GCN Circular 44726
Subject
GRB 260527A: CALET Gamma-Ray Burst Monitor detection
Event
Date
2026-05-28T17:22:16Z (a day ago)
From
Yuta Kawakubo at Aoyama Gakuin University <kawakubo@phys.aoyama.ac.jp>
Via
Web form
Y. Kawakubo, 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), M. L. Cherry (LSU), S. Ricciarini (U of Florence),
P. S. Marrocchesi (U of Siena),
and the CALET collaboration:
The CALET Gamma-ray Burst Monitor (CGBM) detected the short GRB 260527A
(Konus-Wind detection: Svinkin et al., GCN #44722; GECAM-B detection:
Yu et al., GCN #44724) at 06:16:09.76 UTC on 27 May 2026
(https://cgbm.calet.jp/cgbm_trigger/flight/1463897683/index.html).
The burst signal was seen by all CGBM detectors.
The burst light curve shows a multi-peaked structure starting
at T+0.16 s, peaking at T+0.28 s, and ending at T+0.38 s.
The T90 and T50 durations measured with the SGM data are 0.19 +/- 0.04 s
and 0.06 +/- 0.02 s (40-1000 keV), respectively.
Einstein Probe/WXT detected a fast X-ray transient, EP 260527a
(Yang et al., GCN #44718), about 4 minutes before the CGBM trigger,
and Einstein Probe/FXT follow-up observations were also reported by Yang et al.
(GCN Circ. 44725). The position of EP 260527a was observable by CGBM
at the CGBM trigger time, with an incident angle of approximately 40 degrees.
The ground-processed light curve is available at
https://cgbm.calet.jp/cgbm_trigger/ground/1463897683/
The CALET data used in this analysis were provided by
the Waseda CALET Operation Center located at Waseda University.