GRB 210923A
GCN Circular 30873
Subject
Retraction of Fermi GBM GRB 210923A: the trigger is not a GRB
Date
2021-09-23T22:03:59Z (5 years ago)
From
Joe Mangan at UCD <joseph.mangan@ucdconnect.ie>
J.Mangan (UCD), S.Lesage (UAH) report on behalf of the Fermi Gamma-ray
Burst Monitor Team:
The Fermi Gamma-ray Burst Monitor (GBM) trigger 654090581/210923493 at
11:49:36.820 UT
on 23 September 2021, tentatively classified as a GRB (GCN 30865), is in
fact not due
to a GRB. This trigger is likely due to a terrestrial electron beam (TEB).
GCN Circular 30865
Subject
GRB 210923A: Fermi GBM Final Real-time Localization
Date
2021-09-23T11:57:13Z (5 years ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
The Fermi GBM team reports the detection of a likely SHORT GRB
At 11:49:36 UT on 23 Sep 2021, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 210923A (trigger 654090581.820056 / 210923493).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 90.0, Dec = -6.5 (J2000 degrees, equivalent to J2000 06h 00m, -6d 30'), with a statistical uncertainty of 10.9 degrees.
The angle from the Fermi LAT boresight is 47.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210923493/quicklook/glg_skymap_all_bn210923493.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210923493/quicklook/glg_healpix_all_bn210923493.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210923493/quicklook/glg_lc_medres34_bn210923493.gif