in R-filter. Within enhanced XRT error circle (Beardmore et al., GCN 16712) we do not detect the afterlow (Aceituno et al., GCN 16711; Knust et al., GCN 16713). The source mentioned by Knust et al. (GCN 16713) is clearly visible in a stacked image in coordinates (J2000) 18:04:32.76 -01:23:08.9 (uncertainty is 0.2 arcsec in both coordinates) and has brightness of R=22.1+/-0.1.
Details of a photometry of the stacked image are following
Date UT start t-T0,d Exp,s Filter Up_Lim (3 sigma)
(mid)
2014-08-19 16:11:12 0.9317 20*600 R 22.9
The photometry is based on nearby USNO-B1.0 stars, R2 magnitudes.