TITLE: GCN CIRCULAR NUMBER: 41475 SUBJECT: GRB 250821B: BALROG localization (Fermi Trigger / GRB 250821672) DATE: 25/08/21 19:57:25 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 at 16:07:47 on 21 Aug. 2025 were manually 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) = 60.0 deg Decl.(2000.0) = -84.7 deg The 1 sigma statistical error radius is 2.0 deg. We estimate an additional systematic error of 2 deg. Further details are available at: https://grb.mpe.mpg.de/grb/GRB250821672/ The Healpix map can be downloaded from: https://grb.mpe.mpg.de/grb/GRB250821672/healpix The location parameters are available as JSON at: https://grb.mpe.mpg.de/grb/GRB250821672/json View this GCN Circular online at https://gcn.nasa.gov/circulars/41475. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...