TITLE: GCN CIRCULAR NUMBER: 45345 SUBJECT: GRB 260804A: CALET Gamma-Ray Burst Monitor detection DATE: 26/08/10 13:46:23 GMT FROM: Yuta Kawakubo at Aoyama Gakuin University <kawakubo@phys.aoyama.ac.jp> T. Tamura (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), Y. Shimizu (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 260804A at 03:07:25.16 UTC on 4 August 2026 (trigger #1469848033; https://cgbm.calet.jp/cgbm_trigger/flight/1469848033/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 Fermi GBM (Fermi GBM team, GCN #45281; and Glowbug (Cheung et al., GCN #45288). The burst signal was seen by all CGBM detectors. The burst light curve shows a multi-peaked structure starting at T-18.7 s, peaking at T+2.4 s, and ending at T+3.3 s. The T90 and T50 durations measured with the SGM data are 20.3 +/- 1.0 s and 8.5 +/- 1.1 s in the 40-1000 keV band, respectively. The ground-processed light curve is available at: https://cgbm.calet.jp/cgbm_trigger/ground/1469848033/ 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/45345. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...