Search for very high energy gamma rays from possible ultra-high energy cosmic ray sources by the MAGIC Telescope

摘要

The origin of ultra-high energy (UHE) cosmic rays is still an open question.In the present work, we searched the possible UHE cosmic ray sources using theMAGIC telescope for the associated very high energy (VHE) gamma ray emission.Due to constrained propagation distance of such cosmic rays, we selected nearbygalaxies in vicinity of the direction of the AGASA triplet and a HiRes UHEcosmic ray event: NGC 3610 and NGC 3613 (quasar remnants); Arp 299 (a system ofcolliding galaxies). No significant excess in the VHE region was found foundfrom these objects or their surrounding region. At multi-100 GeV regime, theupper limits on fluxes were given against gamma ray sources in surroundingregion. The presented limits constrain the flux of a new hypothetical source inthe region, provided the cosmic rays are emitted from a single point-likeorigin.