TITLE: GCN CIRCULAR NUMBER: 44989 SUBJECT: GRB 260617A: CALET Gamma-Ray Burst Monitor detection DATE: 26/06/19 08:20:00 GMT FROM: Yuta Kawakubo at Aoyama Gakuin University <kawakubo@phys.aoyama.ac.jp> S. Torii (Waseda U), A. Yoshida, T. Sakamoto, S. Sugita, Y. Kawakubo (AGU), K. Yamaoka (Nagoya U), S. Nakahira (JAXA), Y. Asaoka (ICRR), Y. Akaike, K. Kobayashi (Waseda U), Y. Shimizu, 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 260617A at 21:36:43.92 UTC on 17 June 2026 (trigger #1465767277; https://cgbm.calet.jp/cgbm_trigger/flight/1465767277/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 (The Fermi GBM team et al., GCN #44969; Godwin et al., GCN #44972), Konus-Wind and Mars-Odyssey (IPN triangulation: Kozyrev et al., GCN #44982). The burst signal was seen by HXM1 and SGM. The burst light curve shows a short pulse from T-0.25 s to T-0.15 s. The T90 and T50 durations measured with the SGM data are 0.09 +/- 0.02 s and 0.05 +/- 0.01 s in the 40-1000 keV band, respectively. The ground-processed light curve is available at: https://cgbm.calet.jp/cgbm_trigger/ground/1465767277/ 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/44989. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...