TITLE: GCN CIRCULAR NUMBER: 38020 SUBJECT: GRB 241030B: Montarrenti Observatory optical upper limit DATE: 24/10/31 23:48:16 GMT FROM: Simone Leonini at Montarrenti Observatory (Siena, Italy) <s.leonini@iol.it> S. Leonini, M. Conti, P. Rosi, L.M. Tinjaca Ramirez (Montarrenti Observatory, Siena, Italy, part of UAI/SSV-GRB section), M.G. Dainotti (National Astronomical Observatory of Japan), Y. Niino (Tokyo University, Institute of Astronomy), K. Kalinowski (Aarhus University, Department of Physics and Astronomy) and B. De Simone (Universita' degli Studi Di Salerno) report: We performed follow-up observations of the field of GRB 241030B with the automated and remoted 0.53m Ritchey-Chretien telescope at Montarrenti Observatory (Siena, Italy, IAU code C88). Observations were started at 2024-10-30 21:55:28 UT, 3.33 hours after burst (Fermi-GBM team, GCN 37980; Swift trigger 1263840, GCN 37981 Klingler et al.; SVOM/ECLAIRs, GCN 37984 Zhao et al.) stacking 140x40s Rc-band CCD images. In our preliminary analysis, we have not found any optical transient candidate within the error-box (2.4 arcmin.) of the Neil Gehrels Swift Observatory enhanced position (RA 03h 23m 10.19s, Dec. +34d 26m 49.2s - J2000) down to the following 3-sigma optical upper limits: MJD Exp. Filter UL (3-sigma) 60614.4476 140x40s Rc > 20.91 Magnitude was calibrated with the nearby PanSTARRS stars converted using Lupton (2005) equations. No correction for galactic dust extinction was applied. Our observations are consistent with other fading detection and upper limits already reported (Fu et al., GCN 37985; Odeh et al., GCN 37986; Moskvitin et al., GCN 37987; Klotz et al., GCN 37989; 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; Strausbaugh et. al., GCN 38012; Swain et al., GCN 38013). View this GCN Circular online at https://gcn.nasa.gov/circulars/38020. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...