TITLE: GCN CIRCULAR NUMBER: 44246 SUBJECT: GRB 260407A: GECAM-A detection DATE: 26/04/09 11:19:26 GMT FROM: guohx@ihep.ac.cn Hao-Xuan Guo, Shao-Lin Xiong, Peng Zhang, Yan-Qiu Zhang, Chen-Wei Wang (IHEP) report on behalf of the GECAM team: GECAM-A detected a long burst, GRB 260407A, at 2026-04-07T09:11:07.950 UTC (denoted as T0), which was also observed by Fermi GBM (GCN #44226), Glowbug (C.C. Cheung et al., GCN #44237), CALET (M. L. Cherry et al., GCN #44242) and Insight-HXMT/HE (Hao-Xuan Guo et al., GCN #44245). According to the GECAM-A light curves in about 40-6000 keV, this burst mainly consists of a single pulse with a duration (T90) of 19.5 +4.5/-6.5 s. The GECAM-A light curve can be found here: https://www.bursthub.cn//admin/static/gecamagrb260407A.png Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission originally consists of two microsatellites (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).