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GCN Circular 35041

GRB 231115A: GROWTH-India discovery of a potential optical counterpart
2023-11-15T18:30:14Z (6 months ago)
Varun Bhalerao at IIT Bombay <>
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R. Kumar, A. Salgundi, V. Swain, Y. Wagh, V. Bhalerao (IIT Bombay), G. C. Anupama, S. Barway (IIA), R. Norboo (IAO), T. Ahumada, V. Karambelkar, M. M. Kasliwal (Caltech) report on behalf of a larger collaboration

We observed the field of GRB 231115A (Fermi GBM Team, GCN 35035) with 0.7m GROWTH India telescope. We started observations at 2023-11-15 16:47:58.140 UT, 1.19 hours after the fermi trigger (as soon as the source became visible). We obtained multiple 300s exposures in multiple filters. We have multiple detections of a transient AT 2023xvj at RA = 09:56:00.2, Dec = 69:40:29.2, with r' = 19.2. Owing to the dense background, current total astrometric uncertainty is about 0.6". The source is 0.3' from the reported Integral position, consistent with their 2' uncertainty. The magnitudes are calibrated against PanSTARRS DR1 (Chambers et al., 2016) and not corrected for Galactic extinction.

At this stage, we cannot rule out that this might be Nova or some other transient in M82. Further imaging and analysis is under way. We strongly encourage follow-up observations.

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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