TITLE:   GCN CIRCULAR
NUMBER:  39951
SUBJECT: GRB 250330B: Fermi GBM Final Real-time Localization
DATE:    25/03/30 22:03:10 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 SHORT GRB

At 21:52:22 UT on 30 Mar 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250330B (trigger 765064347.102666 / 250330911).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 114.1, Dec = 13.3 (J2000 degrees, equivalent to J2000 07h 36m, 13d 18'), with a statistical uncertainty of 3.1 degrees.

The angle from the Fermi LAT boresight is 81.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250330911/quicklook/glg_skymap_all_bn250330911.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/bn250330911/quicklook/glg_healpix_all_bn250330911.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250330911/quicklook/glg_lc_medres34_bn250330911.gif