TITLE:   GCN CIRCULAR
NUMBER:  42321
SUBJECT: GRB 251016A: CALET Gamma-Ray Burst Monitor detection
DATE:    25/10/17 07:26:43 GMT
FROM:    Yuta Kawakubo at Aoyama Gakuin University <kawakubo@phys.aoyama.ac.jp>

Y. Kawakubo , A. Yoshida, T. Sakamoto, S. Sugita (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 short GRB 251016A (SVOM detection: Basa et al., GCN Circ. 42308;
Fermi GBM Final Localization: Fermi GBM team, GCN Circ. 42309; Glowbug
gamma-ray detection: Woolf et al., GCN Circ. 42313) triggered the 
CALET Gamma-ray Burst Monitor (CGBM) at 14:59:19.37 UTC on 16 October 2025
(https://cgbm.calet.jp/cgbm_trigger/flight/1444661491/index.html).
The burst signal was seen by all CGBM detectors. 

The burst light curve shows a short pulse that starts
at T+0.32 sec, peaks at T+0.51 sec, and ends at T+0.69 sec.
The T90 and T50 durations measured by the SGM data are 0.29 +/- 0.05 sec
and 0.10+/- 0.03 sec (40-1000 keV), respectively.

The ground-processed light curve is available at

https://cgbm.calet.jp/cgbm_trigger/ground/1444661491/

The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.