2026-04-03T08:53:36.763Z | rev 0
Jin-Peng Zhang, Chen-Wei Wang, Shao-Lin Xiong (IHEP) report on behalf of GECAM team:
GECAM-B ground search was triggered by GRB 260402B, at 2026-04-02T22:57:17.100 UTC (denoted as T0), which is also detected by Fermi/GBM (Fermi GBM team, GCN #44193).
According to the GECAM-B light curves in about 70-6000 keV, this burst mainly consists of one pulse, with a duration (T90) of 2.0 +0.5/-1.0 s.
The GECAM-B light curve can be found here:
https://www.bursthub.cn//admin/static/gecambgrb260402B.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 44193: GRB 260402B: Fermi GBM Final Real-time Localization
2026-04-02T23:07:38.494Z | rev 0
The Fermi GBM team reports the detection of a likely LONG GRB
At 22:57:17 UT on 2 Apr 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260402B (trigger 796863442.54282 / 260402956).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 238.4, Dec = 0.2 (J2000 degrees, equivalent to J2000 15h 53m, 0d 12'), with a statistical uncertainty of 11.4 degrees.
The angle from the Fermi LAT boresight is 72.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260402956/quicklook/glg_skymap_all_bn260402956.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/bn260402956/quicklook/glg_healpix_all_bn260402956.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260402956/quicklook/glg_lc_medres34_bn260402956.gif