TITLE:   GCN CIRCULAR
NUMBER:  44100
SUBJECT: GRB 260316B: CALET Gamma-Ray Burst Monitor detection
DATE:    26/03/24 07:55:16 GMT
FROM:    Yuta Kawakubo at Aoyama Gakuin University <kawakubo@phys.aoyama.ac.jp>

T. Tamura (Kanagawa U), A. Yoshida, T. Sakamoto, S. Sugita, Y. Kawakubo (AGU),
K. Yamaoka (Nagoya U), S. Nakahira (JAXA), Y. Asaoka (ICRR), S. Torii,
Y. Akaike, K. Kobayashi (Waseda U), Y. Shimizu (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 GRB 260316B (Fermi GBM Final Real-time Localization: Fermi GBM 
team, GCN Circ. 44031; AstroSat CZTI detection: Harsha et al., GCN Circ. 
44035; SVOM/GRM observation: Wang et al., GCN Circ. 44039; GECAM-B 
observation: Wang et al., GCN Circ. 44040) triggered the CALET Gamma-ray
Burst Monitor (CGBM) at 17:12:52.15 UTC on 16 March 2026
(https://cgbm.calet.jp/cgbm_trigger/flight/1457716347/index.html).
The burst signal was seen by all CGBM detectors.  

The burst light curve shows a single pulse that starts
at T+0.38 sec, peaks at T+1.25 sec, and ends at T+2.37 sec.
The T90 and T50 durations measured by the SGM data are 1.75 +/- 0.18 sec
and 0.75 +/- 0.13 sec (40-1000 keV), respectively.

The ground-processed light curve is available at

https://cgbm.calet.jp/cgbm_trigger/ground/1457716347/

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