The recent detection of X-ray flares during the afterglow phase of gamma-ray
bursts (GRBs) suggests an inner-engine origin, at radii inside the forward
shock. There must be inverse Compton (IC) emission arising from such flare
photons scattered by forward shock afterglow electrons when they are passing
through the forward shock. We find that this IC emission produces high energy
gamma-ray flares, which may be detected by AGILE, GLAST and ground-based TeV
telescopes. The anisotropic IC scattering between flare photons and forward
shock electrons does not affect the total IC component intensity, but cause a
time delay of the IC component peak relative to the flare peak. The anisotropic
scattering effect may also weaken, to some extent, the suppression effect of
the afterglow intensity induced by the enhanced electron cooling due to flare
photons. We speculate that this IC component may already have been detected by
EGRET from a very strong burst--GRB940217. Future observations by GLAST may
help to distinguish whether X-ray flares originate from late central engine
activity or from external shocks.Comment: 4 pages, Contributed talk presented at "The First GLAST Symposium",
Feb.5-8 2007, Stanford Universit