相关论文: Cosmic Ray Acceleration by E-Parallel Reconnection…
Cosmic ray particles with energies in excess of 10**(20) eV have been detected. The sources as well as the physical mechanism(s) responsible for endowing cosmic ray particles with such enormous energies are unknown. This report gives a…
Nearby radio galaxies (RGs) of Fanaroff-Riley Class I (FR-I) are considered possible sites for the production of observed ultra-high-energy cosmic rays (UHECRs). Among those, some exhibit blazar-like inner jets, while others display…
Galactic cosmic rays are widely believed to be accelerated in expanding shock waves initiated by supernova explosions. The theory of diffusive shock acceleration of cosmic rays is now well established, but two fundamental questions remain…
(abridged) Ultra-high energy cosmic rays (UHECRs) are extremely energetic charged particles with energies surpassing $10^{18}$ eV. Their sources remain elusive, obscured by deflections caused by the Galactic magnetic field (GMF). This…
One prediction of particle acceleration in the supernova remnants in the magnetic wind of exploding Wolf Rayet and Red Super Giant stars is that the final spectrum is a composition of a spectrum $E^{-7/3}$ and a polar cap component of…
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…
In the past year, the HiRes and Auger collaborations have reported the discovery of a high-energy cutoff in the ultra-high energy cosmic-ray (UHECR) spectrum, and an apparent clustering of the highest energy events towards nearby active…
Nearby radio galaxies are among the most promising candidates for the acceleration of ultra-high-energy cosmic rays (UHECRs). In this work, we develop a physically motivated, source-resolved framework to quantify the contribution of the…
Most models of the origin of ultra high energy cosmic rays rely on the existence of luminous extragalactic sources. Cosmic rays escaping the galaxy where the source is located produce a sufficiently large electric current to justify the…
A model for high-energy (>10^14 eV) cosmic rays (HECRs) from galactic and extragalactic gamma-ray bursts (GRBs) is summarized. Relativistic outflows in GRBs are assumed to inject power-law distributions of CR protons and ions to the highest…
The $\gamma$-ray emission observed in several classes of Galactic and extragalactic astrophysical sources appears to be linked to accreting black holes and rotational powered neutron stars. These systems are prodigious cosmic accelerators,…
Recently, the Pierre Auger Observatory has found strong evidence supporting the extragalactic origin of the most energetic cosmic rays. Despite several observed excesses in the distribution of arrival directions for the highest energy…
The composition of Galactic Cosmic Rays (GCR) presents strong similarities to the standard (cosmic) composition, but also noticeable differences, the most important being the high isotopic ratio of Ne22/Ne20 which is about 5 times higher in…
I review the status of ultrahigh-energy cosmic ray (UHECR) physics.After introducing the main experimental results and summarizing possible intepretations, I discuss observational and theoretical constraints on the sources of UHECRs. I…
The energy output (per logarithmic interval of particle energies) of Cosmic Rays (CRs) with energies $10{\rm GeV}\lesssim\varepsilon_p\lesssim100{\rm GeV}$ is $\sim 10^{47}\rm erg$ per solar mass of star$-$formation, based on the CR…
Although cosmic rays were discovered 90 years ago, we do not know how and where they are accelerated. There is compelling evidence that the highest energy cosmic rays are extra-galactic -- they cannot be contained by our galaxy's magnetic…
We present a method to measure cosmic magnetic fields with ultra high energy cosmic rays (UHECRs). We apply an advanced autocorrelation method to simulated UHECRs which includes their directional as well as energy information. Without…
Ultra-high energy cosmic rays interacting with the radiation fields in the universe cause electromagnetic cascades resulting in a flux of extragalactic gamma rays, detectable to some 100 GeV. Recent precise measurements of the extragalactic…
Fanaroff-Riley (FR) 0 radio galaxies compose a new class of radio galaxies, which are usually weaker but much more numerous than the well-established class of FR 1 and FR 2 galaxies. The latter classes have been proposed as sources of the…
Fermi Gamma ray Space Telescope measurements of spectra, variability time scale, and maximum photon energy give lower limits to the apparent jet powers and, through gammagamma opacity arguments, the bulk Lorentz factors of relativistic…