TITLE: GCN CIRCULAR NUMBER: 39492 SUBJECT: GRB 250226A: GECAM-B detection DATE: 25/02/26 14:05:27 GMT FROM: yqzhang_cl@163.com GRB 250226A: GECAM-B detection Yan-Qiu Zhang (IHEP), Shao-Lin Xiong (IHEP), Chen-Wei Wang (IHEP) report on behalf of the GECAM team: GECAM-B was triggered both in-flight and on-ground by a long burst, GRB 250226A, at 2025-02-26T06:34:56.000 UTC (T0), which was also detected by Fermi/GBM (Fermi GBM team, GCN #39479), EP/WXT (EP250226a/GRB 250226A, S.Q. Jiang et al., GCN #39482) and INTEGRAL/SPI-ACS (triNum #11070). According to the GECAM-B light curves in about 5-2000 keV, this burst mainly consists of multiple pulses with a duration (T90) of about 63.5 +/- 11.7 s. The GECAM light curve could be found here: https://www.bursthub.cn//admin/static/gecamgrb250226A.png We note that these results are very preliminary. Refined analysis will be reported later. Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission originally consists of two microsatellites (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).