GCN Circular 31496
Subject
GRB 220118A: GIT optical observations
Event
Date
2022-01-19T11:29:04Z (4 years ago)
From
Harsh Kumar at Indian Inst of Tech,Bombay <harshkosli13@gmail.com>
H. Kumar(IITB), J. Stanzin (IAO), V. Bhalerao(IITB), G. C. Anupama(IIA), S.
Barway(IIA) report on behalf of the GIT team:
We observed GRB 220118A detected by Fermi-GBM (GCN #31489) and Swift-BAT (N.
J. Klingler et al., GCN #31490) with 0.7m GROWTH-India Telescope (GIT). We
obtained multiple 300-sec exposures in the g', r', i' and z' filters. We
detect a faint (~ 3.5 sigma) afterglow in our stacked images. The obtained
upper magnitudes and upper limits follow as:
---------------------------------------------------------------------------------
JD (mid) | T_mid-T0(hrs) | Exposure (sec) | Filter | Mag(AB)/Lim_mag
(5-sigma)
---------------------------------------------------------------------------------
2459598.2802666 | 0.38 | 300 | r' | > 17.23
2459598.2839984 | 0.47 | 300 | i' | > 17.78
2459598.2877512 | 0.56 | 300 | g' | > 17.38
2459598.2915685 | 0.65 | 300 | z' | > 16.99
2459598.3202152 | 1.34 | 3000(stacked) | r' | > 19.84
---------------------------------------------------------------------------------
2459598.3568823 | 2.22 | 3000(stacked) | i' | 20.35 +/- 0.05
2459598.5042212 | 5.75 | 3000(stacked) | r' | 21.53 +/- 0.09
---------------------------------------------------------------------------------
The detected magnitudes and upper limits are in agreement with R. Hosokawa
et al., (GCN #31493). The magnitudes are calibrated against PanSTARRS DR1
(Chambers et al., 2016) 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/.