GCN Circular 42027
Subject
GRB 250926A: CALET Gamma-Ray Burst Monitor detection
Event
Date
2025-09-29T15:19:54Z (3 days ago)
From
Yuta Kawakubo at Aoyama Gakuin University <kawakubo@phys.aoyama.ac.jp>
Via
Web form
S. Ricciarini (U of Florence), 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), P. S. Marrocchesi (U of Siena),
and the CALET collaboration:
The GRB 250926A (Fermi GBM Final Real-time Localization:
Fermi GBM team, GCN Circ. 41993; AstroSat CZTI detection: Goyal
et al., GCN Circ. 42008; Insight-HXMT detection: Wang et al., GCN Circ.
42013; triangulation location with Insight-HXMT/HE and Fermi/GBM: Zhang
et al., GCN Circ. 42019) triggered the CALET Gamma-ray Burst Monitor (CGBM)
at 00:21:23.82 UTC on 26 September 2025
(https://cgbm.calet.jp/cgbm_trigger/flight/1442880852/index.html).
The burst signal was seen by only the SGM detector.
The burst light curve shows a single pulse that starts
at T+0.75 sec, peaks at T+1.08 sec, and ends at T+1.35 sec.
The T90 and T50 durations measured by the SGM data are 0.55 +/- 0.11 sec
and 0.25 +/- 0.10 sec (40-1000 keV), respectively.
The ground-processed light curve is available at
https://cgbm.calet.jp/cgbm_trigger/ground/1442880852/
The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.