5 papers
Are topological defects responsible for the 300 EeV cosmic rays?
R. J. Protheroe, P. A. Johnson
We use of a hybrid matrix--Monte Carlo method to simulate the cascade through the cosmic background radiation initiated by UHE particles and radiation emitted by topological defect…
Propagation of Ultra High Energy Protons over Cosmological Distances and Implications for Topological Defect Models
R. J. Protheroe, P. A. Johnson
We describe the results of a hybrid matrix--Monte Carlo calculation of cascading of UHE cosmic rays and -rays through the cosmic background radiation fields over cosmological di…
Rapid Stochastic Acceleration of Protons to Energies Above 100~TeV in the Accretion Column Of Hercules X-1
P. A. Johnson
An investigation into the acceleration of protons by scattering off relativistic Alfvén waves in the accretion column of Hercules X-1 is presented. The mechanism is shown to achiev…
Contribution to the local cosmic-ray flux from the Geminga supernova
P. A. Johnson
The contribution to the local cosmic-ray flux from the Geminga supernova is calculated assuming shock acceleration to 10^14 eV in a remnant which was formed several 10^5 years ago…
"The Contribution of Active Galactic Nuclei to the Diffuse Gamma Ray Background"
P. A. Johnson, A. Mastichiadis, R. J. Protheroe +2
We consider the emission of high energy to very high energy -rays in radio-quiet active galactic nuclei (AGN) or the central regions of radio-loud AGN. We use our results to est…