TITLE: GCN CIRCULAR NUMBER: 39040 SUBJECT: GRB 250126A: CALET Gamma-Ray Burst Monitor detection DATE: 25/01/26 15:05:47 GMT FROM: Yuta Kawakubo at Aoyama Gakuin University kawakubo@phys.aoyama.ac.jp

S. Sugita, A. Yoshida, T. Sakamoto, 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 250126A (Fermi GBM Final Real-time Localization: Fermi GBM team, GCN Circ. 39035; BALROG localization: Preis et al., GCN Circ 39036; MAXI/GSC detection: Okada et al., GCN Circ 39038) was detected in the ground analysis of the CALET Gamma-ray Burst Monitor (CGBM) data around 04:58:50.99 on 26 January 2025 (referenced to the Fermi-GBM Observation: GCN Circ. 39035). (https://cgbm.calet.jp/cgbm_trigger/flight/1421902612/index.html). The burst signal was seen by all CGBM detectors.

The burst light curve shows a multi-peaked structure that starts at T-0.3 sec, peaks at T+85.4 sec, and ends at T+100.1 sec. The T90 and T50 durations measured by the HXM2 data are 96.9 +/- 1.4 sec and 82.5 +/- 1.3 sec (7-100 keV), respectively.

The ground-processed light curve is available at

https://cgbm.calet.jp/cgbm_trigger/ground/1421902612/

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/39040. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...