GCN Circular 39792
Subject
GRB 250320B: Fermi GBM Final Real-time Localization
Date
2025-03-20T23:25:50Z (6 days ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
Via
email
The Fermi GBM team reports the detection of a likely LONG GRB
At 23:15:22 UT on 20 Mar 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250320B (trigger 764205327.02257 / 250320969).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 249.2, Dec = -21.8 (J2000 degrees, equivalent to J2000 16h 36m, -21d 48'), with a statistical uncertainty of 1.0 degrees.
The angle from the Fermi LAT boresight is 31.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250320969/quicklook/glg_skymap_all_bn250320969.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/bn250320969/quicklook/glg_healpix_all_bn250320969.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250320969/quicklook/glg_lc_medres34_bn250320969.gif