GCN Circular 30908
Subject
GRB 210927A: GIT optical follow-up of ZTF21acdwctm.
Date
2021-10-01T03:59:51Z (3 years ago)
From
Harsh Kumar at Indian Inst of Tech,Bombay <harshkosli13@gmail.com>
H. Kumar(IITB), V. Bhalerao(IITB), J. Stanzin (IAO), G. C. Anupama(IIA), S.
Barway(IIA) report on behalf of the GIT team and the GROWTH Collaboration:
We observed ZTF21acdwctm reported by Shreya Anand et al. (GCN 30893), with 0.7m
GROWTH-India Telescope (GIT). We obtained multiple exposures in the
SDSS r' filter
spanning over 3 nights i.e. 2021-09-28, 2021-09-29, and 2021-09-30. We
clearly detected the afterglow in our stacked images on all 3 nights. The
photometric results follow as:
-------------------------------------------------------------------
JD (mid) | T_mid-T0(hrs) | Filter | Magnitude (AB) |
-------------------------------------------------------------------
2459486.16719 | 39.28 | r' | 21.32 +/- 0.07
2459487.12169 | 62.19 | r' | 21.59 +/- 0.09
2459488.13340 | 86.47 | r' | 21.92 +/- 0.08
-------------------------------------------------------------------
Based on GIT photometry we can conclude that the candidate is decaying with
a rate of ~0.3 mag/day. A further follow-up of this candidate is highly
encouraged.
The magnitudes are calibrated against PanSTARRS (Flewelling et al., 2018)
and not corrected for Galactic extinction.
The GROWTH India Telescope (GIT) is a 70-cm telescope with a 0.7-degree
field of view, set up by the Indian Institute of Astrophysics (IIA) and the
Indian Institute of Technology Bombay (IITB) with funding from DST-SERB and
IUSSTF. It is located at the Indian Astronomical Observatory (Hanle),
operated by IIA. We acknowledge funding by the IITB alumni batch of 1994,
which partially supports operations of the telescope. Telescope technical
details are available at https://sites.google.com/view/growthindia/.