Searches for correlation between UHECR events and high­-energy gamma-­ray Fermi­-LAT data

The sources responsible for ultra high-energy cosmic rays (UHECRs) continue to be one of the most intriguing mysteries in astrophysics.We present a comprehensive search for correlations between high-energy ( $\geq$ 1 GeV) gamma-ray events from the Fermi Large Area Telescope (LAT) and UHECRs ($\geq$ 60 EeV) detected by the Telescope Array and the Pierre Auger Observatory. We perform two separate searches. First, we conduct a standard cross-correlation analysis between the arrival directions of UHECRs and gamma-ray sources in the Second Catalog of Hard Fermi-LAT sources (2FHL). Second,we search for a possible correlation between UHECR directions and unresolved Fermi-LAT gamma-ray emission. We report our findings and their implications in the search for the origin of UHECRs.