TITLE:   GCN CIRCULAR
NUMBER:  42221
SUBJECT: GRB 251013C: Fermi GBM Final Real-time Localization
DATE:    25/10/13 17:50:11 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 17:39:41 UT on 13 Oct 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251013C (trigger 782069986.941944 / 251013736).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 348.9, Dec = -6.3 (J2000 degrees, equivalent to J2000 23h 15m, -6d 17'), with a statistical uncertainty of 5.0 degrees.

The angle from the Fermi LAT boresight is 65.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251013736/quicklook/glg_skymap_all_bn251013736.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/bn251013736/quicklook/glg_healpix_all_bn251013736.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251013736/quicklook/glg_lc_medres34_bn251013736.gif