Relativistic axion-like particles (ALPs) originating from the stellar
interiors, along with the ones coming from photon-ALP mixing in the galactic
magnetic fields, contribute together to make an energetic component of the ALP
content of the universe. Considering an isotropic distribution of cosmic gamma
rays, it is examined if these high energy axion-like particles could constitute
a measurable isotropic "background" for helioscope-type and existing large
general-purpose particle experiments, taking into account their sensitivity.Comment: To be published in PoS for IDM2010 (Identification of Dark Matter
2010