TITLE:   GCN CIRCULAR
NUMBER:  33416
SUBJECT: GRB 230307A: BALROG localization (Fermi Trigger  699896651/ GRB 230307656)
DATE:    23/03/08 09:20:58 GMT
FROM:    Jochen Greiner at MPE,Garching  <jcg@mpe.mpg.de>

B. Biltzinger, F. Kunzweiler, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report:

The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
699896651 at 15:44:06 on 07 March 2023 were 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 (1 sigma statistical errors) is:
RA(2000.0) = 41.8+/-0.4 deg
Decl.(2000.0) = -71.5+/-0.1 deg
We estimate an additional systematic error of 2 deg. 

The position is in agreement with the IPN localization (GCN Circ. 33413).

We note that the determined localization is close to the Earth horizon, which could be an additional source of systematic errors. 

Further details are available at:
https://grb.mpe.mpg.de/grb/GRB230307656/?data_version=h01

The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/media/data/GRB230307656/data_files/230308_090913782213_GRB230307656_healpixSysErr_trigdat_h01.fits

The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB230307656/json