GRB 261108A
GCN Circular 46186
Subject
GRB 261108A: SVOM detection of a burst
Date
2026-11-08T01:54:22Z (4 minutes ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
Wenjin Xie (NAOC), Xin Feng (GXU), Youdong Hu (GXU), Clara Plasse (HKU), Hatsune Goto (RIKEN/CEA) report on behalf of the SVOM mission team:
At 2026-11-08T01:13:20 UTC (T0), SVOM/ECLAIRs triggered and located the gamma-ray burst GRB 261108A (SVOM burst-id sb26110802). The following trigger information was received on the ground with low latency by the SVOM VHF Alert Network.
The burst was detected both by the Count-Rate Trigger (CRT) and the Image Trigger (IMT), which produced a sequence of 18 alerts. CRT provided the alert with the best signal-to-noise-ratio in the image (SNR) of 17.68 in the [8-50] keV energy band over a time window of 10.20 seconds starting at 2026-11-08T01:13:17.
The localization of the best alert is R.A., Dec. 336.5157, -20.2077 degrees:
R.A. (J2000) = 22h26m03.78s
Dec. (J2000) = -20d12m27.78s
with a 90% confidence level (C.L.) radius of 4.79 arcmin (including systematic error of 2 arcmin added in quadrature).
This burst was also detected by SVOM/GRM with a significance of 17.30. The SVOM/GRM light curve showed a single peak structure with a T90 duration of about 9.33 (-1.42 +1.95) s.
This burst is consistent in time and position with Fermi/GBM detection at 01:13:19 UTC (GCN #46185).
SVOM slewed to the burst. SVOM/MXT and VT started observation. The analysis of the data will be published in a future circular.
The Space-based multi-band astronomical Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA), French Space Agency (CNES), and the Chinese Academy of Sciences (CAS), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. SVOM/ECLAIRs was developed jointly by CNES, CEA-IRFU, CNRS-IRAP, CNRS-APC. SVOM/GRM was developed by the Institute of High Energy Physics (IHEP) of CAS. SVOM/MXT was developed jointly by CNES, CEA-IRFU, CNRS-IJCLab, University of Leicester, MPE.
The Burst Advocate (BA) on shift for this alert is Clara Plasse: cplasse@hku.hk.
Please contact the BA by email if you require additional information.
GCN Circular 46185
Subject
GRB 261108A: Fermi GBM Final Real-time Localization
Date
2026-11-08T01:24:01Z (34 minutes 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 01:13:19 UT on 8 Nov 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 261108A (trigger 815793204.346972 / 261108051).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 338.7, Dec = -22.4 (J2000 degrees, equivalent to J2000 22h 34m, -22d 23'), with a statistical uncertainty of 15.6 degrees.
The angle from the Fermi LAT boresight is 40.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn261108051/quicklook/glg_skymap_all_bn261108051.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/bn261108051/quicklook/glg_healpix_all_bn261108051.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn261108051/quicklook/glg_lc_medres34_bn261108051.gif