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GCN Circular 33786

GRB 230512A: GIT optical follow-up ZTF candidates
2023-05-12T22:45:11Z (a year ago)
Vishwajeet Swain at IIT Bombay <>
H. Kumar (IITB), V. Swain (IITB), A. Salgundi (IITB), V. Bhalerao (IITB), G.C. Anupama (IIA), S. Barway (IIA) and K. Angail (IAO) report on behalf of the GIT team:

We observed ZTF23aajfoed and ZTF23aajfilx detected by ZTF in localization region of the short GRB 230512A (Fermi GBM team, GCN 33778), with the 0.7m GROWTH-India Telescope (GIT). The observations started at 17:42:28 UT on 2023-05-12 for ZTF23aajfoed and at 17:08:25 for ZTF23aajfilx, roughly 11 hours after the Fermi GBM trigger. We obtained multiple 300s exposures in the g' and r' filters. We clearly detected the candidates at position reported by T. Ahumada et al., GCN 33784. The photometric results are follow as:

Target | mjd (mid) | Filter | Total Exposure (s) | Magnitude (AB) |


 ZTF23aajfoed | 60076.741640 | r' | 300 | 18.87 +/- 0.06 |
 ZTF23aajfoed | 60076.745515 | g' | 300 | 18.84 +/- 0.07 |
 ZTF23aajfilx | 60076.717906 | r' | 300 | 20.16 +/- 0.07 |
 ZTF23aajfilx | 60076.745515 | g' | 300 | 20.23 +/- 0.07 |


A comparison of GIT and ZTF observations suggests that both the targets are not evolving rapidly, indicating that they are unlikely to be GRB afterglows. 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 operations of the telescope. Telescope technical details are available at
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