TITLE:   GCN CIRCULAR
NUMBER:  29824
SUBJECT: Fermi Gamma-ray Burst Monitor trigger 640303939/210416925 is not a GRB
DATE:    21/04/17 04:07:35 GMT
FROM:    Oliver J Roberts at USRA/NASA  <oliver.roberts@nasa.gov>

O.J.Roberts (USRA/NASA MSFC) reports on behalf of the Fermi Gamma-ray Burst Monitor Team:

“The Fermi Gamma-ray Burst Monitor (GBM) trigger 640303939/210416925 at 22:12:14.87  UT
on 16 April 2021, tentatively classified as a GRB, is in fact not due to a GRB. 
This trigger is likely due to local particles at SAA entry.