TITLE:   GCN CIRCULAR
NUMBER:  39629
SUBJECT: GRB 250309B: BALROG localization (Fermi Trigger 763198715 / GRB 250309318)
DATE:    25/03/09 08:04:59 GMT
FROM:    Jochen Greiner at MPE <jcgrog@mpe.mpg.de>

T. Preis (University of Innsbruck) & J. Greiner (MPE Garching) report:

The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
763198715 at 07:38:30 on 09 March 2025 were automatically fitted for spectrum
and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427;
Berlato et al. 2019, ApJ 873, 60).

The best-fit position is:
RA(2000.0) = 210.5 deg
Decl.(2000.0) = -7.6 deg
The 1 sigma statistical error radius is 1.3 deg.
We estimate an additional systematic error of 1 deg.

Further details are available at:
https://grb.mpe.mpg.de/grb/GRB250309318/

The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB250309318/healpix

The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB250309318/json