A correlation between the highest energy cosmic rays and nearby active galactic nuclei detected by Fermi

Abstract

We analyze the correlation of the positions of gamma-ray sources in the Fermi Large Area Telescope First Source Catalog (1FGL) and the First LAT Active Galactic Nuclei (AGN) Catalog (1LAC) with the arrival directions of ultra-high-energy cosmic rays (UHECRs) observed with the Pierre Auger Observatory, in order to investigate the origin of UHECRs. We find that Galactic sources and blazars identified in the 1FGL are not significantly correlated with UHECRs, while the 1LAC sources display a mild correlation (2.6 sigma level) on a ~2.4 degree angular scale. When selecting only the 1LAC AGNs closer than 200 Mpc, we find a strong association (5.4 sigma) between their positions and the directions of UHECRs on a ~17 degree angular scale; the probability of the observed configuration being due to an isotropic flux of cosmic rays is 5x10^{-8}. There is also a 5 sigma correlation with nearby 1LAC sources on a 6.5 degree scale. We identify 7 "gamma-ray loud" AGNs which are associated with UHECRs within ~17 degree and are likely candidates for the production sites of UHECRs: Centaurus A, NGC 4945, ESO 323-G77, 4C+04.77, NGC 1218, RX J0008.0+1450 and NGC 253. We interpret these results as providing additional support to the hypothesis of the origin of UHECRs in nearby extragalactic objects. As the angular scales of the correlations are large, we discuss the possibility that intervening magnetic fields might be considerably deflecting the trajectories of the particles on their way to Earth.

23 pages, 7 figures, accepted for publication in ApJ

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• Comment on "Correlation of the Highest-Energy Cosmic Rays with Nearby Extragalactic Objects"
• Non-thermal transient sources from rotating black holes
• Detection of blueshifted emission and absorption and a relativistic Iron line in the X-ray spectrum of ESO 323-G077

Cited by in corpus (10)

• The Second Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope
• Giant Lobes of Centaurus A Radio Galaxy Observed with the Suzaku X-ray Satellite
• Russian-German Astroparticle Data Life Cycle Initiative
• Statistical Analysis of the Correlation between Active Galactic Nuclei and Ultra-High Energy Cosmic Rays
• A Bayesian analysis of the 27 highest energy cosmic rays detected by the Pierre Auger Observatory
• Constraining Sources of Ultra High Energy Cosmic Rays Using High Energy Observations with the Fermi Satellite
• Chandra observations and classification of AGN-candidates correlated with Auger UHECRs
• Revisit of Correlation Analysis between Active Galactic Nuclei and Ultra-High Energy Cosmic Rays
• Correlation between Ultra-high Energy Cosmic Rays and Active Galactic Nuclei from Fermi Large Area Telescope
• Ultra high-energy cosmic rays from beyond the Greisen-Zatsepin-Kuz'min horizon