TITLE:   GCN CIRCULAR
NUMBER:  32125
SUBJECT: GRB 220525A: CALET Gamma-Ray Burst Monitor detection
DATE:    22/05/26 14:54:18 GMT
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 220525A (Fermi GBM Final Real-time Localization: Fermi GBM team,
GCN Circ. 32112; BALROG localization: Kunzweiler et al., GCN Circ 32113; 
IPN triangulation: Kozyrev et al., GCN Circ 32118; Konus-Wind detection: 
Frederiks et al., GCN Circ 32122) triggered the CALET Gamma-ray
Burst Monitor (CGBM) at 00:10:52.713 UTC on 25 May 2022
(http://cgbm.calet.jp/cgbm_trigger/flight/1337472486/index.html).
The burst signal was seen by only SGM detector.

The burst light curve shows a double-peaked structure which starts
at T+1.6 sec, peaks at T+4.7 sec, and ends at T+8.7 sec.
The T90 and T50 durations measured by the SGM data are 6.0 +/- 0.4 sec
and 2.6 +/- 0.5 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1337472486/

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