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The Pierre Auger Observatory reports that 20 of the 27 highest energy cosmic rays have arrival directions within 3.2 deg of a nearby galaxy in the Veron-Cetty & Veron Catalog of Quasars and Active Galactic Nuclei (12th Ed.), with ~5 of the correlations expected by chance. In this paper we examine the correlated galaxies to gain insight into the possible UHECR sources. We find that 14 of the 21 correlated VCV galaxies are AGNs and we determine their bolometric luminosities. The remaining 7 are primarily star-forming galaxies. The bolometric luminosities of the correlated AGNs are all greater than 5 x 10^{42} erg/s, which may explain the absence of UHECRs from the Virgo region in spite of the large number of VCV galaxies in Virgo, since most of the VCV galaxies in the Virgo region are low luminosity AGNs. Interestingly, the bolometric luminosities of most of the AGNs are significantly lower than required to satisfy the minimum condition for UHECR acceleration in a continuous jet. If a UHECR-AGN correlation is substantiated with further statistics, our results lend support to the recently proposed ``giant AGN flare mechanism for UHECR acceleration.
The origin of the ultra high energy cosmic rays (UHECR) with energies above E > 1017eV, is still unknown. The discovery of their sources will reveal the engines of the most energetic astrophysical accelerators in the universe. This is a written versi
We propose a novel approach for observing cosmic rays at ultra-high energy ($>10^{18}$~eV) by repurposing the existing network of smartphones as a ground detector array. Extensive air showers generated by cosmic rays produce muons and high-energy pho
We present the main results on the energy spectrum and composition of the highest energy cosmic rays of energy exceeding 10$^{18}$ eV obtained by the High Resolution Flys Eye and the Southern Auger Observatory. The current results are somewhat contra
We briefly describe the energy loss processes of ultrahigh energy protons, heavier nuclei and gamma rays in interactions with the universal photon fields of the Universe. We then discuss the modification of the accelerated cosmic ray energy spectrum
(Abridged) Data collected by the Pierre Auger Observatory (Auger) provide evidence for anisotropy in the arrival directions of cosmic rays (CRs) with energies >57 EeV that suggests a correlation with the positions of AGN located within ~75 Mpc. A det