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GCN Circular 33182

Subject
GRB 230116D: GIT optical follow-up
Date
2023-01-17T05:03:49Z (a year ago)
From
Varun Bhalerao at Indian Inst of Tech <varunb@iitb.ac.in>
V. Swain (IITB), H. Kumar (IITB), K. Angail (IAO), V. Bhalerao (IITB), G. C. Anupama(IIA), S. Barway (IIA) report on behalf of the GIT team:

[The previous GCN was garbled up, re-posting]

We observed GRB 230116D detected by Swift-BAT (Sonbas et al., GCN 33176Not found
 
 
) and optical afterglow discovered by Z.P. Zhu et al.(GCN 33177Not found
 
 
), with 0.7m GROWTH-India Telescope (GIT). We started the observation at 21:39:00 UT on 2023-01-16, i.e., 34.28 min after the Swift/BAT trigger and took multiple exposures in the g���, r' and i��� filters. We clearly detected the afterglow in our stacked image at R.A.= 06:34:28.13, DEC.=+49:52:20.6, within the 2.3 arcsec radius circle (J.P. Osborne et al., GCN 33180Not found
 
 
). The photometric results follow as:
-------------------------------------------------------------------
 JD (mid) | T_mid-T0(hrs) | Exposure (sec) | Filter | Magnitude (AB) |
-------------------------------------------------------------------
 2459961.40208328 | 0.57 | 1 x 20           | r' | >17.63 |
 2459961.41763334 | 0.94 | 8 x 300 (stacked) | g��� | 21.04 +/- 0.07 |
 2459961.44794164 | 1.67 | 8 x 300 (stacked) | r��� | 19.99 +/- 0.05 |
 2459961.47255148 | 2.26 | 5 x 300 (stacked) | i��� | >19.84 |
-------------------------------------------------------------------

The results are consistent with S. Nazarov et al.(GCN #33178) and A. S. Moskvitin et al.(GCN #33179).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) 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 telescope���s operations. Telescope technical details are available at https://sites.google.com/view/growthindia/.