TITLE:   GCN CIRCULAR
NUMBER:  29871
SUBJECT: GRB 210421C: Fermi GBM Final Real-time Localization
DATE:    21/04/21 20:23:17 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 20:12:53 UT on 21 Apr 2021, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 210421C (trigger 640728778.025922 / 210421842).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 192.2, Dec = -61.9 (J2000 degrees, equivalent to J2000 12h 48m, -61d 53'), with a statistical uncertainty of 14.3 degrees.

The angle from the Fermi LAT boresight is 125.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210421842/quicklook/glg_skymap_all_bn210421842.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/bn210421842/quicklook/glg_healpix_all_bn210421842.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210421842/quicklook/glg_lc_medres34_bn210421842.gif