GCN Circular 40538
Subject
GRB 250523A: Fermi GBM Final Real-time Localization
Date
2025-05-23T14:36:55Z (7 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 14:26:23 UT on 23 May 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250523A (trigger 769703188.305002 / 250523602).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 52.9, Dec = 55.2 (J2000 degrees, equivalent to J2000 03h 31m, 55d 12'), with a statistical uncertainty of 3.0 degrees.
The angle from the Fermi LAT boresight is 38.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250523602/quicklook/glg_skymap_all_bn250523602.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/bn250523602/quicklook/glg_healpix_all_bn250523602.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250523602/quicklook/glg_lc_medres34_bn250523602.gif