TITLE:   GCN CIRCULAR
NUMBER:  36204
SUBJECT: GRB 240421A: Fermi GBM Final Real-time Localization
DATE:    24/04/21 05:32:35 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 05:21:59 UT on 21 Apr 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240421A (trigger 735369724.901026 / 240421224).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 314.2, Dec = -80.2 (J2000 degrees, equivalent to J2000 20h 56m, -80d 12'), with a statistical uncertainty of 7.5 degrees.

The angle from the Fermi LAT boresight is 140.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240421224/quicklook/glg_skymap_all_bn240421224.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240421224/quicklook/glg_healpix_all_bn240421224.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240421224/quicklook/glg_lc_medres34_bn240421224.gif