TITLE:   GCN CIRCULAR
NUMBER:  33591
SUBJECT: GRB 230409A: Fermi GBM Final Real-time Localization
DATE:    23/04/09 00:58:47 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 00:48:13 UT on 9 Apr 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230409A (trigger 702694098.828404 / 230409033).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 328.4, Dec = 25.1 (J2000 degrees, equivalent to J2000 21h 53m, 25d 06'), with a statistical uncertainty of 4.0 degrees.

The angle from the Fermi LAT boresight is 77.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230409033/quicklook/glg_skymap_all_bn230409033.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230409033/quicklook/glg_healpix_all_bn230409033.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230409033/quicklook/glg_lc_medres34_bn230409033.gif