TITLE:   GCN CIRCULAR
NUMBER:  32185
SUBJECT: GRB 220609B: CALET Gamma-Ray Burst Monitor detection
DATE:    22/06/10 03:31:48 GMT
FROM:    Yuta Kawakubo at Louisiana State U./CALET  <kawakubo1@lsu.edu>

Y. Asaoka (ICRR), A. Yoshida, T. Sakamoto, 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 220609B triggered the CALET Gamma-ray
Burst Monitor (CGBM) at 12:21:07.969 UTC on 9 June 2022
(http://cgbm.calet.jp/cgbm_trigger/flight/1338812272/index.html).
The burst signal was seen by all CGBM detectors.

The burst light curve shows a multi-peaked structure which starts
at T-6.4 sec, peaks at T+7.9 sec, and ends at T+14.1 sec.
The T90 and T50 durations measured by the SGM data are 9.9 +/- 1.0 sec
and 3.5 +/- 0.2 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1338812272/

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