TITLE:   GCN CIRCULAR
NUMBER:  44974
SUBJECT: GRB 260616C: GECAM-B observation of a burst
DATE:    26/06/18 07:27:43 GMT
FROM:    renyz16607@163.com

Yang-Zhao Ren, Chen-Wei Wang, Shao-Lin Xiong (IHEP) report on behalf of GECAM team:

GECAM-B was triggered on-ground by GRB 260616C, at 2026-06-16T14:47:01.950 UTC (denoted as T0), which is also detected by MAXI/GSC (Iwakiri et al., GCN #44961). 

According to the GECAM-B light curves in about 70-6000 keV, this burst mainly consists of a pulse with a duration (T90) of 29.5 +3.5/-4.5 s.

The GECAM-B light curve can be found here:
https://www.bursthub.cn//admin/static/gecambgrb260616C.png

The time-averaged spectrum from T0-4 s to T0+8 s is best fitted by a power law function. The power law index is -2.32 +0.16/-0.13. The event fluence (10-1000 keV) in this time interval is (1.99 +0.30/-0.26)E-04 erg/cm^2.

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).