TITLE: GCN CIRCULAR NUMBER: 31071 SUBJECT: GRB 211107A: GECAM detection DATE: 21/11/10 07:26:02 GMT FROM: Y Q Zhang at IHEP <yqzhang@ihep.ac.cn> Y. Q. Zhang, S. L. Xiong, S. Xiao, C. Cai, X. Y. Zhao, Y. Huang, X. Y. Song, J. C. Liu, S. L. Xie, Y. Zhao, Z. W. Guo, C. Zheng, W. C. Xue, C. Y. Li, C. W. Wang, Q. B. Yi, B. X. Zhang, P. Zhang, W. X. Peng, R. Qiao, D. Y. Guo, X. B. Li, X. Ma, P. Wang, J. Wang, Z. Zhang, S. J. Zheng, W. Chen, J. J. He, G. Y. Zhao, Y. Q. Du, H. Wu, J. Liang, Q. Luo, X. L. Zhang, L. M. Song, F. J. Lu, S. N. Zhang (IHEP), report on behalf of GECAM team: During the commissioning phase, GECAM-B was triggered on-ground by a weak burst, GRB 211107A, at 2021-11-07T20:20:40.220 UTC (denoted as T0), which was also observed by Fermi/GBM (GCN #31052). According to the GECAM-B light curves in about 20-500 keV, this burst mainly consists of multiple pulses with a duration of 5 s. The GECAM light curve could be found here: http://twiki.ihep.ac.cn/pub/GECAM/GRBList/gecamb_lc_grd_90015640_v01.PNG GECAM location is consistent with the Fermi/GBM position within the error. Please note that all GECAM results here are preliminary. The final analysis will be published in journal papers or GECAM online catalog. Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission consists of two small satellites (GECAM-A and GECAM-B) in Low Earth Orbit (600 km, 29 deg), launched on Dec 10, 2020 (Beijing Time), which was funded by the Chinese Academy of Sciences (CAS).