TITLE: GCN CIRCULAR NUMBER: 45514 SUBJECT: GRB 260830A: GECAM-B detection of a burst DATE: 26/09/04 12:12:21 GMT FROM: yzh807926@163.com Zheng-Hang Yu, Shao-Lin Xiong (IHEP) report on behalf of GECAM team: GECAM-B was triggered in-flight by a burst GRB 260830A at 2026-08-30T19:32:11.800 UTC (denoted as T0), which is also detected by NuSTAR (G. Waratkar et al., GCN #45483) and Insight-HXMT/HE (Yu et al., GCN #45511). According to the GECAM-B light curves in about 70-6000 keV, this burst mainly consists of multiple pulses with a duration (T90) of 11 +/-1 s. The on-ground localization of GECAM-B is: Ra: 245.5 deg Dec: -61.1 deg Err: 3.4 deg (1-sigma, statistical only) The GECAM-B light curve can be found here: https://www.bursthub.cn/gcn/2026/gecambgrb260830A.png The time-averaged spectrum from T0-5.0 to T0+10.0 s is best fitted by a power law function with an exponential high-energy cutoff. The power law index is -1.13 +0.30/-0.28 and the cutoff energy, parameterized as Epeak, is 190 +23/-14 keV. The event fluence (10-1000 keV) in this time interval is (1.85 +0.25/-0.18) E-05 erg/cm^2. The localization of GRB 260830A in the 'Amati' relation diagram is shown at: https://www.bursthub.cn/gcn/2026/gecambgrb260830A_amati.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). View this GCN Circular online at https://gcn.nasa.gov/circulars/45514. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...