TITLE: GCN CIRCULAR NUMBER: 42156 SUBJECT: GRB 251007A: CALET Gamma-Ray Burst Monitor detection DATE: 25/10/08 05:38:59 GMT FROM: Yuta Kawakubo at Aoyama Gakuin University <kawakubo@phys.aoyama.ac.jp> 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, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena), and the CALET collaboration: The long GRB 251007A (Swift detection: Ambrosi et al., GCN Circ. 42146; Glowbug gamma-ray detection: Cheung et al., GCN Circ. 42151) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 19:37:48.18 UTC on 7 October 2025 (https://cgbm.calet.jp/cgbm_trigger/flight/1443900615/index.html). The burst signal was seen by all CGBM detectors. The burst light curve shows a multi-peaked structure that starts at T+3.0 sec, peaks at T+6.3 sec, and ends at T+21.9 sec. The T90 and T50 durations measured by the SGM data are 15.7 +/- 0.3 sec and 9.2 +/- 0.3 sec (40-1000 keV), respectively. The ground-processed light curve is available at https://cgbm.calet.jp/cgbm_trigger/ground/1443900615/ The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at Waseda University. View this GCN Circular online at https://gcn.nasa.gov/circulars/42156. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...