Related papers: Superluminal Matter and High-Energy Cosmic Rays
In this chapter I give an overview of shock acceleration, including a discussion of the maximum energies possible and the shape of the spectrum near cut-off, interactions of high energy cosmic rays with, and propagation through, the…
Decaying superheavy particles can be produced by Topological Defects or, in case they are quasi-stable, as relics from the early Universe. The decays of these particles can be the sources of observed Ultra High Energy Cosmic Rays ($E \sim…
Ultra high energy gamma rays produce electron--positron pairs in interactions on the geomagnetic field. The pair electrons suffer magnetic bremsstrahlung and the energy of the primary gamma ray is shared by a bunch of lower energy…
The measurement of ultra-high energy cosmic rays is an unique way to study article interactions at energies which are well above the capability of current accelerators. Significant progress in this field has occurred during last years,…
We present a brief introduction to the physics of Ultra High Energy Cosmic Rays (UHECRs), concentrating on the experimental results obtained so far and on what, from these results, can be inferred about the sources of UHECRs.
The origin of highest energy cosmic rays is yet unknown. An appealing possibility is the so-called Z-burst scenario, in which a large fraction of these cosmic rays are decay products of Z bosons produced in the scattering of ultrahigh…
We explore scenarios where the highest energy cosmic rays are produced by new particle physics near the grand unification scale. Using detailed numerical simulations of extragalactic nucleon, gamma-ray, and neutrino propagation, we show the…
The problem of the origin of Cosmic Rays is now over a century old and while there has been substantial progress, especially in the last decade, there are still open questions. The question of "origin" is open to at least three possible…
We discuss the basic features of the propagation of Ultra High Energy Cosmic Rays in astrophysical backgrounds, comparing two alternative computation schemes to compute the expected fluxes. We also discuss the issue of the transition among…
Compact astrophysical objects produce some of the highest energy light in the universe. The challenge is to determine what mechanism produces these photons.
The search for the origin of cosmic rays is as active as ever, mainly driven by new insights provided by recent pieces of observation. Much effort is being channelled in putting the so called supernova paradigm for the origin of galactic…
The origin and acceleration of high-energy particles in space (cosmic rays), constitute important topics in modern astrophysics. Among the The origin and acceleration of high-energy particles, constituting cosmic rays, is likely to remain…
Ultra high energy cosmic ray events presently show a spectrum, which we interpret here as galactic cosmic rays due to a starburst in the radio galaxy Cen A pushed up in energy by the shock of a relativistic jet. The knee feature and the…
We briefly review sources of cosmic rays, their composition and spectra as well as their propagation in the galactic and extragalactic magnetic fields, both regular and fluctuating. A special attention is paid to the recent results of the…
We briefly review the main channels of gamma ray and neutrino production due to the propagation of ultra high energy cosmic rays. We show how the observations of these secondary radiations are of paramount importance in tagging mass…
Over the last 30 years or so, a handful of events observed in ground-based cosmic ray detectors seem to have opened a new window in the field of high-energy astrophysics. These events have energies exceeding 5x10**19 eV (the region of the…
Astrophysical neutrinos are excellent probes of astroparticle physics and high-energy physics. With energies far beyond solar, supernovae, atmospheric, and accelerator neutrinos, high-energy and ultra-high-energy neutrinos probe fundamental…
Recent measurements of ultra-high energy cosmic rays and neutrinos are briefly reviewed. With several new large scale observatories nearing completion or becoming fully operational only very recently, a large body of high quality and high…
The topological defect scenario of origin of the observed highest energy cosmic rays is reviewed. Under a variety of circumstances, topological defects formed in the early Universe can be sources of very massive particles in the Universe…
The physics results of high energy gamma-ray astronomy are reported, emphasizing recent achievements with ground-based detectors. This includes some of the instrumental developments and latest projects. The fundamental contribution of the…