TITLE:   GCN CIRCULAR
NUMBER:  41866
SUBJECT: GRB 250918A: BALROG localization (Fermi Trigger 779891543 / GRB 250918522)
DATE:    25/09/18 13:33:35 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
779891543 at 12:32:18 on 18 Sept. 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) = 225.6 deg
Decl.(2000.0) = -16.2 deg
The 1 sigma statistical error radius is 4.1 deg.
We estimate an additional systematic error of 2 deg.

Further details are available at:
https://grb.mpe.mpg.de/grb/GRB250918522/

The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB250918522/healpix

The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB250918522/json