TITLE: GCN CIRCULAR NUMBER: 32594 SUBJECT: GRB 220927A: Fermi GBM Final Localization DATE: 22/09/27 14:39:49 GMT FROM: Joe Mangan at UCD joseph.mangan@ucdconnect.ie
The Fermi GBM team reports the detection of a likely Long GRB.
"At 05:36:20.95 UT on 27 September 2022, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB220927A (trigger 685949785 / 220927234).
The on-ground calculated location, using the GBM trigger data, is RA = 96.2, DEC = -22.5 (J2000 degrees, equivalent to 6h 24m, -22d 30'), with a statistical uncertainty of 1 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which we have characterized as a core-plus-tail model, with 90% of GRBs having a 3.7 deg error and a small tail suffering a larger than 10 deg systematic error. [Connaughton et al. 2015, ApJS, 216, 32] ).
The angle from the Fermi LAT boresight at the GBM trigger time is 57 degrees.
The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220927234/q...
The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220927234/q...
The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220927234/q...