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GCN Circular 35811

GRB 240225B: CALET Gamma-Ray Burst Monitor detection
2024-02-26T22:35:56Z (5 months ago)
Yuta Kawakubo at Louisiana State University <>
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Y. Kawakubo (LSU), A. Yoshida, T. Sakamoto, S. Sugita (AGU), 
K. Yamaoka (Nagoya U), S. Nakahira (JAXA),
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 240225B (MAXI/GSC detection: Nakajima et al., 
GCN Circ. 35796; AstroSat CZTI detection: Joshi et al., 35798)
was detected in the ground analysis of the CALET Gamma-ray 
Burst Monitor (CGBM) data around 20:12:08.50 on 25 February 
2024 (referenced to the AstroSat detection: GCN Circ. 35798)
The main episode that AstroSat CZTI detected was seen by all CGBM 
detectors. Also, a hint of emission that MAXI/GSC detected was seen 
in the HXM data around T+230 s.

The burst light curve of the main episode shows a multi-peaked 
structure that starts at T-7.6 sec, and ends at T+31.1 sec. The T90 
and T50 durations measured by the SGM data are 33.0 +/- 0.9 sec
and 17.1 +/- 1.3 sec (40-1000 keV), respectively.

The ground-processed light curve is available at

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