[vsnet-grb-info 28404] GRB 210725A: CALET Gamma-Ray Burst Monitor detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  30507
SUBJECT: GRB 210725A: CALET Gamma-Ray Burst Monitor detection
DATE:    21/07/25 10:59:46 GMT
FROM:    Valentin Pal'shin at AGU  <val at phys.aoyama.ac.jp>

S. Torii (Waseda U),
A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
Y. Asaoka (ICRR), 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 210725A (Swift detection: Bernardini et al., GCN Circ. 30501;
https://gcn.gsfc.nasa.gov/other/210725A.gcn3) triggered the CALET
Gamma-ray Burst Monitor (CGBM) at 03:47:01.565 UTC on 25 July 2021
(http://cgbm.calet.jp/cgbm_trigger/flight/1311219774/index.html).
The burst signal was seen only by the SGM detector.

The burst light curve shows a single weak pulse which starts at T+1.4 sec,
peaks at T+1.5 sec,and ends at T+6.9 sec. The T90 and T50 durations
measured by the SGM data are 5.0 +- 0.7 sec and 3.0 +- 0.9 sec
(40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1311219774/

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