EGRET observations of extended high‐energy emissions from the nuclear line flares of June 1991

EGRET onboard the Compton Gamma Ray Observatory observed four energetic X‐type solar flares during June 1991. Two of these flares were in the EGRET spark chamber field of view and were observed to have high energy gamma ray emission lasting hours after the impulsive phase of the flare. Measurements of all four flares were obtained by the EGRET large NaI spectrometer.