GRB 260813A
GCN Circular 45378
Subject
GRB 260813A: BALROG localization (Fermi Trigger 808341387 / GRB 260813803)
Date
2026-08-13T19:45:08Z (17 days ago)
From
Jochen Greiner at MPE <jcgrog@mpe.mpg.de>
Via
email
T. Preis (University of Innsbruck) & J. Greiner (MPE Garching) report:
The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
808341387 at 19:16:22 on 13 Aug. 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) = 240.3 deg
Decl.(2000.0) = -61.7 deg
The 1 sigma statistical error radius is 3.0 deg.
We estimate an additional systematic error of 2 deg.
Further details are available at:
https://grb.mpe.mpg.de/grb/GRB260813803/
The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB260813803/healpix
The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB260813803/json
GCN Circular 45377
Subject
GRB 260813A: Fermi GBM Final Real-time Localization
Date
2026-08-13T19:26:57Z (17 days ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
Via
email
The Fermi GBM team reports the detection of a likely LONG GRB
At 19:16:22 UT on 13 Aug 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260813A (trigger 808341387.08523 / 260813803).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 231.4, Dec = -57.8 (J2000 degrees, equivalent to J2000 15h 25m, -57d 47'), with a statistical uncertainty of 2.5 degrees.
The angle from the Fermi LAT boresight is 46.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260813803/quicklook/glg_skymap_all_bn260813803.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260813803/quicklook/glg_healpix_all_bn260813803.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260813803/quicklook/glg_lc_medres34_bn260813803.gif