GRB 260705B
GCN Circular 45116
Subject
GRB 260705B: SVOM/GRM observation
Date
2026-07-08T16:19:53Z (a day ago)
From
Xinghao Luo at IHEP <2952704891@qq.com>
Via
Web form
SVOM/GRM team: Xing-Hao Luo, Chen-Wei Wang, Yue Huang, Shi-Jie Zheng, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP)
SVOM/ECLAIRs team: Nicolas Dagoneau (CEA)
Report on behalf of the SVOM team:
SVOM/GRM was triggered on-ground by GRB 260705B at 2026-07-05T22:46:39.000 UTC (T0), which is also detected by Fermi/GBM (Fermi GBM team, GCN #45081).
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 99 +12/-9 s in the 15-5000 keV band.
The SVOM/GRM light curve can be found here:
https://www.bursthub.cn//admin/static/svgrb260705B.png
In addition, the position of this burst, as determined by Fermi/GBM (RA=68.5 , DEC=-30.8, with a statistical uncertainty of 3.0 degrees, Fermi GBM team, GCN #5081), is located at about 74 degrees form the SVOM optical axis, which is outside the ECLAIRs field of view.
With this localization, the time-averaged spectrum from T0-24 to T0+75 s is best fitted by a power law function. The power law index is -1.84 +/-0.06. The event fluence (10-1000keV) in this time interval is (1.11 +0.19/-0.16)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 point of contact for this burst is: Xing-Hao Luo (luoxh@ihep.ac.cn)
GCN Circular 45081
Subject
GRB 260705B: Fermi GBM Final Real-time Localization
Date
2026-07-06T00:19:12Z (4 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 LONG GRB
At 22:46:36 UT on 5 Jul 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260705B (trigger 804984401.559966 / 260705949).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 68.5, Dec = -30.8 (J2000 degrees, equivalent to J2000 04h 33m, -30d 48'), with a statistical uncertainty of 3.0 degrees.
The angle from the Fermi LAT boresight is 77.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260705949/quicklook/glg_skymap_all_bn260705949.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/bn260705949/quicklook/glg_healpix_all_bn260705949.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260705949/quicklook/glg_lc_medres34_bn260705949.gif