GCN Circular 42402
Subject
GRB 251023B: CALET Gamma-Ray Burst Monitor detection
Event
Date
2025-10-23T16:16:02Z (2 days ago)
From
Yuta Kawakubo at Aoyama Gakuin University <kawakubo@phys.aoyama.ac.jp>
Via
Web form
S. Nakahira (JAXA), A. Yoshida, T. Sakamoto, S. Sugita, Y. Kawakubo (AGU),
K. Yamaoka (Nagoya U), 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 251023B (MAXI/GSC Detection: Kang et al., GCN Circ
42392) was detected in the ground analysis of the CALET Gamma-ray
Burst Monitor (CGBM) data around 08:49:03 on 23 October 2025 (referenced
to the MAXI detection: GCN Circ. 42392).
(https://cgbm.calet.jp/cgbm_trigger/flight/1445244062/index.html).
The burst signal was seen by all CGBM detectors.
The burst light curve shows a multi-peaked structure that starts
at T-31.7 sec and ends at T+8.2 sec.
The T90 and T50 durations measured by the HXM2 data are 34.9 +/- 4.2 sec
and 16.7 +/- 2.2 sec (7-100 keV), respectively.
The ground-processed light curve is available at
https://cgbm.calet.jp/cgbm_trigger/ground/1445244062/
The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.