Related papers: Extragalactic cosmic rays and their signatures
Neutrinos from far away sources annihilating at the Z resonance on relic neutrinos may give origin to the ultrahigh-energy cosmic rays. Here we present predictions of this mechanism with relic neutrinos lighter than 1 eV, which do not…
The Pierre Auger Collaboration has reported evidence for anisotropy in the distribution of arrival directions of the cosmic rays with energies $E>E_{th}=5.5\times 10^{19}$ eV. These show a correlation with the distribution of nearby…
In this article we examine the hypothesis that the highest energy cosmic rays are complex nuclei from extragalactic sources. Under reasonable physical assumptions, we show that the nearby metally rich starburst galaxies (M82 and NGC 253)…
We study the phenomenology of cosmic-rays (CRs) at the galactic/extragalactic transition, focusing on two opposite models for the composition of the extragalactic (EG) component. Model A assumes a mixed source composition, with nuclear…
We have developed a model that explains cosmic rays with energies E between \~0.3 PeV and the energy of the second knee at E_2 ~ 3*10^{17} eV as originating from a recent Galactic gamma-ray burst (GRB) that occurred ~1 Myr ago within 1 kpc…
The Auger Collaboration reports that the arrival directions of >60 EeV ultra-high energy cosmic rays (UHECRs) cluster along the supergalactic plane and correlate with active galactic nuclei (AGN) within ~100 Mpc. The association of several…
The discoveries of the GZK cutoff with the HiRes and Auger Observatories and the discovery by Auger of clustering of >~60 EeV ultra-high energy cosmic rays (UHECRs) towards nearby <~75 Mpc) AGNs along the supergalactic plane establishes the…
Several kinds of measurements are combined in an attempt to obtain a consistent estimate of the spectrum and composition of the primary cosmic radiation through the knee region. Assuming that the knee is a signal of the high-energy end of a…
We fit the ultrahigh-energy cosmic-ray (UHECR, $E\gtrsim0.1$ EeV) spectrum and composition data from the Pierre Auger Observatory at energies $E\gtrsim5\cdot10^{18}$ eV, i.e., beyond the ankle using two populations of astrophysical sources.…
There are two promising scenarios that explain the ankle, which is a dip in the spectrum of cosmic rays at $\sim 10^{19}$ eV. A scenario interprets the ankle as the transition from Galactic to extragalactic cosmic rays ({\it…
Recent results obtained with the Pierre Auger Observatory are described. These include measurements of the spectrum, anisotropies and composition of ultra-high energy cosmic rays. The ankle of the spectrum is measured at $4\times…
The energy losses and spectra of Ultra High Energy Cosmic Rays (UHECR) are calculated for protons as primary particles. The attention is given to the energy losses due to electron-positron production in collisions with the microwave 2.73 K…
The cosmic ray spectrum has been shown to extend well beyond 10^20 eV. With nearly 20 events observed in the last 40 years, it is now established that particles are accelerated or produced in the universe with energy near 10^21 eV. In all…
A posteriori anisotropy study of ultra-high energy cosmic rays (UHECRs) with the Pierre Auger Observatory (PAO) has shown evidence of excess of cosmic ray particles above 55 EeV within $18^{\circ}$ of the direction of the radio galaxy…
We study the anisotropies on large angular scales which can be present in the flux of cosmic rays reaching the Earth from a population of extragalactic sources, focusing on the energy range between the second knee and the ankle. In this…
A model is introduced, in which the irregularity spectrum of the Galactic magnetic field beyond the dissipation length scale is first a Kolmogorov spectrum $k^{-5/3}$ at small scales $\lambda \, = \, 2 \pi/k$ with $k$ the wave-number, then…
Some general features of cosmic ray acceleration are summarized along with some inferences that can be drawn concerning the origin of the UHE component. The UHE luminosity density is found to be similar to that derived for GeV cosmic rays…
We explore the possibility that the recently detected dipole anisotropy in the arrival directions of~$>8$~EeV ultra-high energy cosmic-rays (UHECRs) arises due to the large-scale structure (LSS). We assume that the cosmic ray sources follow…
We investigate the problem of transition from Galactic cosmic rays to extragalactic ultra high energy cosmic rays. Using the model for extragalactic ultra high energy cosmic rays and observed all-particle cosmic ray spectrum, we calculate…
We review the basic ideas on the origin of cosmic rays with energy in excess of $\sim 10^{19}$ eV, in the light of the most recent observational findings. The limited statistics of events detected by the two largest experiments currently…