TITLE:   GCN CIRCULAR
NUMBER:  39006
SUBJECT: GRB 250121A: Fermi GBM Final Real-time Localization
DATE:    25/01/21 23:46:35 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 23:36:05 UT on 21 Jan 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250121A (trigger 759195370.779232 / 250121983).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 225.1, Dec = -36.9 (J2000 degrees, equivalent to J2000 15h 00m, -36d 53'), with a statistical uncertainty of 1.1 degrees.

The angle from the Fermi LAT boresight is 16.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250121983/quicklook/glg_skymap_all_bn250121983.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/bn250121983/quicklook/glg_healpix_all_bn250121983.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250121983/quicklook/glg_lc_medres34_bn250121983.gif