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GCN Circular 32841

Subject
GRB 221024A: GIT confirmation of the optical afterglow
Date
2022-10-25T09:04:49Z (2 years ago)
From
Harsh Kumar at Indian Inst of Tech,Bombay <harshkosli13@gmail.com>
V. Swain (IITB), H. Kumar (IITB), A. Kaysang (IAO), V. Bhalerao (IITB), G.
C. Anupama(IIA) and S. Barway (IIA) report on behalf of the GIT team:

We observed GRB 221024A detected by Swift-BAT (R. Brivio et al., GCN
#32827) with 0.7m GROWTH-India Telescope (GIT). We obtained multiple 300s
exposures in the r' filter and clearly detected the afterglow in our image
at R.A.= 11:18:57.78  DEC = +33:02:30.64. The photometric results follow as:

--------------------------------------------------------------------

JD (Start) | T_Start-T0(hrs) | Filter | Magnitude (AB) |

--------------------------------------------------------------------

2459877.42179 |  9.12 | r' | 18.36 +/- 0.05 |

2459877.45883 | 10.00 | r' | 18.50 +/- 0.1 |

--------------------------------------------------------------------

GIT photometry and results from Jan Strobl et al. (GCN #32838) conclude
that the source is fading and is an afterglow of GRB 221024A. The
magnitudes are calibrated against PanSTARRS DR1 (Chambers et al., 2016) and
not corrected for Galactic extinction.

The GROWTH India Telescope (GIT; Kumar et al. 2022
<https://iopscience.iop.org/article/10.3847/1538-3881/ac7bea>) 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 the operations
of the telescope. Telescope technical details are available at
https://sites.google.com/view/growthindia/.
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