TITLE: GCN CIRCULAR NUMBER: 39369 SUBJECT: GRB 250217C: SVOM/GRM observation DATE: 25/02/19 03:52:28 GMT FROM: Chenwei Wang at IHEP cwwang@ihep.ac.cn
SVOM/GRM team: Chen-Wei Wang, Shi-Jie Zheng, Shao-Lin Xiong, Yue Huang, Shuang-Nan Zhang (IHEP)
SVOM/ECLAIRs team: Frédéric Piron (LUPM), Nicolas Dagoneau (CEA), Maria-Grazia Bernardini (INAF-OAB), Jean-Luc Atteia, Sébastien Guillot (IRAP)
report on behalf of the SVOM team:
SVOM/GRM was triggered in-flight by a short burst GRB 250217C (sb25021704) at 2025-02-17T23:54:41.900 UTC (T0), which was also observed by Fermi/GBM (Fermi GBM team, GCN #39357), AstroSat (M. Tembhurnikar et al., GCN #39359), Konus-Wind, HEND/Mars and INTEGRAL SPI-ACS (A.S. Kozyrev et al., GCN #39365).
With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of multi-pulses with a T90 of about 0.42 +0.07/-0.22 seconds in the 15-5000 keV.
The time-averaged spectrum from T0-0.2 to T0+0.2 s could be fit by a Band function with alpha = -0.61 +/- 0.3, beta = -1.87 +/- 0.07 and Epeak = 77 +20/-11 keV. The event fluence (10-1000 keV) in this time interval is (1.40 +/- 0.71)E-06 erg/cm^2.
The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb250217C.png
In addition, the position of this burst, as determined by Fermi/GBM (Fermi GBM Team, GCN #39357), is located at about 50 degrees from the SVOM optical axis, right at the edge of the ECLAIRs field of view.
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: Chen-Wei Wang (IHEP) (cwwang@ihep.ac.cn)
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