We describe a method to analyse inclined air showers produced by ultra high energy cosmic rays using an analytical description of the muon densities. We report the results obtained using data from inclined events (60 • < θ < 80 •) recorded by the Haverah Park shower detector for energies above 10 19 eV. Using mass independent knowledge of the UHECR spectrum obtained from vertical air shower mea...

EGRET data on the Gamma ray emission from the inner Galaxy have shown a rather flat spectrum. This spectrum extends to about 50 GeV in photon energy. It is usually assumed that these gamma-rays arise from the interactions of cosmic ray nuclei with ambient matter. Cosmic Ray particles have been observed up to 3 10 20 eV, with many arguments suggesting, that up to about 3 10 18 eV they are of Gal...

A spectrometer on the International Space Station has measured energy spectrum of iron—the heaviest cosmic-ray element characterized to date.

Identifying the sources of ultrahigh energy cosmic rays remains one of the major challenges in astrophysics. If these cosmic rays are not too severely deflected by magnetic fields while in transit, then their arrival directions will provide crucial information about their origins. The High Resolution Fly’s Eye (HiRes) experiment, consisting of two air fluorescence detector sites, has been makin...

Motivated by recent experimental proposals to search for extragalactic cosmic rays (including anti-matter from distant galaxies), we study particle propagation through the intergalactic medium (IGM). We first use estimates of the magnetic field strength between galaxies to constrain the mean free path for diffusion of particles through the IGM. We then develop a simple analytic model to describ...