TITLE: GCN CIRCULAR NUMBER: 27616 SUBJECT: GRB 200421A: Fermi GBM Final Real-time Localization DATE: 20/04/21 20:56:21 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely LONG GRB At 20:45:59 UT on 21 Apr 2020, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 200421A (trigger 609194764.72639 / 200421865). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 164.0, Dec = 63.8 (J2000 degrees, equivalent to J2000 10h 56m, 63d 47'), with a statistical uncertainty of 2.3 degrees. The angle from the Fermi LAT boresight is 14.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200421865/quicklook/glg_skymap_all_bn200421865.png The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200421865/quicklook/glg_healpix_all_bn200421865.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200421865/quicklook/glg_lc_medres34_bn200421865.gif