GCN Circular 41648
Subject
GRB 250902A: Fermi GBM Final Real-time Localization
Event
Date
2025-09-02T01:40:30Z (10 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 01:30:00 UT on 2 Sep 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250902A (trigger 778469405.491528 / 250902062).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 159.3, Dec = 16.3 (J2000 degrees, equivalent to J2000 10h 37m, 16d 18'), with a statistical uncertainty of 1.0 degrees.
The angle from the Fermi LAT boresight is 78.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250902062/quicklook/glg_skymap_all_bn250902062.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/bn250902062/quicklook/glg_healpix_all_bn250902062.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250902062/quicklook/glg_lc_medres34_bn250902062.gif