TITLE: GCN CIRCULAR NUMBER: 30885 SUBJECT: GRB 210927A: Fermi GBM Final Real-time Localization DATE: 21/09/27 00:54:10 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 SHORT GRB At 00:43:57 UT on 27 Sep 2021, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 210927A (trigger 654396242.858592 / 210927031). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 252.1, Dec = 0.0 (J2000 degrees, equivalent to J2000 16h 48m, 0d 00'), with a statistical uncertainty of 20.8 degrees. The angle from the Fermi LAT boresight is 28.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210927031/q... The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210927031/q... The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210927031/q...