TITLE:   GCN CIRCULAR
NUMBER:  43644
SUBJECT: GRB 260207B: GECAM-B observation
DATE:    26/02/08 14:58:40 GMT
FROM:    xueyuan zao <zaoxueyuan@gmail.com>

Xue-Yuan Zao, Xing-Hao Luo, Chen-Wei Wang, Shao-Lin Xiong (IHEP) report on behalf of GECAM team:

GECAM-B was triggered in-flight and on-ground by GRB 260207B, at 2026-02-07T13:12:10.850 UTC, which is also detected by Fermi/GBM (Fermi GBM team, GCN #43629).

According to the GECAM-B light curves in about 70-6000 keV, this burst mainly consists of a short spike (Main Emission, ME) followed by an extended emission (EE) with a total duration (T90) of 65 +23/-9.5 s.

The GECAM-B light curve can be found here:
https://www.bursthub.cn//admin/static/gecambgrb260207B.png

The ME from T0 - 0.07 to T0 + 0.19 s is best fitted by a power law function with an exponential high-energy cutoff. The power law index is -1.15 +0.29/-0.32 and the cutoff energy, parameterized as Epeak, is 345 +151/-70 keV. The event fluence (10-1000 keV) in this time interval is (2.04 +/-0.22)E-06 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).