TITLE: GCN CIRCULAR NUMBER: 35157 SUBJECT: GRB 231122B: GECAM detection DATE: 23/11/22 16:23:45 GMT FROM: Chenwei Wang at IHEP Chen-Wei Wang, Shao-Lin Xiong report on behalf of the GECAM team: GECAM-B was triggered in-flight by a long burst, GRB 231122B at 2023-11-22T15:12:41.050 UTC (denoted as T0), which was also detected by CALET/GBM (trigger num 1384701074). According to the realtime alert data of GECAM-B, this burst mainly consists of many pulses with a duration of about 50 s. The time-averaged spectrum from T0 to T0+17 s could be adequately fit by a power law with high energy exponential cutoff function with a fluence of about 9.8E-6 erg/cm2 in 20-1000 keV. Using the automatic on-ground localization pipeline with the realtime alert data, GECAM-B localized this burst to the following position (J2000): Ra: 106.2 deg Dec: -21.3 deg Err: 1.5 deg (1-sigma, statistical only) 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).