TITLE:   GCN CIRCULAR
NUMBER:  34700
SUBJECT: GRB 230913A: CALET Gamma-Ray Burst Monitor detection
DATE:    23/09/15 03:21:21 GMT
FROM:    Yuta Kawakubo at Louisiana State University <kawakubo1@lsu.edu>

M. L. Cherry (LSU), 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),
S. Ricciarini (U of Florence),
P. S. Marrocchesi (U of Siena),
and the CALET collaboration:

The long GRB 230913A (Fermi GBM Final Real-time Localization: 
Fermi GBM team, GCN Circ. 34680; Swift/BAT-GUANO arcminute 
localization, Ronchini et al., GCN Circ. 34683; Fermi GBM Observation:
Dalessi et al., GCN Circ. 34689; Glowbug gamma-ray detection: Kerr et al.,
GCN Circ. 34696) triggered the CALET Gamma-ray Burst Monitor (CGBM) 
at 07:56:11.95 UTC on 13 September 2023
(http://cgbm.calet.jp/cgbm_trigger/flight/1378626813/index.html).
The burst signal was seen by all CGBM detectors.

The burst light curve shows a single pulse that starts
at T+0.9 sec, peaks at T+1.5 sec, and ends at T+4.4 sec.
The T90 and T50 durations measured by the SGM data are 3.1 +/- 0.3 sec
and 1.9 +/- 0.4 sec (40-1000 keV), respectively.

The ground-processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1378626813/

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