TITLE: GCN CIRCULAR NUMBER: 44778 SUBJECT: GRB 260601A: GECAM-B observation of a short burst DATE: 26/06/03 00:54:14 GMT FROM: Yue Wang Yue Wang, Chen-Wei Wang, Shao-Lin Xiong (IHEP) report on behalf of GECAM team: GECAM-B was triggered in-flight by GRB 260601A at 2026-06-01T11:00:12.500 UTC (denoted as T0), which is also detected by Fermi/GBM (Fermi GBM team, GCN #44755). According to the GECAM-B light curves in about 70-6000 keV, this burst mainly consists of muplti-pulses with a duration (T90) of 0.78 +0.21/-0.57 s. The GECAM-B light curve can be found here: https://www.bursthub.cn//admin/static/gecambgrb260601A.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).