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

TL;DR

This study used the MAGIC telescope to search for very high energy gamma rays from nearby galaxies potentially linked to ultra-high energy cosmic ray sources, setting flux limits and constraining hypothetical source models.

Contribution

First search for VHE gamma rays from specific nearby galaxies associated with UHE cosmic rays using MAGIC, providing flux upper limits and constraining source models.

Findings

No significant VHE gamma ray excess detected from target galaxies.

Upper limits on gamma ray fluxes established in the multi-100 GeV range.

Constraints placed on hypothetical point-like cosmic ray sources.

Abstract

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 the MAGIC telescope for the associated very high energy (VHE) gamma ray emission. Due to constrained propagation distance of such cosmic rays, we selected nearby galaxies in vicinity of the direction of the AGASA triplet and a HiRes UHE cosmic ray event: NGC 3610 and NGC 3613 (quasar remnants); Arp 299 (a system of colliding galaxies). No significant excess in the VHE region was found found from these objects or their surrounding region. At multi-100 GeV regime, the upper limits on fluxes were given against gamma ray sources in surrounding region. The presented limits constrain the flux of a new hypothetical source in the region, provided the cosmic rays are emitted from a single point-like origin.