GCN Circular 33836

The Fermi GBM team reports the detection of a likely LONG GRB At 23:11:39 UT on 20 May 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230520B (trigger 706317104.139708 / 230520966). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 31.7, Dec = -62.1 (J2000 degrees, equivalent to J2000 02h 06m, -62d 06'), with a statistical uncertainty of 1.0 degrees. The angle from the Fermi LAT boresight is 152.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230520966/quicklook/glg_skymap_all_bn230520966.png The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230520966/quicklook/glg_healpix_all_bn230520966.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230520966/quicklook/glg_lc_medres34_bn230520966.gif