TITLE:   GCN CIRCULAR
NUMBER:  40640
SUBJECT: GRB 250606A: Fermi GBM Final Real-time Localization
DATE:    25/06/06 04:39:12 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 04:28:41 UT on 6 Jun 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250606A (trigger 770876926.822872 / 250606187).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 32.3, Dec = -78.2 (J2000 degrees, equivalent to J2000 02h 09m, -78d 12'), with a statistical uncertainty of 2.8 degrees.

The angle from the Fermi LAT boresight is 50.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250606187/quicklook/glg_skymap_all_bn250606187.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250606187/quicklook/glg_healpix_all_bn250606187.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250606187/quicklook/glg_lc_medres34_bn250606187.gif