GCN 43605: GRID detection of GRB 260131A/B

Longhao Li, Zirui Yang, Chenyu Wang report on behalf of the GRID Collaboration:

GRID reports the detection of GRB 260131A/B, which was also reported by Fermi and MAXI (Roberts, GCN 43585; a.k.a. GRB 260131B, Sugai et al., GCN 43580).

The event first triggered GRID at T0 = 2026-01-31 06:39:30 UTC, and was detected by both GRID-10B and GRID-11B, with a weaker signal observed by GRID-11B. A second trigger was recorded at 2026-01-31 06:43:02 UTC; however, the GRID signal associated with this later trigger is comparatively weak. Therefore, temporal analysis is based on the first trigger only.

The measured burst duration for the first trigger is T90 = 10.5 ± 1.4 s in the 30–2000 keV energy range.

The GRID light curves of this event can be found at https://mirrors.tuna.tsinghua.edu.cn/GRID/data/GRID-GCN/GRB260131A-B/.  

GRID is a student-led project to monitor the transient gamma-ray sky with multiple detectors onboard different nanosatellites in the era of multi-messenger astronomy. For more information about GRID, please refer to the following references: https://doi.org/10.1007/s10686-019-09636-w and https://doi.org/10.1007/s10686-021-09819-4.