TITLE:   GCN CIRCULAR
NUMBER:  34909
SUBJECT: GRB 231028A: CALET Gamma-Ray Burst Monitor detection
DATE:    23/10/30 04:07:26 GMT
FROM:    Yuta Kawakubo at Louisiana State University <kawakubo1@lsu.edu>

A. Yoshida, T. Sakamoto, S. Sugita (AGU), Y. Kawakubo (LSU),
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 long GRB 231028A (Fermi GBM Final Real-time Localization: 
Fermi GBM team, GCN Circ. 34893; Swift detection: Williams et al.,
GCN Circ. 34894; Fermi GBM Detection: Veres et al., GCN Circ. 34899; 
Glowbug gamma-ray detection: Kerr et al., GCN Circ. 34900; 
AstroSat CZTI detection: Navaneeth et al.,  GCN Circ. 34901) 
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 04:09:04.43
UTC on 28 October 2023
(http://cgbm.calet.jp/cgbm_trigger/flight/1382501309/index.html).
The burst signal was seen by all CGBM detectors.

The burst light curve shows a multi-peaked structure that starts
at T+0.25 sec, peaks at T+6.5 sec, and ends at T+47.5 sec.
The T90 and T50 durations measured by the SGM data are 36.1 +/- 1.2 sec
and 6.9 +/- 1.1 sec (40-1000 keV), respectively.

The ground-processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1382501309/

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