TITLE:   GCN CIRCULAR
NUMBER:  44361
SUBJECT: GRB 260421B: BALROG localization (Fermi Trigger 798437606 / GRB 260421176)
DATE:    26/04/21 04:54:24 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
798437606 at 04:13:21 on 21 April 2026 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) = 190.5 deg
Decl.(2000.0) = -16.5 deg
The 1 sigma statistical error radius is 2.2 deg.
We estimate an additional systematic error of 1 deg.

Further details are available at:
https://grb.mpe.mpg.de/grb/GRB260421176/

The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB260421176/healpix

The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB260421176/json