GRB 251005B
GCN Circular 42143
Subject
GRB 251005B: Glowbug gamma-ray detection
Date
2025-10-07T15:50:03Z (a day ago)
From
C.C. Cheung at Naval Research Lab <Teddy.Cheung@nrl.navy.mil>
Via
Web form
C.C. Cheung, R. Woolf, M. Kerr, J.E. Grove (NRL), A. Goldstein (USRA), C.A. Wilson-Hodge, D. Kocevski (MSFC), and M.S. Briggs (UAH) report:
The Glowbug gamma-ray telescope [1,2,3], operating on the International Space Station, reports the detection of GRB 251005B, which was also detected by Fermi/GBM (GCN 42112).
Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2025-10-05 14:27:57.168 with a duration of 6.1 s and a total significance of about 14.1 sigma. The Glowbug onset is ~38 s after the Fermi/GBM trigger time (14:27:19) and corresponds to the second, brighter peak seen in the Fermi/GBM light curve. A search of the Glowbug data for the initial fainter peak at the Fermi/GBM T0 was inconclusive.
The analysis results presented here are preliminary and use a response function that lacks a detailed characterization of the surrounding passive structure of the ISS.
Glowbug is a NASA-funded technology demonstrator for sensitive, low-cost gamma-ray transient telescopes developed, built, and operated by the U.S. Naval Research Laboratory (NRL) with support from the University of Alabama in Huntsville, USRA, and NASA MSFC. It was launched on 2023 March 15 aboard the Department of Defense Space Test Program’s STP-H9 to the ISS, and operated until 2024 April when it was put in safe storage on orbit. Glowbug was recently removed from storage and resumed operation on 2025 September 12.
[1] Grove, J.E. et al. 2020, Proc. Yamada Conf. LXXI, arXiv:2009.11959
[2] Woolf, R.S. et al. 2022, Proc. SPIE, 12181, id. 121811O
[3] Woolf, R.S. et al. 2024, Proc. SPIE, 13151, id. 1315108
Distribution Statement A: Approved for public release. Distribution is unlimited.
GCN Circular 42112
Subject
GRB 251005B: Fermi GBM Final Real-time Localization
Date
2025-10-05T14:37:49Z (3 days ago)
Edited On
2025-10-05T18:30:25Z (3 days ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
Edited By
Vidushi Sharma at NASA GSFC/UMBC <vidushi.sharma@nasa.gov>
Via
email
The Fermi GBM team reports the detection of a likely LONG GRB
At 14:27:19 UT on 5 Oct 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251005B (trigger 781367244.128264 / 251005602).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 298.6, Dec = -8.9 (J2000 degrees, equivalent to J2000 19h 54m, -8d 54'), with a statistical uncertainty of 6.5 degrees.
The angle from the Fermi LAT boresight is 104.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251005602/quicklook/glg_skymap_all_bn251005602.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251005602/quicklook/glg_healpix_all_bn251005602.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251005602/quicklook/glg_lc_medres34_bn251005602.gif