GCN Circular 31738
Subject
GRB 220310A: GIT confirmation of optical afterglow.
Date
2022-03-11T10:23:08Z (2 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 220310A detected by MAXI/GSC H. Negoro et al., (GCN #31725)
and optical afterglow discovered by V. Lipunov (GCN #31732), with 0.7m
GROWTH-India Telescope (GIT). We obtained multiple 300-sec exposures in the
g',r' and i' filters. We clearly detected the afterglow in our stacked
image. The photometric results follow as:
-------------------------------------------------------------------
JD (mid) | T_mid-T0(days) | Filter | Magnitude (AB) |
-------------------------------------------------------------------
2459649.085963 | 0.566 | g' | 19.86 +/- 0.03
2459649.093405 | 0.574 | r' | 19.45 +/- 0.04
2459649.100833 | 0.581 | i' | 19.11 +/- 0.04
2459649.327412 | 0.810 | g' | 20.66 +/- 0.08
2459649.334752 | 0.815 | r' | 20.21 +/- 0.07
2459649.342128 | 0.823 | i' | 19.70 +/- 0.09
-------------------------------------------------------------------
On the basis of fading seen in our observations, we confirm the MASTER OT
J111302.33+231508.0 (GCN #31732) as an afterglow of GRB 220310A. Further,
using our r'-band data, we estimated the index of power-law decay index =
1.99 +/- 0.17. 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/.