GCN Circular 38873
Subject
GRB 250109A /EP250109a: Fermi GBM Final Localization
Date
2025-01-09T16:02:55Z (a month ago)
From
Utkarsh Pathak at IIT Bombay <utkarshpathak.07@gmail.com>
Via
Web form
The Fermi GBM team reports the detection of a likely LONG GRB
At 06:17:08.60 UT on 9 January 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250109A (trigger 758096233/250109262).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 84.43, Dec = 2.26 (J2000 degrees, equivalent to J2000 05h 37m, 02d 15'), with a statistical uncertainty of 13.52 degrees. This event is associated with EP250109a (Li et al. 2025, GCN 38864).
The angle from the Fermi LAT boresight is 69.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250109262/quicklook/glg_skymap_all_bn250109262.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250109262/quicklook/glg_healpix_all_bn250109262.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250109262/quicklook/glg_lc_medres34_bn250109262.gif