GCN 44187: GRB 260401A: GECAM-B observation

2026-04-02T15:01:22.185Z | rev 0 | event: GRB 260401A
Yang-Zhao Ren, Chen-Wei Wang, Shao-Lin Xiong (IHEP) report on behalf of GECAM team:

GECAM-B was triggered on-ground by GRB 260401A, at 2026-04-01T10:53:29.200 UTC (denoted as T0), which is also detected by Fermi/GBM (Fermi GBM Team, GCN #44174), MAXI/GSC (Usuki et. al., GCN #44176), CALET/GBM (Cannady et al., GCN #44177), and NuSTAR (Waratkar et al., GCN #44178). 

According to the GECAM-B light curves in about 70-6000 keV, this burst mainly consists of multiple pulses with a duration (T90) of 28.8 +0.1/-0.2 s.

The GECAM-B light curve can be found here:
https://www.bursthub.cn//admin/static/gecambgrb260401A.png

The time-averaged spectrum from T0 to T0 + 15 s is best fitted by a power law function. The power law index is -1.51 +0.08/-0.07. The event fluence (10-1000 keV) in this time interval is (2.20 +0.11/-0.10) E-05 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).