TITLE:   GCN CIRCULAR
NUMBER:  29739
SUBJECT: GRB 210401A: Fermi GBM Final Real-time Localization
DATE:    21/04/01 23:27:12 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 LONG GRB

At 23:17:04 UT on 1 Apr 2021, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 210401A (trigger 639011829.029182 / 210401970).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 263.1, Dec = -31.6 (J2000 degrees, equivalent to J2000 17h 32m, -31d 36'), with a statistical uncertainty of 1.8 degrees.

The angle from the Fermi LAT boresight is 98.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210401970/quicklook/glg_skymap_all_bn210401970.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/bn210401970/quicklook/glg_healpix_all_bn210401970.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210401970/quicklook/glg_lc_medres34_bn210401970.gif