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TITLE:   GCN CIRCULAR
NUMBER:  30665
SUBJECT: GRB 210820B: Fermi GBM Final Localization
DATE:    21/08/20 18:26:00 GMT
FROM:    Joshua Wood at MSFC/Fermi-GBM  <joshua.r.wood@nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 00:05:14.01 UT on 20 Aug 2021, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 210820B (trigger 651110719 / 210820004).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 277.0, Dec = +67.0 (J2000 degrees, equivalent to J2000 18h 28m, +67d 00'), with a statistical uncertainty of 5.0 degrees.

The angle from the Fermi LAT boresight is 31.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210820004/quicklook/glg_skymap_all_bn210820004.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210820004/quicklook/glg_healpix_all_bn210820004.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210820004/quicklook/glg_lc_medres34_bn210820004.gif