TITLE: GCN CIRCULAR NUMBER: 40701 SUBJECT: GRB 250612A: BALROG localization (Fermi Trigger 771424081 / GRB 250612519) DATE: 25/06/12 13:17:08 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 771424081 at 12:27:56 on 12 June 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) = 226.1 deg Decl.(2000.0) = -28.9 deg The 1 sigma statistical error radius is 2.4 deg. We estimate an additional systematic error of 1 deg.

This is consistent in time and position with the Einstein Probe detection of the X-ray transient EP 250612a (GCN 40700).

Further details are available at: https://grb.mpe.mpg.de/grb/GRB250612519/

The Healpix map can be downloaded from: https://grb.mpe.mpg.de/grb/GRB250612519/healpix

The location parameters are available as JSON at: https://grb.mpe.mpg.de/grb/GRB250612519/json

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