TITLE:   GCN CIRCULAR
NUMBER:  30045
SUBJECT: GRB 210518A: Fermi GBM Final Real-time Localization
DATE:    21/05/18 13:15:25 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 13:04:09 UT on 18 May 2021, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 210518A (trigger 643035854.639946 / 210518545).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 270.0, Dec = 49.6 (J2000 degrees, equivalent to J2000 18h 00m, 49d 36'), with a statistical uncertainty of 1.8 degrees.

The angle from the Fermi LAT boresight is 142.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210518545/quicklook/glg_skymap_all_bn210518545.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/bn210518545/quicklook/glg_healpix_all_bn210518545.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210518545/quicklook/glg_lc_medres34_bn210518545.gif