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GCN Circular 33049

Subject
GRB 221209A: CALET Gamma-Ray Burst Monitor detection
Date
2022-12-12T23:03:08Z (a year ago)
From
Yuta Kawakubo at Louisiana State U./CALET <kawakubo1@lsu.edu>
Y. Kawakubo (LSU), A. Yoshida, T. Sakamoto, S. Sugita (AGU), 
K. Yamaoka (Nagoya U), 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 221209A (Fermi GBM Final Real-time Localization: 
Fermi GBM team, GCN Circ. 33031; BALROG localization:
Kunzweiler et al., GCN Circ 33032; Fermi GBM observation: 
Bissaldi et al., GCN Circ 33034; AstroSat CZTI detection: 
Gopalakrishnan et al., GCN Circ 33037) triggered the CALET Gamma-ray
Burst Monitor (CGBM) at 05:50:25.591 UTC on 9 December 2022
(http://cgbm.calet.jp/cgbm_trigger/flight/1354600238/index.html).
The burst signal was seen by all CGBM detectors.
No real-time CGBM GCN notice was distributed about this trigger because
the real-time communication from the ISS was off (loss of signal).

The burst light curve shows a single pulse that starts
at T-2.0 sec, peaks at T+0.9 sec, and ends at T+5.0 sec.
The T90 and T50 durations measured by the SGM data are 3.2 +/- 0.4 sec
and 1.3 +/- 0.1 sec (40-1000 keV), respectively.

The ground-processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1354600238/

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