TITLE:   GCN CIRCULAR
NUMBER:  41565
SUBJECT: GRB 250827A: Fermi GBM Final Real-time Localization
DATE:    25/08/27 15:45:24 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 15:34:53 UT on 27 Aug 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250827A (trigger 778001698.2092 / 250827649).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 346.8, Dec = -43.8 (J2000 degrees, equivalent to J2000 23h 07m, -43d 47'), with a statistical uncertainty of 7.2 degrees.

The angle from the Fermi LAT boresight is 90.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250827649/quicklook/glg_skymap_all_bn250827649.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/bn250827649/quicklook/glg_healpix_all_bn250827649.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250827649/quicklook/glg_lc_medres34_bn250827649.gif