TITLE: GCN CIRCULAR NUMBER: 40149 SUBJECT: GRB 250416A: Fermi GBM Final Real-time Localization DATE: 25/04/16 14:17:00 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 14:06:21 UT on 16 Apr 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250416A (trigger 766505186.401302 / 250416588).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 323.8, Dec = 70.5 (J2000 degrees, equivalent to J2000 21h 35m, 70d 30'), with a statistical uncertainty of 1.0 degrees.

The angle from the Fermi LAT boresight is 111.0 degrees.

The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250416588/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/bn250416588/q...

The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250416588/q...

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