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TITLE:   GCN CIRCULAR
NUMBER:  33145
SUBJECT: GRB 221230A: CALET Gamma-Ray Burst Monitor detection
DATE:    23/01/04 04:28:35 GMT
FROM:    Yuta Kawakubo at Louisiana State U./CALET  <kawakubo1@lsu.edu>

K. Yamaoka (Nagoya U), A. Yoshida, T. Sakamoto,
S. Sugita (AGU), Y. Kawakubo (LSU), 
S. Nakahira (RIKEN), 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 221230A (Wind-KONUS Notice at 03:34:17.508 on 30 December) 
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 03:34:17.34 UTC 
on December 30, 2022
(http://cgbm.calet.jp/cgbm_trigger/flight/1356406433/index.html).
The burst signal was seen by all CGBM detectors.

The burst light curve shows a multi-peaked structure that starts
at T+0.6 sec, and peaks at T+16.0 sec and ends at T+21.7 sec.
The T90 and T50 durations measured by the SGM data are 18.6 +/- 0.9 sec
and 13.5 +/- 0.5 sec (40-1000 keV), respectively.

The ground-processed light curve is available at

 http://cgbm.calet.jp/cgbm_trigger/ground/1356406433/index.html

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