GCN Circular 21623
Subject
LIGO/Virgo G298048: Kanata/HONIR NIR photometry of the possible counterpart of G298048
Date
2017-08-20T16:37:38Z (7 years ago)
From
Koji S. Kawabata at JGEM <kawabtkj@hiroshima-u.ac.jp>
T. Nakaoka, K. S. Kawabata, M. Kawabata, H. Nagashima, and
Y. Utsumi (Hiroshima University) on behalf of J-GEM collaboration.
We performed H-band imaging of the possible counterpart of G298048,
SSS17a in NGC 4993 identified by Coulter et al. (LVC GCN 21529),
with HONIR on the 1.5-m Kanata telescope at Higashi-Hiroshima
Observatory, Japan.
Because of low-elevation observation (height~10 deg) during bright
twilight, the foreground sky level was still high and SSS17a was
considerably faint (~3 sigma) in our stacked image. We performed
a forced aperture photometry and estimated a preliminary magnitude
in AB system of
H = 16.7 (2017 August 20.424-429 UT; MJD 57985.424-429)
The magnitude is calibrated against 2MASS field stars. Further
analysis is in progress.