TITLE:   GCN CIRCULAR
NUMBER:  42895
SUBJECT: GRB 251128A: GECAM-B detection
DATE:    25/11/29 15:11:17 GMT
FROM:    zhangjinpeng@ihep.ac.cn

Jin-Peng Zhang, Jia-Cong Liu, Chen-Wei Wang, Chao Zheng, Shao-Lin Xiong (IHEP) report on behalf of GECAM team:

GECAM-B was triggered in-flight by a long burst, GRB 251128A, at 2025-11-28T04:22:22.950 UTC (denoted as T0), which is also detected by Fermi/GBM (Fermi GBM team, GCN #42865).

According to the GECAM-B light curves in about 40-6000 keV, this burst mainly consists of multiple pulses with a duration (T90) of 46 +2/-4 s.

The GECAM-B light curve can be found here:
https://www.bursthub.cn//admin/static/gecambgrb251128A.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).