TITLE: GCN CIRCULAR NUMBER: 31382 SUBJECT: GRB 220104A:GECAM detection DATE: 22/01/04 08:29:45 GMT FROM: Guoying Zhao at IHEP Z. W. Guo, S. L. Xiong, C. Cai, S. Xiao, P. Zhang, C. Y. Li, S. L. Xie, X. Y. Zhao, Y. Huang, X. Y. Song, J. C. Liu, Y. Zhao, Y. Q. Zhang, C. Zheng, W. C. Xue, C. W. Wang, Q. B. Yi, B. X. Zhang, W. X. Peng, R. Qiao, D. Y. Guo, X. B. Li, X. Ma, L. M. Song, 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, H. M. Zhang, Z. H. An, M. Gao, K. Gong, B. Li, C. Li, J. H. Li, X. Q. Li, Y. G. Li, X. H. Liang, X. J. Liu, Y. Q. Liu, X. L. Sun, Y. L. Tuo, J. Z. Wang, X. Y. Wen, Y. B. Xu, Y. P. Xu, S. Yang, C. Y. Zhang, D. L. Zhang, Fan Zhang, Fei Zhang, X. Zhou, F. J. Lu, S. N. Zhang (IHEP) report on behalf of GECAM team: During the commissioning phase, GECAM-B was triggered in-flight by a long bright burst, GRB 220104A, at 2022-01-04T04:01:02.850 UTC (denoted as T0), which was also observed by Fermi/GBM (GCN #31380). According to the BDS alert data, this burst mainly consists of a broad pulse with a duration of about 2 s. The GECAM light curve could be found here: http://twiki.ihep.ac.cn/pub/GECAM/GRBList/gecamb_lc_grd_all_combine_94968062.png GECAM-B localized this burst to the following position (J2000): ra: 192.9 deg dec: 37.3 deg err: 10.1 deg (1-sigma, statistical only) The current systematic error of location is estimated to be several degrees which could be minimized by the ongoing calibration. The GECAM preliminary location could be found here: http://twiki.ihep.ac.cn/pub/GECAM/GRBList/gecamb_sky_fit_94968062.png This position is consistent with the Fermi GBM team localization (trigger #662961667) 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).