GRB 260507A
GCN Circular 44583
Subject
MASS-Cube (GRID 2.0) detection of GRB 260507A
Date
2026-05-12T16:33:06Z (3 days ago)
From
GRID Student Team at Tsinghua University <grid@tsinghua.edu.cn>
Via
Web form
Jiahuan Zhu, Chenyu Wang, Xutao Zheng, Hao Chang, Zirui Yang report on behalf of the MASS-Cube Collaboration:
MASS-Cube reports the detection of the long-duration GRB 260507A, which was also detected by Fermi/GBM (GCN Circular 44493) and GRID-09.
The event was triggered by MASS-Cube on 2026-05-07 at 20:27:59.7 UTC. The measured burst duration (T90) in the 50-10000 keV range is approximately 19.3 +/- 3.2 seconds.
The MASS-Cube light curve of this event can be found at https://mirrors.tuna.tsinghua.edu.cn/GRID/data/GRID-GCN/GRB260507A/MASS_Cube_260507A_ltcv.pdf.
MASS-Cube is a pathfinder for a 3D position-sensitive Compton telescope in space, currently considered the next generation of the GRID constellation in the era of multi-messenger astronomy. For more information about MASS-Cube, please refer to the following reference: https://doi.org/10.1007/s10686-024-09920-4.
GCN Circular 44493
Subject
GRB 260507A: Fermi GBM Final Real-time Localization
Date
2026-05-07T20:38:34Z (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 LONG GRB
At 20:28:00 UT on 7 May 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260507A (trigger 799878485.453562 / 260507853).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 287.5, Dec = -21.3 (J2000 degrees, equivalent to J2000 19h 10m, -21d 18'), with a statistical uncertainty of 2.4 degrees.
The angle from the Fermi LAT boresight is 79.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260507853/quicklook/glg_skymap_all_bn260507853.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/bn260507853/quicklook/glg_healpix_all_bn260507853.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260507853/quicklook/glg_lc_medres34_bn260507853.gif