TITLE: GCN CIRCULAR NUMBER: 42894 SUBJECT: GRB 251128A: SVOM/GRM observation of a long burst DATE: 25/11/29 14:47:25 GMT FROM: zhangjinpeng@ihep.ac.cn SVOM/GRM team: Jin-Peng Zhang, Chen-Wei Wang, Shi-Jie Zheng, Yue Huang, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP) SVOM/ECLAIRs team: Jean-Luc Atteia (IRAP) Report on behalf of the SVOM team: SVOM/GRM on-ground search was triggered by GRB 251128A at 2025-11-28T04:22:24.000 (T0), which is also detected by Fermi/GBM (Fermi GBM Team, GCN #42865). The GRM light curve shows that this burst consists of multiple pulses with a T90 of 47 +8/-5 s in the 15-5000 keV band. The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb251128A.png In addition, the position of this burst, as determined by Fermi/GBM (RA=117.5, Dec = 52.2, GCN #42865), is located at about 139.4 degrees from the SVOM optical axis, which is out of the ECLAIRs field of view. With this localization, the time-averaged spectrum from T0-10 to T0+45 s is best fit by a power law function. The power law index is -2.36 +0.22/-0.28. The event fluence (10-1000 keV) in this time interval is (3.08 +0.34/-0.35)E-05 erg/cm^2. 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/GRM point of contact for this burst is: Jin-Peng Zhang (IHEP) (zhangjinpeng@ihep.ac.cn) View this GCN Circular online at https://gcn.nasa.gov/circulars/42894. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...