GCN Circular 42449
Subject
GRB 251025C: Fermi GBM Final Real-time Localization
Event
Date
2025-10-25T23:19:13Z (4 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 23:08:40 UT on 25 Oct 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251025C (trigger 783126525.293544 / 251025964).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 170.7, Dec = 54.9 (J2000 degrees, equivalent to J2000 11h 22m, 54d 53'), with a statistical uncertainty of 2.2 degrees.
The angle from the Fermi LAT boresight is 103.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251025964/quicklook/glg_skymap_all_bn251025964.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/bn251025964/quicklook/glg_healpix_all_bn251025964.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251025964/quicklook/glg_lc_medres34_bn251025964.gif