GRB 210207B: GECAM detection

During the commissioning phase, the ground search of GECAM-B data found a long burst, GRB 210207B, at 2021-02-07T21:52:14.050 UTC (T0), which was also reported by Swift/BAT (GCN #29420, #29435), Konus/Wind (GCN #29426), AGILE (GCN #29428) and Insight-HXMT/HE (GCN #29434). The later bright pulse also triggered GECAM-B in-flight. According to the GECAM-B light curves in about 8 keV-4 MeV, this burst mainly consists of multiple pulses with a duration (T90) of 45.0 +/- 4.5 s starting from T0 - 1.8 s. The 1-s peak counts rate is about 1300 cps while the total counts is about 4600 counts. Although the in-flight calibration of energy response and localization has not been finalized yet, GECAM-B localized this burst to the following position (J2000): Ra: 275.00 deg Dec: 51.57 deg Err: 8.23 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. This position is consistent with Swift (GCN #29420) within the error. The GECAM light curve could be found here: http://twiki.ihep.ac.cn/pub/GECAM/GRBList/GECAM-B-tn210207_215215.pdf 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).