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GCN Circular 35354

GRB 231215A: GROWTH-India optical follow-up
2023-12-15T15:35:12Z (7 months ago)
Vishwajeet Swain at IIT Bombay <>
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Y. Wagh, R. Kumar, V. Swain, A. Salgundi, V. Bhalerao (IIT Bombay), G. C. Anupama, S. Barway (IIA), K. Angail (IAO)

We observed the field of GRB 231215A detected by Swift (D'Avanzo et al., GCN Circ. 35343) with 0.7m GROWTH-India Telescope (GIT). We started the observation at 2023-12-15 13:48:10.312 UT, i.e., 4.01 hours after the Swift trigger. We obtained multiple images in the r' and g' filters. We clearly detected the afterglow near the uncertainty radius of Swift-XRT position reported by P.A. Evans et al., GCN Circ. 35345 and are consistent with the coordinate reported by M. Sasada at al., GCN Circ. 35351. The photometry results follow as:


| JD (mid) | t-t0 (hours) | Filter | Exposure (s) | Magnitude (AB) |


| 2460294.07510789 | 4.008 | r' | 380 | 19.65 +/- 0.08 | 
| 2460294.08452486 | 4.248 | g' | 380 | 20.44 +/- 0.11 | 


The results are consistent to the values reported by V.Lipunov et al., GCN Circ. 35347; N. Pankov et al., GCN Circ. 35349; M. Sasada et al., GCN Circ. 35351; J. An et al., GCN Circ. 35353. The magnitudes are calibrated against PanSTARRS DR1 (Chambers et al., 2016) and are not corrected for Galactic extinction.

The GROWTH India Telescope (GIT; Kumar et al. 2022) 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
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