TITLE:   GCN CIRCULAR
NUMBER:  39046
SUBJECT: GRB 250127B: Fermi GBM Final Real-time Localization
DATE:    25/01/27 15:25:16 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 15:14:38 UT on 27 Jan 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250127B (trigger 759683683.583014 / 250127635).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 126.4, Dec = -14.0 (J2000 degrees, equivalent to J2000 08h 25m, -14d 00'), with a statistical uncertainty of 4.8 degrees.

The angle from the Fermi LAT boresight is 96.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250127635/quicklook/glg_skymap_all_bn250127635.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/bn250127635/quicklook/glg_healpix_all_bn250127635.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250127635/quicklook/glg_lc_medres34_bn250127635.gif