TITLE:   GCN CIRCULAR
NUMBER:  30506
SUBJECT: GRB 210723A: CALET Gamma-Ray Burst Monitor detection
DATE:    21/07/25 10:03:08 GMT
FROM:    Valentin Pal'shin at AGU  <val@phys.aoyama.ac.jp>

Y. Asaoka (ICRR),
A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
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 210723A (Swift detection: Sbarrato et al., GCN Circ. 30485,
Krimm and Barthelmy, GCN Circ. 30495; Fermi GBM Observation:
Lesage et al., GCN Circ. 30499;
https://gcn.gsfc.nasa.gov/other/210723A.gcn3) triggered the CALET Gamma-ray
Burst Monitor (CGBM) at 14:46:05.572 UTC on 23 July 2021
(http://cgbm.calet.jp/cgbm_trigger/flight/1311086521/index.html).
The burst signal was seen only by the SGM detector.

The burst light curve shows a single-pulse structure which starts
at T+0.9 sec, peaks at T+12.6 sec,and ends at T+22.0 sec.
The T90 and T50 durations measured by the SGM data are 17.2 +- 3.2 sec and
10.6 +- 3.2 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1311086521/

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