TITLE: GCN CIRCULAR NUMBER: 45284 SUBJECT: GRB 260730B: CALET Gamma-Ray Burst Monitor detection DATE: 26/08/04 09:55:59 GMT FROM: Yuta Kawakubo at Aoyama Gakuin University <kawakubo@phys.aoyama.ac.jp> Y. Shimizu (Kanagawa U), A. Yoshida, T. Sakamoto, S. Sugita, Y. Kawakubo (AGU), K. Yamaoka (Nagoya U), S. Nakahira (JAXA), Y. Asaoka (ICRR), S. Torii, Y. Akaike, K. Kobayashi (Waseda U), T. Tamura (Kanagawa U), N. Cannady (GSFC), M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena), and the CALET collaboration: The CALET Gamma-ray Burst Monitor (CGBM) detected GRB 260730B at 13:13:50.13 UTC on 30 July 2026 (trigger #1469452426; https://cgbm.calet.jp/cgbm_trigger/flight/1469452426/index.html). No real-time CGBM GCN notice was distributed about this trigger because the real-time communication from the ISS was off (loss of signal). This event was also reported by NuSTAR (Waratkar et al., GCN #45262) and AstroSat CZTI (Goyal et al., GCN #45265). The burst signal was seen by all CGBM detectors. The burst light curve shows a multi-peaked structure starting at T-5.5 s, peaking at T+5.9 s, and ending at T+22.1 s. The T90 and T50 durations measured with the SGM data are 17.1 +/- 0.9 s and 6.1 +/- 0.9 s in the 40-1000 keV band, respectively. The ground-processed light curve is available at: https://cgbm.calet.jp/cgbm_trigger/ground/1469452426/ The CALET data used in this analysis were provided by the Waseda CALET Operation Center located at Waseda University. View this GCN Circular online at https://gcn.nasa.gov/circulars/45284. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...