GRB 261009A
GCN Circular 45948
Subject
GRB 261009A: GECAM-B detection of a burst
Date
2026-10-14T12:32:52Z (2 days ago)
From
xueyuan zao <zaoxueyuan@gmail.com>
Via
Web form
Xue-Yuan Zao, Chao Zheng, Shao-Lin Xiong (IHEP) report on behalf of GECAM team:
GECAM-B was triggered on-ground by the burst GRB 261009A at 2026-10-09T22:19:12.000 UTC (denoted as T0), which is also detected by Fermi/GBM (Fermi GBM Team, GCN #45879). According to the GECAM-B light curves in about 70-6000 keV, this burst mainly consists of multiple pulses with a duration (T90) of 17.0 +5.0/-4.5 s.
The on-ground localization of GECAM-B is:
Ra: 125.8 deg
Dec: 45.4 deg
Err: 10.7 deg (1-sigma, statistical only)
The GECAM-B light curve can be found here:
https://www.bursthub.cn/gcn/2026/gecambgrb261009A.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 45879
Subject
GRB 261009A: Fermi GBM Final Real-time Localization
Date
2026-10-09T22:29:42Z (7 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 22:19:11 UT on 9 Oct 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 261009A (trigger 813277156.325786 / 261009930).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 116.9, Dec = 45.5 (J2000 degrees, equivalent to J2000 07h 47m, 45d 30'), with a statistical uncertainty of 3.2 degrees.
The angle from the Fermi LAT boresight is 12.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn261009930/quicklook/glg_skymap_all_bn261009930.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/bn261009930/quicklook/glg_healpix_all_bn261009930.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn261009930/quicklook/glg_lc_medres34_bn261009930.gif