GCN Circular 33797
Subject
GRB 230512A: GIT non detection of afterglow candidate
Date
2023-05-14T16:41:15Z (a year ago)
From
Vishwajeet Swain at IIT Bombay <vishwajeet.s@iitb.ac.in>
V. Swain (IITB), H. Kumar (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 the region of short GRB 230512A (Fermi GBM team, GCN 33778 and D. J. Maheso et al., GCN 33780), with the 0.7m GROWTH-India Telescope (GIT) covering the position of afterglow detected by S. Belkin et al., GCN 33796, . The observations started at 20:41:30 UT on 2023-05-12, 14.22 hours after the Fermi GBM trigger and 1.4 hours after the commencement of Kitab RC-36 observations (Belkin et al., GCN #33796). We obtained two exposures of 400s each in the r' band, coincidentally overlapping with the end of their first epoch. We later imaged the field in the g' band as well, with 2x400s exposures. We search individual images and the stacked image for an afterglow, but find no afterglow candidates. In particular, we do not detect the optical afterglow emission reported by S. Belkin et al., GCN 33796, despite our images having sufficient depth. Our upper limits are as follows:
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JD (mid) | T_mid-T0(hrs) |T_mid - T(Kitab)|Filter | Total Exposure (s) | Lim_mag (5-sigma) |
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2460077.364615665 | 14.28 | 1.46 | r' | 2 X 400 (stacked) | >20.39 |
2460077.43835897 | 15.88 | 3.05 | g' | 2 x 400 (stacked) | >21.08 |
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We note that there is no known minor planet at this location in MPC. 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 https://sites.google.com/view/growthindia/.