TITLE: GCN CIRCULAR NUMBER: 18714 SUBJECT: Fermi GBM trigger 151221690 is not a GRB DATE: 15/12/21 23:55:57 GMT FROM: Peter Jenke at MSFC P. Jenke (UAH) reports on behalf of the Fermi GBM team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 472408444/151221690 at 16:34:00.82 UT on the 21th of December 2015, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to a local particles."