TITLE:   GCN CIRCULAR
NUMBER:  32813
SUBJECT: GRB 221017A: CALET Gamma-Ray Burst Monitor detection
DATE:    22/10/21 15:48:27 GMT
FROM:    Yuta Kawakubo at Louisiana State U./CALET  <kawakubo1@lsu.edu>

M. L. Cherry (LSU), A. Yoshida, T. Sakamoto, S. Sugita (AGU), 
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
Y. Asaoka (ICRR), S. Torii, Y. Akaike, K. Kobayashi (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC),
S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena),
and the CALET collaboration:

The long GRB 221017A (MAXI/GSC detection: Nawa et al., GCN Circ. 32777;
IPN triangulation: Kozyrev et al., GCN Circ 32787)  was detected in the 
ground analysis of the CALET Gamma-ray Burst Monitor (CGBM) data around 
05:29:49 UTC on October 17, 2022 (referenced to GCN Circ 32787). 
The burst signal was seen by all CGBM detectors.

The burst light curve shows a multi-peaked structure that starts
at T-20.5 sec, peaks at T+176.6 sec and ends at T+670.4 sec.
The T90 and T50 durations measured by the SGM data are 191.9 +/- 44.4 sec
and 52.7 +/- 0.5 sec (40-1000 keV), respectively.

The ground-processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1350019714/

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