GRB 251102B
GCN Circular 42621
Subject
GRB 251102B: SVOM/GRM observation
Date
2025-11-08T13:30:33Z (6 months ago)
From
yzh807926@163.com
Via
Web form
SVOM/GRM team: Zheng-Hang Yu, Chen-Wei Wang, Yue Huang, Shi-Jie Zheng, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP)
SVOM/ECLAIRs team: Sebastien Guillot (IRAP)
Report on behalf of the SVOM team:
SVOM/GRM was triggered on-ground by a burst GRB 251102B at 2025-11-02T21:15:53.000 UTC (T0), which is also detected by Fermi/GBM (Fermi GBM team, GCN #42533).
With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of a single peak with a T90 of 3.5 +1.5/-1.0 s in the 15-5000 keV band.
The SVOM/GRM light curve can be found here:
https://www.bursthub.cn//admin/static/svgrb251102B.png
In addition, the position of this burst, as determined by Fermi/GBM (RA= 110.6, DEC= -69.7, GCN#42533), is located at about 83 degrees from the SVOM optical axis, which is outside the ECLAIRs field of view.
With this localization, the time-averaged spectrum from T0-6 to T0+4 s is best fitted by a power law function. The power law index is -1.98 +0.01/-0.03. The event fluence (10-1000 keV) in this time interval is (1.25 +0.16/-0.15)E-6 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 point of contact for this burst is: Zheng-Hang Yu(IHEP)(zhyu@ihep.ac.cn)
GCN Circular 42533
Subject
GRB 251102B: Fermi GBM Final Real-time Localization
Date
2025-11-02T21:26:26Z (6 months ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
Via
email
The Fermi GBM team reports the detection of a likely LONG GRB
At 21:15:53 UT on 2 Nov 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251102B (trigger 783810958.850558 / 251102886).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 110.6, Dec = -69.7 (J2000 degrees, equivalent to J2000 07h 22m, -69d 42'), with a statistical uncertainty of 4.2 degrees.
The angle from the Fermi LAT boresight is 153.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251102886/quicklook/glg_skymap_all_bn251102886.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251102886/quicklook/glg_healpix_all_bn251102886.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251102886/quicklook/glg_lc_medres34_bn251102886.gif