TITLE:   GCN CIRCULAR
NUMBER:  45805
SUBJECT: GRB 260921B: GECAM-B observation
DATE:    26/10/03 13:36:38 GMT
FROM:    guohx@ihep.ac.cn

Hao-Xuan Guo, Jin-Ye Luo, Chen-Wei Wang, Chao Zheng, Shao-Lin Xiong (IHEP) report on behalf of GECAM team:

GECAM-B was triggered on-ground by GRB 260921B, at 2026-09-21T21:44:41.950 UTC (denoted as T0), which is also detected by Fermi/GBM (Fermi GBM team, GCN #45685).

According to the GECAM-B light curves in about 70-6000 keV, this burst mainly consists of multiple pulses with a duration (T90) of 46 +4/-7 s.

The GECAM-B light curve can be found here:
https://www.bursthub.cn/gcn/2026/gecambgrb260921B.png

Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission originally consists of two micro-satellites (GECAM-A and GECAM-B) launched in Dec. 2020. As the third member of GECAM constellation, GECAM-C was launched onboard SATech-01 experimental satellite in July 2022. GECAM mission is funded by the Chinese Academy of Sciences (CAS).