TITLE: GCN CIRCULAR NUMBER: 38013 SUBJECT: GRB 241030B : GIT optical upper limits DATE: 24/10/31 14:28:02 GMT FROM: V. Swain at IIT Bombay <vishwajeet.s@iitb.ac.in> V. Swain, A.P. Saikia, T. Mohan, R. Kumar, V. Bhalerao (IITB), G.C. Anupama, S. Barway (IIA) and K. Angail (IAO) report on behalf of the GIT team: We observed the field of GRB 241030B (Fermi GBM Team, GCN 37980, Klingler et al. GCN 37981) with 0.7m GROWTH-India Telescope (GIT) in g', r', and i' filters. We started the observation at 2024-10-30 18:42:39 UT, i.e., 8.3 mins after the Fermi GBM trigger. We took multiple exposures and obtained upper limits at the position reported by Fu et. al., (GCN 37985). The photometry results follow as: ------------------------------------------------------------------------------ | JD (mid) | t-t0 (mins) | Filter | Exposure (s) | Upper limit (AB) | | ----------------- | ----------- |------- | ------------ | -------------- | | 2460614.279618055 | 8.32 | r' | 20 | 18.9 | | 2460614.281053241 | 10.38 | g' | 20 | 18.7 | | 2460614.282048611 | 11.82 | i' | 30 | 18.0 | | 2460614.434398148 | 231.2 | g' | 440 | 21.2 | | 2460614.439745370 | 238.9 | r' | 440 | 21.3 | | 2460614.445185185 | 246.7 | i' | 400 | 20.2 | ------------------------------------------------------------------------------ Our results are consistent with Fu et al.; (GCN 37985), Odeh et al.; (GCN 37986), Moskvitin et al.; (GCN 37987), Brivio et al.; (GCN 37991), Moskvitin et al.; (GCN 37995), Watson et al.; (GCN 37998), Qiu et al.; (GCN 37999), Hagio et al.; (GCN 38001), Tanvir et. al.; (GCN 38004), Breeveld et. al.; (GCN 38008), Strausbaugh et. al.; (GCN 38012). The measurement is 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 operations of the telescope. Telescope technical details are available at https://sites.google.com/view/growthindia/. View this GCN Circular online at https://gcn.nasa.gov/circulars/38013. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...