TITLE: GCN CIRCULAR NUMBER: 39783 SUBJECT: GRB 250319B: Fermi GBM Final Localization DATE: 25/03/19 15:50:43 GMT FROM: Cuán de Barra at UCD cuan.debarra@ucdconnect.ie

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

"At 05:07:28.91 UT on 19 March 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250319B (trigger 764053653/250319214).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 246.18, Dec = -70.90 (J2000 degrees, equivalent to J2000 16h 25m, 70d 54'), with a statistical uncertainty of 3.18 degrees.

The angle from the Fermi LAT boresight is 29 degrees.

The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250319214/q...

The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250319214/q...

The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250319214/q..."

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