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GCN Circular 33322

Subject
GRB 230204B: CALET Gamma-Ray Burst Monitor detection
Date
2023-02-14T06:18:39Z (a year ago)
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 230204B (MAXI/GSC Detection: Serino et al., GCN Circ. 33265;
Swift/BAT-GUANO detection: Kennea et al., GCN Circ. 33267; AstroSat CZTI
detection: Waratkar et al., GCN Circ. 33268; AGILE detection: Casentini et al.,
GCN Circ. 33272; Detection by GRBAlpha: Dafcikova et al., GCN Circ. 33273;
Fermi-GBM Detection: Poolakkil et al., GCN Circ. 33288) triggered
the CALET Gamma-ray Burst Monitor (CGBM) at 21:44:25.20 UTC 
on February 4, 2023
(http://cgbm.calet.jp/cgbm_trigger/flight/1359582171/index.html).
The burst signal was seen by only the SGM detector.

The burst light curve shows a double-peaked structure that starts
at T+2.3 sec, peaks at T+54.1 sec and ends at T+65.0 sec.
The T90 and T50 durations measured by the SGM data are 59.5 +/- 0.9 sec
and 11.6 +/- 0.8 sec (40-1000 keV), respectively.

The ground-processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1359582171/

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