TITLE: GCN CIRCULAR NUMBER: 42484 SUBJECT: GRB 251022A: SVOM/GRM observation DATE: 25/10/27 15:46:15 GMT FROM: renyz16607@163.com GRB 251022A: SVOM/GRM observation SVOM/GRM team: Yang-Zhao Ren, Chen-Wei Wang, Shi-Jie Zheng, Yue Huang, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP) SVOM/ECLAIRs team: Nicolas Dagoneau (CEA), Jean-Luc Atteia (IRAP) Report on behalf of the SVOM team: SVOM/GRM was triggered in-flight by GRB 251022A at 2025-10-22T22:34:19.000 UTC (T0), which is also detected by Fermi/GBM (Fermi GBM Team, GCN #42380), Swift/BAT (James DeLaunay et al., GCN#42409) and Fermi/LAT ( N. Di Lalla et al., GCN #42384), With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of multiple pulses with a T90 of 106 +6/-2 s in the 15-5000 keV band. The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb251022A.png In addition, the position of this burst, as determined by Fermi/GBM (RA = 74.5, Dec = -22.7, GCN #42380), is located at about 102 degrees from the SVOM optical axis, which is outside the ECLAIRs field of view. With this localization, the time-averaged spectrum from T0-20 to T0+101 s is best fitted by a power law function with an exponential high-energy cutoff. The power law index is -1.49 +0.12/-0.11 and the cutoff energy, parameterized as Epeak, is 330 +162/-80 keV. The event fluence (10-1000 keV) in this time interval is (4.07 +0.27/-0.27)E-05 erg/cm^2. The localization of GRB 251022A in the 'Amati' relation diagram is shown at: https://www.bursthub.cn//admin/static/svgrb251022A_amati.png The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. GRM is developed by the Institute of High Energy Physics (IHEP) of CAS. The SVOM point of contact for this burst is: Yang-Zhao Ren (IHEP)(renyz@ihep.ac.cn) View this GCN Circular online at https://gcn.nasa.gov/circulars/42484. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...