GCN Circular 45347
Subject
GRB 260808A: CALET Gamma-Ray Burst Monitor detection
Event
Date
2026-08-10T13:51:56Z (11 hours ago)
From
Yuta Kawakubo at Aoyama Gakuin University <kawakubo@phys.aoyama.ac.jp>
Via
Web form
M. L. Cherry (LSU), 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), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena),
and the CALET collaboration:
The CALET Gamma-ray Burst Monitor (CGBM) detected GRB 260808A
at 02:51:52.41 UTC on 8 August 2026 (trigger #1470192693;
https://cgbm.calet.jp/cgbm_trigger/flight/1470192693/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 (Fermi GBM Team, GCN #45313;
Preis and Greiner, GCN #45315) and NuSTAR (Waratkar et al., GCN #45327).
The burst signal was seen by all CGBM detectors.
The burst light curve shows a multi-peaked structure starting
at T-10.6 s and ending at T+4.4 s.
The T90 and T50 durations measured with the SGM data are 13.4 +/- 0.9 s
and 7.1 +/- 0.6 s in the 40-1000 keV band, respectively.
The ground-processed light curve is available at:
https://cgbm.calet.jp/cgbm_trigger/ground/1470192693/
The CALET data used in this analysis were provided by
the Waseda CALET Operation Center located at Waseda University.