GRB 261008A
GCN Circular 45949
Subject
GRB 261008A: SVOM/GRM observation
Date
2026-10-14T12:36:50Z (2 days ago)
From
xueyuan zao <zaoxueyuan@gmail.com>
Via
Web form
SVOM/GRM team: Xue-Yuan Zao, Chen-Wei Wang, Shi-Jie Zheng, Yue Huang, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP)
SVOM/ECLAIRs team: Oliver Godet (IRAP)
Report on behalf of the SVOM team:
SVOM/GRM was triggered on-ground by GRB 261008A at 2026-10-08T18:19:08.250 UTC (T0), which is also detected by Fermi/GBM (Fermi GBM Team, GCN #45866) and GECAM-B (Zhang et al., GCN #45878).
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 1.8 +0.7/-0.6 s in the 15-5000 keV band.
The SVOM/GRM light curve can be found here:
https://www.bursthub.cn/gcn/2026/svgrb261008A.png
In addition, the position of this burst, as determined by Fermi/GBM (RA= 310.4, DEC=11.1, ERR=12.4 degrees), is located at about 49.9 degrees from the SVOM optical axis, which is outside the ECLAIRs field of view.
With this localization, the time-averaged spectrum from T0-1.15 to T0+0.95 s is best fitted by a power law function. The power law index is -1.59 +0.13/-0.14. The event fluence (10-1000 keV) in this time interval is (4.60 +1.07/-1.02)E-07 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: Xue-Yuan Zao (IHEP)(zaoxy@ihep.ac.cn)
GCN Circular 45875
Subject
GRB 261008A: GECAM-B observation
Date
2026-10-09T14:13:38Z (7 days ago)
From
zhangjinpeng@ihep.ac.cn
Via
Web form
Jin-Peng Zhang, Chen-Wei Wang, Shao-Lin Xiong (IHEP) report on behalf of GECAM team:
GECAM-B was triggered by GRB 261008A during routine ground search, at 2026-10-08T18:19:08.250 UTC (denoted as T0), which is also detected by Fermi/GBM (Fermi GBM team, GCN #45866).
According to the GECAM-B light curves in about 70-6000 keV, this burst mainly consists of one short pulse.
The GECAM-B light curve can be found here:
https://www.bursthub.cn/gcn/2026/gecambgrb261008A.png
Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission originally consists of two micro-satellites (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).
GCN Circular 45866
Subject
GRB 261008A: Fermi GBM Final Real-time Localization
Date
2026-10-08T18:29:38Z (8 days 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 SHORT GRB
At 18:19:08 UT on 8 Oct 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 261008A (trigger 813176353.292218 / 261008763).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 310.4, Dec = 11.1 (J2000 degrees, equivalent to J2000 20h 41m, 11d 05'), with a statistical uncertainty of 12.4 degrees.
The angle from the Fermi LAT boresight is 85.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn261008763/quicklook/glg_skymap_all_bn261008763.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn261008763/quicklook/glg_healpix_all_bn261008763.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn261008763/quicklook/glg_lc_medres34_bn261008763.gif