相关论文: High-Energy Cosmic Rays from Radio Galaxies
Ultra High Energy Cosmic Rays, UHECR, are charged particles with energies between $\sim10^{18}\,{\rm eV}$ and $\sim3\times10^{20}\,{\rm eV}\sim50\,{\rm J}$. They exhibit fundamental physics at energies inaccessible to terrestrial…
Cosmic-rays with energies exceeding 10^{19} eV are referred to as Ultra High Energy Cosmic Rays (UHECRs). The sources of these particles and their acceleration mechanism are unknown, and for many years have been the issue of much debate.…
From the analysis of the flux of high energy particles, $E>3\cdot 10^{18}eV$, it is shown that the distribution of the power density of extragalactic rays over energy is of the power law, ${\bar q}(E)\propto E^{-2.7}$, with the same index…
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…
The bulk of observed ultrahigh energy cosmic rays could be light or heavier elements, and originate from an either steady or transient population of sources. This leaves us with four general categories of sources. Energetic requirements set…
The quest for the origin(s) of ultra-high-energy cosmic rays (UHECRs) continues to be a far-reaching pillar of high energy astrophysics. The source scrutiny is mostly based on three observables: the energy spectrum, the nuclear composition,…
We present numerical simulations for energy spectra and angular distributions of nucleons above 10^{19} eV injected by the radio-galaxy Centaurus A at a distance 3.4 Mpc and propagating in extra-galactic magnetic fields in the sub-micro…
In this paper we review the main features of the observed Cosmic Rays spectrum in the energy range $10^{17} {\rm eV}~\div~10^{20} {\rm eV}$. We present a theoretical model that explains the main observed features of the spectrum, namely the…
There is mounting evidence from observations of long duration gamma ray bursts (GRBs), supernova remnants (SNR) and the supernova (SN) explosion 1987A, that SN explosions eject highly relativistic bipolar jets of plasmoids (cannonballs) of…
The origin of ultra-high-energy cosmic rays remains one of the central open questions in astroparticle physics. Recent measurements reveal anisotropies in arrival directions, a rigidity-dependent composition dominated by intermediate-mass…
We present spectra and mass composition of cosmic rays incoming to the Earth in the energy range (0.5-2)10^20 eV. As their sources we consider Seyfert galaxies located at distances < 40 Mpc, following an acceleration model for such…
A striking concentration of ultra-high energy cosmic ray (UHECR) events observed by the Pierre Auger Observatory around the direction of the nearby radio galaxy Centaurus A revives the idea that radio galaxies may be dominant sources of…
We consider the phenomenology of cosmic-rays (CRs) and stress the interest of jointly studying their properties over the whole energy spectrum. While UHECRs are known to raise important physical and astrophysical problems, we recall that…
Cosmic ray nuclei, cosmic ray electrons with energy above a few GeV, and the diffuse gamma-ray background radiation (GBR) above a few MeV, presumed to be extragalactic, could all have their origin or residence in our galaxy and its halo.…
We give an outline of possible extragalactic explanations of the highest energy cosmic ray events. We give a classification of the possible particles which could have caused the events and try to find suitable sources for each class. In…
We consider the possibility of explaining the observed spectrum and composition of the cosmic rays with energies above $10^{17}$ eV in terms of two different extragalactic populations of sources in the presence of a turbulent intergalactic…
The greater part of this paper is concerned with a historical discussion of the development of the search for the origins of the highest-energy cosmic-rays together with a few remarks about future prospects. Additionally, in section 6, the…
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…
We study the large-scale distribution of the arrival directions of the highest energy cosmic rays observed by various experiments. Despite clearly insufficient statistics, we find a deficit of cosmic rays at energies higher than 10^{20} eV…
It has recently been shown that the highest energy cosmic rays (CRs) may originate in the same cosmological objects producing $\gamma$-ray bursts. This model requires the presence of intergalactic magnetic fields (IGMF) to delay the arrival…